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Software Development Blogs: Programming, Software Testing, Agile, Project Management
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Android changes for NDK developers

Android Developers Blog - Mon, 06/27/2016 - 23:53

Posted by Dmitry Malykhanov, Developer Advocate

Related to other improvements to the Android platform, the dynamic linker in Android M and N has stricter requirements for writing clean, cross-platform compatible native code in order to load. It is necessary that an application’s native code follows the rules and recommendations in order to ensure a smooth transition to recent Android releases.

Below we outline in detail each individual change related to native code loading, the consequences and steps you can take to avoid issues.

Required tools: there is an <arch>-linux-android-readelf binary (e.g. arm-linux-androideabi-readelf or i686-linux-android-readelf) for each architecture in the NDK (under toolchains/), but you can use readelf for any architecture, as we will be doing basic inspection only. On Linux you need to have the “binutils” package installed for readelf, and “pax-utils” for scanelf.

Private API (Enforced since API 24)

Native libraries must use only public API, and must not link against non-NDK platform libraries. Starting with API 24 this rule is enforced and applications are no longer able to load non-NDK platform libraries. The rule is enforced by the dynamic linker, so non-public libraries are not accessible regardless of the way code tries to load them: System.loadLibrary(...), DT_NEEDED entries, and direct calls to dlopen(...) will fail in exactly the same way.

Users should have a consistent app experience across updates, and developers shouldn’t have to make emergency app updates to handle platform changes. For that reason, we recommend against using private C/C++ symbols. Private symbols aren’t tested as part of the Compatibility Test Suite (CTS) that all Android devices must pass. They may not exist, or they may behave differently. This makes apps that use them more likely to fail on specific devices, or on future releases --- as many developers found when Android 6.0 Marshmallow switched from OpenSSL to BoringSSL.

In order to reduce the user impact of this transition, we’ve identified a set of libraries that see significant use from Google Play’s most-installed apps, and that are feasible for us to support in the short term (including libandroid_runtime.so, libcutils.so, libcrypto.so, and libssl.so). In order to give you more time to transition, we will temporarily support these libraries; so if you see a warning that means your code will not work in a future release -- please fix it now!

$ readelf --dynamic libBroken.so | grep NEEDED
 0x00000001 (NEEDED)                     Shared library: [libnativehelper.so]
 0x00000001 (NEEDED)                     Shared library: [libutils.so]
 0x00000001 (NEEDED)                     Shared library: [libstagefright_foundation.so]
 0x00000001 (NEEDED)                     Shared library: [libmedia_jni.so]
 0x00000001 (NEEDED)                     Shared library: [liblog.so]
 0x00000001 (NEEDED)                     Shared library: [libdl.so]
 0x00000001 (NEEDED)                     Shared library: [libz.so]
 0x00000001 (NEEDED)                     Shared library: [libstdc++.so]
 0x00000001 (NEEDED)                     Shared library: [libm.so]
 0x00000001 (NEEDED)                     Shared library: [libc.so]

Potential problems: starting from API 24 the dynamic linker will not load private libraries, preventing the application from loading.

Resolution: rewrite your native code to rely only on public API. As a short term workaround, platform libraries without complex dependencies (libcutils.so) can be copied to the project. As a long term solution the relevant code must be copied to the project tree. SSL/Media/JNI internal/binder APIs should not be accessed from the native code. When necessary, native code should call appropriate public Java API methods.

A complete list of public libraries is available within the NDK, under platforms/android-API/usr/lib.

Note: SSL/crypto is a special case, applications must NOT use platform libcrypto and libssl libraries directly, even on older platforms. All applications should use GMS Security Provider to ensure they are protected from known vulnerabilities.

Missing Section Headers (Enforced since API 24)

Each ELF file has additional information contained in the section headers. These headers must be present now, because the dynamic linker uses them for sanity checking. Some developers try to strip them in an attempt to obfuscate the binary and prevent reverse engineering. (This doesn’t really help because it is possible to reconstruct the stripped information using widely-available tools.)

$ readelf --header libBroken.so | grep 'section headers'
  Start of section headers:          0 (bytes into file)
  Size of section headers:           0 (bytes)
  Number of section headers:         0
$

Resolution: remove the extra steps from your build that strip section headers.

Text Relocations (Enforced since API 23)

Starting with API 23, shared objects must not contain text relocations. That is, the code must be loaded as is and must not be modified. Such an approach reduces load time and improves security.

The usual reason for text relocations is non-position independent hand-written assembler. This is not common. Use the scanelf tool as described in our documentation for further diagnostics:

$ scanelf -qT libTextRel.so
  libTextRel.so: (memory/data?) [0x15E0E2] in (optimized out: previous simd_broken_op1) [0x15E0E0]
  libTextRel.so: (memory/data?) [0x15E3B2] in (optimized out: previous simd_broken_op2) [0x15E3B0]
[skipped the rest]

If you have no scanelf tool available, it is possible to do a basic check with readelf instead, look for either a TEXTREL entry or the TEXTREL flag. Either alone is sufficient. (The value corresponding to the TEXTREL entry is irrelevant and typically 0 --- simply the presence of the TEXTREL entry declares that the .so contains text relocations). This example has both indicators present:

$ readelf --dynamic libTextRel.so | grep TEXTREL
 0x00000016 (TEXTREL)                    0x0
 0x0000001e (FLAGS)                      SYMBOLIC TEXTREL BIND_NOW
$

Note: it is technically possible to have a shared object with the TEXTREL entry/flag but without any actual text relocations. This doesn’t happen with the NDK, but if you’re generating ELF files yourself make sure you’re not generating ELF files that claim to have text relocations, because the Android dynamic linker trusts the entry/flag.

Potential problems: Relocations enforce code pages being writable, and wastefully increase the number of dirty pages in memory. The dynamic linker has issued warnings about text relocations since Android K (API 19), but on API 23 and above it refuses to load code with text relocations.

Resolution: rewrite assembler to be position independent to ensure no text relocations are necessary. Check the Gentoo documentation for cookbook recipes.

Invalid DT_NEEDED Entries (Enforced since API 23)

While library dependencies (DT_NEEDED entries in the ELF headers) can be absolute paths, that doesn’t make sense on Android because you have no control over where your library will be installed by the system. A DT_NEEDED entry should be the same as the needed library’s SONAME, leaving the business of finding the library at runtime to the dynamic linker.

Before API 23, Android’s dynamic linker ignored the full path, and used only the basename (the part after the last ‘/’) when looking up the required libraries. Since API 23 the runtime linker will honor the DT_NEEDED exactly and so it won’t be able to load the library if it is not present in that exact location on the device.

Even worse, some build systems have bugs that cause them to insert DT_NEEDED entries that point to a file on the build host, something that cannot be found on the device.

$ readelf --dynamic libSample.so | grep NEEDED
 0x00000001 (NEEDED)                     Shared library: [libm.so]
 0x00000001 (NEEDED)                     Shared library: [libc.so]
 0x00000001 (NEEDED)                     Shared library: [libdl.so]
 0x00000001 (NEEDED)                     Shared library:
[C:\Users\build\Android\ci\jni\libBroken.so]
$

Potential problems: before API 23 the DT_NEEDED entry’s basename was used, but starting from API 23 the Android runtime will try to load the library using the path specified, and that path won’t exist on the device. There are broken third-party toolchains/build systems that use a path on a build host instead of the SONAME.

Resolution: make sure all required libraries are referenced by SONAME only. It is better to let the runtime linker to find and load those libraries as the location may change from device to device.

Missing SONAME (Used since API 23)

Each ELF shared object (“native library”) must have a SONAME (Shared Object Name) attribute. The NDK toolchain adds this attribute by default, so its absence indicates either a misconfigured alternative toolchain or a misconfiguration in your build system. A missing SONAME may lead to runtime issues such as the wrong library being loaded: the filename is used instead when this attribute is missing.

$ readelf --dynamic libWithSoName.so | grep SONAME
 0x0000000e (SONAME)                     Library soname: [libWithSoName.so]
$

Potential problems: namespace conflicts may lead to the wrong library being loaded at runtime, which leads to crashes when required symbols are not found, or you try to use an ABI-incompatible library that isn’t the library you were expecting.

Resolution: the current NDK generates the correct SONAME by default. Ensure you’re using the current NDK and that you haven’t configured your build system to generate incorrect SONAME entries (using the -soname linker option).

Please remember, clean, cross-platform code built with a current NDK should have no issues on Android N. We encourage you to revise your native code build so that it produces correct binaries.

Categories: Programming

Android Mobile Vision restores operation and adds Text API

Android Developers Blog - Mon, 06/27/2016 - 21:07

Posted by Michael Sipe, Product Manager

As an important framework for finding objects in photos and video, Mobile Vision operation for Android devices is restored in Google Play Services v9.2.

This new version of Google Play Services fixes a download issue in Google Play Services v.9.0 that caused a service outage. See release notes for details.

We’re also pleased to announce the Text API, a new component for Android Mobile Vision.

The Text API’s optical character recognition technology reads Latin character text (e.g. English, Spanish, German, French, etc.) in photos and returns the text as well as the organizational structure (paragraphs, lines, words). Mobile apps can now:

  • Organize photos that contain text
  • Automate tedious data entry for credit cards, receipts, and business cards
  • Translate documents (along with the Cloud Translate API)
  • Keep track of real objects, such as reading the numbers on subway trains
  • Provide accessibility features

If you want to get started quickly, you can try our codelab which will get Android developers reading text with their apps in under an hour.

Like the Mobile Vision Face and Barcode components, the Text API runs on-device and is suitable for real-time applications. For more information, check out the Mobile Vision Developer site.

Categories: Programming

TensorFlow v0.9 now available with improved mobile support

Google Code Blog - Mon, 06/27/2016 - 19:56

Posted by Pete Warden, Software Engineer

When we started building TensorFlow, supporting mobile devices was a top priority. We were already supporting many of Google’s mobile apps like Translate, Maps, and the Google app, which use neural networks running on devices. We knew that we had to make mobile a first-class part of open source TensorFlow.

TensorFlow has been available to developers on Android since launch, and today we're happy to add iOS in v0.9 of TensorFlow, along with Raspberry Pi support and new compilation options.

To build TensorFlow on iOS we’ve created a set of scripts, including a makefile, to drive the cross-compilation process. The makefile can also help you build TensorFlow without using Bazel, which is not always available.

All this is in the latest TensorFlowdistribution. You can read more by visiting our Mobile TensorFlow guide and the documentation in our iOS samples and Android sample. The mobile samples allow you to classify images using the ImageNet Inception v1 classifier.

These mobile samples are just the beginning---we'd love your help and your contributions. Tag social media posts with #tensorflow so we can hear about your projects!

See the full TensorFlow 0.9.0 release notes here.

Categories: Programming

New Google Cast SDK released for Android and iOS

Google Code Blog - Mon, 06/27/2016 - 19:28

Posted by Adam Champy, Product Manager for Google Cast SDK

Google Cast makes it easy for developers to extend their mobile experience to the most beautiful screens and speakers in the home.

At Google I/O, we announced our new Google Cast SDK. This new SDK focuses on making development for Cast quicker, more reliable, and easier to maintain. We’ve introduced full state management that helps you implement the right abstraction between your app and Google Cast. We’ve also delivered a full Cast user experience, matching the Google Cast design checklist.

Today we are releasing this SDK for Android and iOS Senders, including an introductory video, full documentation, and reference sample apps and codelab tutorials for both platforms. Initial developer feedback is that first-time implementations can save significant development time compared with our previous SDKs.


A few things we’ve announced will be coming in the next few months, including a customizable Expanded Controller and adding customization to the Mini Controller, to help accelerate development even further.

Drop by our Cast developer site to learn about the new SDK and APIs, and join our developer community on Google+ at g.co/googlecastdev to discuss this with other developers.

Categories: Programming

Create Intelligent, Context-Aware Apps with the Google Awareness APIs

Android Developers Blog - Mon, 06/27/2016 - 18:29

Posted by Bhavik Singh, Product Manager

Last month at Google I/O 2016 we announced the new Google Awareness APIs, enabling your apps to intelligently react to user context using snapshots and fences with minimal impact on system resources.

Today we’re proud to announce that the Google Awareness API is available to all developers through Google Play services.

Using 7 different types of context—including location, weather, user activity, and nearby beacons—your app can better understand your users’ current situations, and use this information to provide optimized and customized experiences.

The Awareness API offers two ways to take advantage of context signals within your app:

  • The Snapshot API lets your app easily request information about the user's current context. For example, "give me the user's current location and the current weather conditions".
  • The Fence API lets your app react to changes in user’s context - and when it matches a certain set of conditions. For example, "tell me whenever the user is walking and their headphones are plugged in". Similar to the Geofencing API, once an awareness fence is registered, it can send callbacks to your app even when it's not running.

As a single, simplified surface, the Awareness APIs combine optimally processed context signals in new ways that were not previously possible, providing more accurate and insightful context cues, while also managing system resources to save battery and minimize bandwidth.

We’ve worked closely with some of our partners, who have already found amazing ways to integrate context awareness into their apps:

Trulia, an online residential real estate site, uses our Fence API to suggest open houses. When the weather is perfect and the user is walking around near a house they are interested in, Trulia sends a notification reminding them to stop by. This sort of tailored notification can help users engage with open houses at the perfect time for them.

SuperPlayer Music, on the other hand, uses our Snapshot API and Fence API to suggest the perfect music to match your mood. Whether you’re just finishing up a run and beginning to stretch, setting off on a long car ride, or just getting to the gym, their assistant can understand your context and suggest the right playlist for you.

With our initial set of signals and our awesome partners, we’re just getting started with the Awareness APIs. Join us on a journey to build tailored experiences within your apps, by getting started with the Google Awareness API developer documentation, and learn more by watching our Google I/O session


Categories: Programming

Reimagine Your Productivity at Getting Results.com

image

Imagine if you could master your motivation, your productivity, and your time management?

It’s time to get your game on.

I’ve completely revamped Getting Results.com (http://GettingResults.com) to help you think, feel, and do your best in any situation.

At Getting Results.com you can learn all about Agile Results.  It’s more than just a time management system or a productivity system.

It’s a personal results system for work and life.

Agile Results is a simple system for meaningful results.

It helps you respond to change while making things happen.  It helps you use your best energy for your best results, while you keep learning and improving.

What Will You Find at Getting Results.com?

Getting Results.com is a source of insight, inspiration, and action for mastering productivity, motivation, time management and more.

Here are some of the key things you’ll have access to:

  1. Get Started with Agile Results.
  2. Articles on Agile Results, Goals, Motivation, and More.
  3. 7 Day Agile Results Jumpstart, helps you take Agile Results for a test-drive and potentially have one of your best weeks.  Ever.
  4. 30 Days of Getting Results, this is advanced training that will help you get better results for work and life.
  5. Resources that include Cheat Sheets, Checklists, How Tos, Visuals, and more.

You can also read Success Stories to hear about how others have implemented and are using Agile Results.

Getting Started with Agile Results

While there are a lot of resources at Getting Results.com, the most important thing you can actually do is just get started with Agile Results:

Get Started with Agile Results

Take it for a test drive and see if you can create better results at work and in your life, the Agile Way.

Categories: Architecture, Programming

Project Bloks: Making code physical for kids

Google Code Blog - Mon, 06/27/2016 - 16:46

Originally posted on Google Research Blog


Posted by Steve Vranakis and Jayme Goldstein, Executive Creative Director and Project Lead, Google Creative Lab
At Google, we’re passionate about empowering children to create and explore with technology. We believe that when children learn to code, they’re not just learning how to program a computer—they’re learning a new language for creative expression and are developing computational thinking: a skillset for solving problems of all kinds.
In fact, it’s a skillset whose importance is being recognised around the world—from President Obama’s CS4All program to the inclusion of Computer Science in the UK National Curriculum. We’ve long supported and advocated the furthering of CS education through programs and platforms such as Blockly, Scratch Blocks, CS First and Made w/ Code.
Today, we’re happy to announce Project Bloks, a research collaboration between Google, Paulo Blikstein (Stanford University) and IDEO with the goal of creating an open hardware platform that researchers, developers and designers can use to build physical coding experiences. As a first step, we’ve created a system for tangible programming and built a working prototype with it. We’re sharing our progress before conducting more research over the summer to inform what comes next.
Physical codingKids are inherently playful and social. They naturally play and learn by using their hands, building stuff and doing things together. Making code physical - known as tangible programming - offers a unique way to combine the way children innately play and learn with computational thinking.
Project Bloks is preceded and shaped by a long history of educational theory and research in the area of hands-on learning. From Friedrich Froebel, Maria Montessori and Jean Piaget’s pioneering work in the area of learning by experience, exploration and manipulation, to the research started in the 1970s by Seymour Papert and Radia Perlman with LOGO and TORTIS. This exploration has continued to grow and includes a wide range of research and platforms.
However, designing kits for tangible programming is challenging—requiring the resources and time to develop both the software and the hardware. Our goal is to remove those barriers. By creating an open platform, Project Bloks will allow designers, developers and researchers to focus on innovating, experimenting and creating new ways to help kids develop computational thinking. Our vision is that, one day, the Project Bloks platform becomes for tangible programming what Blockly is for on-screen programming. The Project Bloks systemWe’ve designed a system that developers can customise, reconfigure and rearrange to create all kinds of different tangible programming experiences. A birdseye view of the customisable and reconfigurable Project Bloks systemThe Project Bloks system is made up of three core components the “Brain Board”, “Base Boards” and “Pucks”. When connected together they create a set of instructions which can be sent to connected devices, things like toys or tablets, over wifi or Bluetooth. The three core components of the Project Bloks systemPucks: abundant, inexpensive, customisable physical instructionsPucks are what make the Project Bloks system so versatile. They help bring the infinite flexibility of software programming commands to tangible programming experiences. Pucks can be programmed with different instructions, such as ‘turn on or off’, ‘move left’ or ‘jump’. They can also take the shape of many different interactive forms—like switches, dials or buttons. With no active electronic components, they’re also incredibly cheap and easy to make. At a minimum, all you'd need to make a puck is a piece of paper and some conductive ink. Pucks allow for the creation and customisation of endless amount of different domain-specific physical instructions cheaply and easily.Base Boards: a modular design for diverse tangible programming experiencesBase Boards read a Puck’s instruction through a capacitive sensor. They act as a conduit for a Puck’s command to the Brain Board. Base Boards are modular and can be connected in sequence and in different orientations to create different programming flows and experiences. The modularity of the Base Boards means they can be arranged in different configurations and flowsEach Base Board is fitted with a haptic motor and LEDs that can be used to give end-users real time feedback on their programming experience. The Base Boards can also trigger audio feedback from the Brain Board’s built-in speaker. Brain Board: control any device that has an API over WiFi or BluetoothThe Brain Board is the processing unit of the system, built on a Raspberry Pi Zero. It also provides the other boards with power, and contains an API to receive and send data to the Base Boards. It sends the Base Boards’ instructions to any device with WiFi or Bluetooth connectivity and an API. As a whole, the Project Bloks system can take on different form factors and be made out of different materials. This means developers have the flexibility to create diverse experiences that can help kids develop computational thinking: from composing music using functions to playing around with sensors or anything else they care to invent. The Project Bloks system can be used to create all sorts of different physical programming experiences for kidsThe Coding KitTo show how designers, developers, and researchers might make use of system, the Project Bloks team worked with IDEO to create a reference device, called the Coding Kit. It lets kids learn basic concepts of programming by allowing them to put code bricks together to create a set of instructions that can be sent to control connected toys and devices—anything from a tablet, to a drawing robot or educational tools for exploring science like LEGO® Education WeDo 2.0. What’s next?We are looking for participants (educators, developers, parents and researchers) from around the world who would like to help shape the future of Computer Science education by remotely taking part in our research studies later in the year. If you would like to be part of our research study or simply receive updates on the project, please sign up. If you want more context and detail on Project Bloks, you can read our position paper. Finally, a big thank you to the team beyond Google who’ve helped us get this far—including the pioneers of tangible learning and programming who’ve inspired us and informed so much of our thinking.
Categories: Programming

Improving Stability with Private C/C++ Symbol Restrictions in Android N

Android Developers Blog - Sat, 06/25/2016 - 02:04

Posted by Dimitry Ivanov & Elliott Hughes, Software Engineers

As documented in the Android N behavioral changes, to protect Android users and apps from unforeseen crashes, Android N will restrict which libraries your C/C++ code can link against at runtime. As a result, if your app uses any private symbols from platform libraries, you will need to update it to either use the public NDK APIs or to include its own copy of those libraries. Some libraries are public: the NDK exposes libandroid, libc, libcamera2ndk, libdl, libGLES, libjnigraphics, liblog, libm, libmediandk, libOpenMAXAL, libOpenSLES, libstdc++, libvulkan, and libz as part of the NDK API. Other libraries are private, and Android N only allows access to them for platform HALs, system daemons, and the like. If you aren’t sure whether your app uses private libraries, you can immediately check it for warnings on the N Developer Preview.

We’re making this change because it’s painful for users when their apps stop working after a platform update. Whether they blame the app developer or the platform, everybody loses. Users should have a consistent app experience across updates, and developers shouldn’t have to make emergency app updates to handle platform changes. For that reason, we recommend against using private C/C++ symbols. Private symbols aren’t tested as part of the Compatibility Test Suite (CTS) that all Android devices must pass. They may not exist, or they may behave differently. This makes apps that use them more likely to fail on specific devices, or on future releases — as many developers found when Android 6.0 Marshmallow switched from OpenSSL to BoringSSL.

You may be surprised that there’s no STL in the list of NDK libraries. The three STL implementations included in the NDK — the LLVM libc++, the GNU STL, and libstlport — are intended to be bundled with your app, either by statically linking into your library, or by inclusion as a separate shared library. In the past, some developers have assumed that they didn’t need to package the library because the OS itself had a copy. This assumption is incorrect: a particular STL implementation may disappear (as was the case with stlport, which was removed in Marshmallow), may never have been available (as is the case with the GNU STL), or it may change in ABI incompatible ways (as is the case with the LLVM libc++).

In order to reduce the user impact of this transition, we’ve identified a set of libraries that see significant use from Google Play’s most-installed apps, and that are feasible for us to support in the short term (including libandroid_runtime.so, libcutils.so, libcrypto.so, and libssl.so). For legacy code in N, we will temporarily support these libraries in order to give you more time to transition. Note that we don't intend to continue this support in any future Android platform release, so if you see a warning that means your code will not work in a future release — please fix it now!

Table 1. What to expect if your app is linking against private native libraries.

Libraries App's targetSdkVersion Runtime access via dynamic linker Impact, N Developer Preview Impact, Final N Release Impact, future platform version NDK Public Any Accessible Private (graylist) <=23 Temporarily accessible Warning / Toast Warning Error >=24 Restricted Error Error Error Private (all other)> Any Restricted Error Error Error What behavior will I see?

Please test your app during the N Previews.

N Preview behavior
  • All public NDK libraries (libandroid, libc, libcamera2ndk, libdl, libGLES, libjnigraphics, liblog, libm, libmediandk, libOpenMAXAL, libOpenSLES, libstdc++, libvulkan, and libz), plus libraries that are part of your app are accessible.
  • For all other libraries you’ll see a warning in logcat and a toast on the display. This will happen only if your app’s targetSdkVersion is less than N. If you change your manifest to target N, loading will fail: Java’s System.loadLibrary will throw, and C/C++’s dlopen(3) will return NULL.

Test your apps on the Developer Preview — if you see a toast like this one, your app is accessing private native APIs. Please fix your code soon!

N Final Release behavior
  • All NDK libraries (libandroid, libc, libcamera2ndk, libdl, libGLES, libjnigraphics, liblog, libm, libmediandk, libOpenMAXAL, libOpenSLES, libstdc++, libvulkan, and libz), plus libraries that are part of your app are accessible.
  • For the temporarily accessible libraries (such as libandroid_runtime.so, libcutils.so, libcrypto.so, and libssl.so), you’ll see a warning in logcat for all API levels before N, but loading will fail if you update your app so that its targetSdkVersion is N or later.
  • Attempts to load any other libraries will fail in the final release of Android N, even if your app is targeting a pre-N platform version.
Future platform behavior
  • In O, all access to the temporarily accessible libraries will be removed. As a result, you should plan to update your app regardless of your targetSdkVersion prior to O. If you believe there is missing functionality from the NDK API that will make it impossible for you to transition off a temporarily accessible library, please file a bug here.
What do the errors look like?

Here’s some example logcat output from an app that hasn’t bumped its target SDK version (and so the restriction isn’t fully enforced because this is only the developer preview):

03-21 17:07:51.502 31234 31234 W linker  : library "libandroid_runtime.so"
("/system/lib/libandroid_runtime.so") needed or dlopened by
"/data/app/com.popular-app.android-2/lib/arm/libapplib.so" is not accessible
for the namespace "classloader-namespace" - the access is temporarily granted
as a workaround for http://b/26394120

This is telling you that your library “libapplib.so” refers to the library “libandroid_runtime.so”, which is a private library.

When Android N ships, or if you set your target SDK version to N now, you’ll see something like this if you try to use System.loadLibrary from Java:

java.lang.UnsatisfiedLinkError: dlopen failed: library "libcutils.so"
("/system/lib/libcutils.so") needed or dlopened by "/system/lib/libnativeloader.so"
is not accessible for the namespace "classloader-namespace"
  at java.lang.Runtime.loadLibrary0(Runtime.java:977)
  at java.lang.System.loadLibrary(System.java:1602)

If you’re using dlopen(3) from C/C++ you’ll get a NULL return and dlerror(3) will return the same “dlopen failed...” string as shown above.

For more information about how to check if your app is using private symbols, see the FAQ on developer.android.com.

Categories: Programming

Grow your business on Google Play with help from the new Playbook for Developers app

Android Developers Blog - Fri, 06/24/2016 - 18:08

Posted by Dom Elliott, the Google Play team

Today, the Playbook for Developers mobile app is now generally available for Android devices. The app helps you stay up-to-date with the features and best practices to grow your business on Google Play. Thanks to all our beta testers over the last six weeks whose feedback helped us tweak and refine the app in preparation for launch.

Here’s how you read and watch content in the Playbook for Developers app:

  • Choose topics relating to your business interests to personalize My Playbook with curated articles and videos from Google and experts across the web.
  • Explore the in-depth guide to Google’s developer products, with articles grouped by what you’re trying to do: develop, launch, engage, grow, and earn.
  • Take actions on items – complete, share, save, or dismiss them – and read your Saved articles later, including offline if they’re written in the app. A data connection will be needed to read articles and videos from across the web.

The app supports Android 5.0 and above. If you're on an older device, check out our ebook, The Secrets to App Success on Google Play. We will be adding and updating content in the app to help you stay up-to-date and grow your business. Get the Playbook for Developers app today and then give us your feedback. The app is also available in the following languages: Bahasa Indonesia, Deutsch, español (Latinoamérica), le français, português do Brasil, tiếng Việt, русский язы́к, 한국어, 中文 (简体), 中文 (繁體), and 日本語.

This is the second app we’ve released for Google Play developers. Get the Google Play Developer Console app to review your app's performance statistics and financial data, get notified about your app's status and publishing changes, and read and reply to user reviews on the go.

Categories: Programming

Unix: Find files greater than date

Mark Needham - Fri, 06/24/2016 - 17:56

For the latter part of the week I’ve been running some tests against Neo4j which generate a bunch of log files and I wanted to filter those files based on the time they were created to do some further analysis.

This is an example of what the directory listing looks like:

$ ls -alh foo/database-agent-*
-rw-r--r--  1 markneedham  wheel   2.5K 23 Jun 14:00 foo/database-agent-mac17f73-1-logs-archive-201606231300176.tar.gz
-rw-r--r--  1 markneedham  wheel   8.6K 23 Jun 11:49 foo/database-agent-mac19b6b-1-logs-archive-201606231049507.tar.gz
-rw-r--r--  1 markneedham  wheel   8.6K 23 Jun 11:49 foo/database-agent-mac1f427-1-logs-archive-201606231049507.tar.gz
-rw-r--r--  1 markneedham  wheel   2.5K 23 Jun 14:00 foo/database-agent-mac29389-1-logs-archive-201606231300176.tar.gz
-rw-r--r--  1 markneedham  wheel    11K 23 Jun 13:44 foo/database-agent-mac3533f-1-logs-archive-201606231244152.tar.gz
-rw-r--r--  1 markneedham  wheel   4.8K 23 Jun 14:00 foo/database-agent-mac35563-1-logs-archive-201606231300176.tar.gz
-rw-r--r--  1 markneedham  wheel   3.8K 23 Jun 13:44 foo/database-agent-mac35f7e-1-logs-archive-201606231244165.tar.gz
-rw-r--r--  1 markneedham  wheel   4.8K 23 Jun 14:00 foo/database-agent-mac40798-1-logs-archive-201606231300176.tar.gz
-rw-r--r--  1 markneedham  wheel    12K 23 Jun 13:44 foo/database-agent-mac490bf-1-logs-archive-201606231244151.tar.gz
-rw-r--r--  1 markneedham  wheel   2.5K 23 Jun 14:00 foo/database-agent-mac5f094-1-logs-archive-201606231300189.tar.gz
-rw-r--r--  1 markneedham  wheel   5.8K 23 Jun 14:00 foo/database-agent-mac636b8-1-logs-archive-201606231300176.tar.gz
-rw-r--r--  1 markneedham  wheel   9.5K 23 Jun 11:49 foo/database-agent-mac7e165-1-logs-archive-201606231049507.tar.gz
-rw-r--r--  1 markneedham  wheel   2.7K 23 Jun 11:49 foo/database-agent-macab7f1-1-logs-archive-201606231049507.tar.gz
-rw-r--r--  1 markneedham  wheel   2.8K 23 Jun 13:44 foo/database-agent-macbb8e1-1-logs-archive-201606231244151.tar.gz
-rw-r--r--  1 markneedham  wheel   3.1K 23 Jun 11:49 foo/database-agent-macbcbe8-1-logs-archive-201606231049520.tar.gz
-rw-r--r--  1 markneedham  wheel    13K 23 Jun 13:44 foo/database-agent-macc8177-1-logs-archive-201606231244152.tar.gz
-rw-r--r--  1 markneedham  wheel   3.8K 23 Jun 13:44 foo/database-agent-maccd92c-1-logs-archive-201606231244151.tar.gz
-rw-r--r--  1 markneedham  wheel   3.9K 23 Jun 13:44 foo/database-agent-macdf24f-1-logs-archive-201606231244165.tar.gz
-rw-r--r--  1 markneedham  wheel   3.1K 23 Jun 11:49 foo/database-agent-mace075e-1-logs-archive-201606231049520.tar.gz
-rw-r--r--  1 markneedham  wheel   3.1K 23 Jun 11:49 foo/database-agent-mace8859-1-logs-archive-201606231049507.tar.gz

I wanted to split the files in half so that I could have the ones created before and after 12pm on the 23rd June.

I discovered that this type of filtering is actually quite easy to do with the ‘find’ command. So if I want to get the files after 12pm I could write the following:

$ find foo -name database-agent* -newermt "Jun 23, 2016 12:00" -ls
121939705        8 -rw-r--r--    1 markneedham      wheel                2524 23 Jun 14:00 foo/database-agent-mac17f73-1-logs-archive-201606231300176.tar.gz
121939704        8 -rw-r--r--    1 markneedham      wheel                2511 23 Jun 14:00 foo/database-agent-mac29389-1-logs-archive-201606231300176.tar.gz
121934591       24 -rw-r--r--    1 markneedham      wheel               11294 23 Jun 13:44 foo/database-agent-mac3533f-1-logs-archive-201606231244152.tar.gz
121939707       16 -rw-r--r--    1 markneedham      wheel                4878 23 Jun 14:00 foo/database-agent-mac35563-1-logs-archive-201606231300176.tar.gz
121934612        8 -rw-r--r--    1 markneedham      wheel                3896 23 Jun 13:44 foo/database-agent-mac35f7e-1-logs-archive-201606231244165.tar.gz
121939708       16 -rw-r--r--    1 markneedham      wheel                4887 23 Jun 14:00 foo/database-agent-mac40798-1-logs-archive-201606231300176.tar.gz
121934589       24 -rw-r--r--    1 markneedham      wheel               12204 23 Jun 13:44 foo/database-agent-mac490bf-1-logs-archive-201606231244151.tar.gz
121939720        8 -rw-r--r--    1 markneedham      wheel                2510 23 Jun 14:00 foo/database-agent-mac5f094-1-logs-archive-201606231300189.tar.gz
121939706       16 -rw-r--r--    1 markneedham      wheel                5912 23 Jun 14:00 foo/database-agent-mac636b8-1-logs-archive-201606231300176.tar.gz
121934588        8 -rw-r--r--    1 markneedham      wheel                2895 23 Jun 13:44 foo/database-agent-macbb8e1-1-logs-archive-201606231244151.tar.gz
121934590       32 -rw-r--r--    1 markneedham      wheel               13427 23 Jun 13:44 foo/database-agent-macc8177-1-logs-archive-201606231244152.tar.gz
121934587        8 -rw-r--r--    1 markneedham      wheel                3882 23 Jun 13:44 foo/database-agent-maccd92c-1-logs-archive-201606231244151.tar.gz
121934611        8 -rw-r--r--    1 markneedham      wheel                3970 23 Jun 13:44 foo/database-agent-macdf24f-1-logs-archive-201606231244165.tar.gz

And to get the ones before 12pm:

$ find foo -name database-agent* -not -newermt "Jun 23, 2016 12:00" -ls
121879391       24 -rw-r--r--    1 markneedham      wheel                8856 23 Jun 11:49 foo/database-agent-mac19b6b-1-logs-archive-201606231049507.tar.gz
121879394       24 -rw-r--r--    1 markneedham      wheel                8772 23 Jun 11:49 foo/database-agent-mac1f427-1-logs-archive-201606231049507.tar.gz
121879390       24 -rw-r--r--    1 markneedham      wheel                9702 23 Jun 11:49 foo/database-agent-mac7e165-1-logs-archive-201606231049507.tar.gz
121879393        8 -rw-r--r--    1 markneedham      wheel                2812 23 Jun 11:49 foo/database-agent-macab7f1-1-logs-archive-201606231049507.tar.gz
121879413        8 -rw-r--r--    1 markneedham      wheel                3144 23 Jun 11:49 foo/database-agent-macbcbe8-1-logs-archive-201606231049520.tar.gz
121879414        8 -rw-r--r--    1 markneedham      wheel                3131 23 Jun 11:49 foo/database-agent-mace075e-1-logs-archive-201606231049520.tar.gz
121879392        8 -rw-r--r--    1 markneedham      wheel                3130 23 Jun 11:49 foo/database-agent-mace8859-1-logs-archive-201606231049507.tar.gz

Or we could even find the ones last modified between 12pm and 2pm:

$ find foo -name database-agent* -not -newermt "Jun 23, 2016 14:00" -newermt "Jun 23, 2016 12:00" -ls
121934591       24 -rw-r--r--    1 markneedham      wheel               11294 23 Jun 13:44 foo/database-agent-mac3533f-1-logs-archive-201606231244152.tar.gz
121934612        8 -rw-r--r--    1 markneedham      wheel                3896 23 Jun 13:44 foo/database-agent-mac35f7e-1-logs-archive-201606231244165.tar.gz
121934589       24 -rw-r--r--    1 markneedham      wheel               12204 23 Jun 13:44 foo/database-agent-mac490bf-1-logs-archive-201606231244151.tar.gz
121934588        8 -rw-r--r--    1 markneedham      wheel                2895 23 Jun 13:44 foo/database-agent-macbb8e1-1-logs-archive-201606231244151.tar.gz
121934590       32 -rw-r--r--    1 markneedham      wheel               13427 23 Jun 13:44 foo/database-agent-macc8177-1-logs-archive-201606231244152.tar.gz
121934587        8 -rw-r--r--    1 markneedham      wheel                3882 23 Jun 13:44 foo/database-agent-maccd92c-1-logs-archive-201606231244151.tar.gz
121934611        8 -rw-r--r--    1 markneedham      wheel                3970 23 Jun 13:44 foo/database-agent-macdf24f-1-logs-archive-201606231244165.tar.gz

Or we can filter by relative time e.g. to find the files last modified in the last 1 day, 5 hours:

$ find foo -name database-agent* -mtime -1d5h -ls
121939705        8 -rw-r--r--    1 markneedham      wheel                2524 23 Jun 14:00 foo/database-agent-mac17f73-1-logs-archive-201606231300176.tar.gz
121939704        8 -rw-r--r--    1 markneedham      wheel                2511 23 Jun 14:00 foo/database-agent-mac29389-1-logs-archive-201606231300176.tar.gz
121934591       24 -rw-r--r--    1 markneedham      wheel               11294 23 Jun 13:44 foo/database-agent-mac3533f-1-logs-archive-201606231244152.tar.gz
121939707       16 -rw-r--r--    1 markneedham      wheel                4878 23 Jun 14:00 foo/database-agent-mac35563-1-logs-archive-201606231300176.tar.gz
121934612        8 -rw-r--r--    1 markneedham      wheel                3896 23 Jun 13:44 foo/database-agent-mac35f7e-1-logs-archive-201606231244165.tar.gz
121939708       16 -rw-r--r--    1 markneedham      wheel                4887 23 Jun 14:00 foo/database-agent-mac40798-1-logs-archive-201606231300176.tar.gz
121934589       24 -rw-r--r--    1 markneedham      wheel               12204 23 Jun 13:44 foo/database-agent-mac490bf-1-logs-archive-201606231244151.tar.gz
121939720        8 -rw-r--r--    1 markneedham      wheel                2510 23 Jun 14:00 foo/database-agent-mac5f094-1-logs-archive-201606231300189.tar.gz
121939706       16 -rw-r--r--    1 markneedham      wheel                5912 23 Jun 14:00 foo/database-agent-mac636b8-1-logs-archive-201606231300176.tar.gz
121934588        8 -rw-r--r--    1 markneedham      wheel                2895 23 Jun 13:44 foo/database-agent-macbb8e1-1-logs-archive-201606231244151.tar.gz
121934590       32 -rw-r--r--    1 markneedham      wheel               13427 23 Jun 13:44 foo/database-agent-macc8177-1-logs-archive-201606231244152.tar.gz
121934587        8 -rw-r--r--    1 markneedham      wheel                3882 23 Jun 13:44 foo/database-agent-maccd92c-1-logs-archive-201606231244151.tar.gz
121934611        8 -rw-r--r--    1 markneedham      wheel                3970 23 Jun 13:44 foo/database-agent-macdf24f-1-logs-archive-201606231244165.tar.gz

Or the ones modified more than 1 day, 5 hours ago:

$ find foo -name database-agent* -mtime +1d5h -ls
121879391       24 -rw-r--r--    1 markneedham      wheel                8856 23 Jun 11:49 foo/database-agent-mac19b6b-1-logs-archive-201606231049507.tar.gz
121879394       24 -rw-r--r--    1 markneedham      wheel                8772 23 Jun 11:49 foo/database-agent-mac1f427-1-logs-archive-201606231049507.tar.gz
121879390       24 -rw-r--r--    1 markneedham      wheel                9702 23 Jun 11:49 foo/database-agent-mac7e165-1-logs-archive-201606231049507.tar.gz
121879393        8 -rw-r--r--    1 markneedham      wheel                2812 23 Jun 11:49 foo/database-agent-macab7f1-1-logs-archive-201606231049507.tar.gz
121879413        8 -rw-r--r--    1 markneedham      wheel                3144 23 Jun 11:49 foo/database-agent-macbcbe8-1-logs-archive-201606231049520.tar.gz
121879414        8 -rw-r--r--    1 markneedham      wheel                3131 23 Jun 11:49 foo/database-agent-mace075e-1-logs-archive-201606231049520.tar.gz
121879392        8 -rw-r--r--    1 markneedham      wheel                3130 23 Jun 11:49 foo/database-agent-mace8859-1-logs-archive-201606231049507.tar.gz

There are lots of other flags you can pass to find but these ones did exactly what I wanted!

Categories: Programming

Introducing Firebase Authentication

Google Code Blog - Thu, 06/23/2016 - 21:35

Originally posted on Firebase blog

Posted by Laurence Moroney, Developer Advocate and Alfonso Gómez Jordana, Associate Product Manager

For most developers, building an authentication system for your app can feel a lot like paying taxes. They are both relatively hard to understand tasks that you have no choice but doing, and could have big consequences if you get them wrong. No one ever started a company to pay taxes and no one ever built an app just so they could create a great login system. They just seem to be inescapable costs.

But now, you can at least free yourself from the auth tax. With Firebase Authentication, you can outsource your entire authentication system to Firebase so that you can concentrate on building great features for your app. Firebase Authentication makes it easier to get your users signed-in without having to understand the complexities behind implementing your own authentication system. It offers a straightforward getting started experience, optional UX components designed to minimize user friction, and is built on open standards and backed by Google infrastructure.

Implementing Firebase Authentication is relatively fast and easy. From the Firebase console, just choose from the popular login methods that you want to offer (like Facebook, Google, Twitter and email/password) and then add the Firebase SDK to your app. Your app will then be able to connect securely with the real time database, Firebase storage or to your own custom back end. If you have an auth system already, you can use Firebase Authentication as a bridge to other Firebase features.

Firebase Authentication also includes an open source UI library that streamlines building the many auth flows required to give your users a good experience. Password resets, account linking, and login hints that reduce the cognitive load around multiple login choices - they are all pre-built with Firebase Authentication UI. These flows are based on years of UX research optimizing the sign-in and sign-up journeys on Google, Youtube and Android. It includes Smart Lock for Passwords on Android, which has led to significant improvements in sign-in conversion for many apps. And because Firebase UI is open source, the interface is fully customizable so it feels like a completely natural part of your app. If you prefer, you are also free to create your own UI from scratch using our client APIs.

And Firebase Authentication is built around openness and security. It leverages OAuth 2.0 and OpenID Connect, industry standards designed for security, interoperability, and portability. Members of the Firebase Authentication team helped design these protocols and used their expertise to weave in latest security practices like ID tokens, revocable sessions, and native app anti-spoofing measures to make your app easier to use and avoid many common security problems. And code is independently reviewed by the Google Security team and the service is protected in Google’s infrastructure.

Fabulous use Firebase Auth to quickly implement sign-in

Fabulous uses Firebase Authentication to power their login system. Fabulous is a research-based app incubated in Duke University’s Center for Advanced Hindsight. Its goal is to help users to embark on a journey to reset poor habits, replacing them with healthy rituals, with the ultimate goal of improving health and well-being.

The developers of Fabulous wanted to implement an onboarding flow that was easy to use, required minimal updates, and reduced friction with the end user. They wanted an anonymous option so that users could experiment with it before signing up. They also wanted to support multiple login types, and have an option where the user sign-in flow was consistent with the look and feel of the app.

“I was able to implement auth in a single afternoon. I remember that I spent weeks before creating my own solution that I had to update each time the providers changed their API”
- Amine Laadhari, Fabulous CTO.

Malang Studio cut time-to market by months using Firebase Auth

Chu-Day is an application (available on Android and iOS) that helps couples to never forget the dates that matter most to them. It was created by the Korean firm Malang Studio, that develops character-centric, gamified lifestyle applications.

Generally, countdown and anniversary apps do not require users to sign-in, but Malang Studio wanted to make Chu-day special, and differentiate it from others by offering the ability to connect couples so they could jointly countdown to a special anniversary date. This required a sign-in feature, and in order to prevent users from dropping out, Chu-day needed to make the sign-in process seamless.

Malang Studio was able to integrate an onboarding flow in for their apps, using Facebook and Google Sign-in, in one day, without having to worry about server deployment or databases. In addition, Malang Studio has also been taking advantage of the Firebase User Management Console, which helped them develop and test their sign-in implementation as well as manage their users:

“Firebase Authentication required minimum configuration so implementing social account signup was easy and fast. User management feature provided in the console was excellent and we could easily implement our user auth system.”
- Marc Yeongho Kim, CEO / Founder from Malang Studio

For more about Firebase Authentication, visit the developers site and watch our I/O 2016 session, “Best practices for a great sign-in experience.”

Categories: Programming

Designing for Multi-Window

Android Developers Blog - Thu, 06/23/2016 - 18:10

Posted by Ian Lake, Developer Advocate

As a developer, there’s a wide range of features added in Android N to take advantage of, but when it comes to designing and building your UI, having strong multi-window support should be at the forefront.

The primary mode that users will be interacting with multi-window is through split-screen mode, which is available on both handheld devices and larger tablets. In this mode, two apps split the available screen space and the user can drag the divider between the two split screens to resize the apps. As you might imagine, this mode offers some unique design challenges beyond what was needed previously.



An even more responsive UI

The lessons learned from previous versions of Android, the mobile web, and desktop environments still apply to Android N. Designing a responsive UI is still an important first step towards an amazing multi-window experience.

A responsive UI is one that adapts to the size provided, picking the best representation of the content and the appropriate navigation patterns to make a great user experience on any device. Check out the Building a Responsive UI blog post for details on how to design and build an effective responsive UI.

Adapting your layout

As you’re designing layouts for the largest and smallest screens and everything in between, it is important to make resizing a smooth and seamless transition as mentioned in the split screen layout guidelines. If you already have a similar layout between mobile and tablet, you’ll find much of your work taken care of for you.

However, if your mobile and tablet layouts are vastly different and there’s no way to smoothly transition between the two, you should not transition between them when resizing. Instead, focus on making your tablet UI scale down using the same responsive UI patterns. This ensures that users do not have to relearn their UI when resizing your app.

Note that the minimalHeight and minimalWidth layout attributes allow you to set a minimum size you want reported to your Activity, but they do not mean the user cannot resize your activity smaller - it actually means that your activity will be cropped to the size the user requests, potentially forcing elements of your UI off the screen. Strive to support down to the minimum size of 220x220dp.

Design configurations to consider

While many of the sizes and aspect ratios possible in multi-window are similar to existing devices (1/3rd of a landscape tablet is similar to existing mobile devices in screen size), there are a few configurations that are much more common when considering multi-window.

The first is a 16x9 layout on mobile devices in portrait. In this case, the vertical space is extremely limited. If you have a number of fixed elements stacked on top of one another (a toolbar, scrolling content, and a bottom navigation bar), you might find there’s not actually any room for the scrolling content - the most important part!

The second case to consider is the 34.15% layout on tablets. The very wide aspect ratio in device portrait or very tall aspect ratio in device landscape orientation are more extreme than what is found on existing devices. Consider using your mobile layouts as a starting point for this configuration.

Patterns to avoid

When it comes to multi-window, there are a few patterns you want to avoid entirely.

The first is UI interactions that rely on swiping from the edge of the screen. This has already been somewhat of an issue when it comes to the on screen navigation bar prominent on many devices (such as Nexus devices), but is even more so in split-screen mode. Since there is (purposefully) no way to determine if your activity is on the top or bottom or the left or the right, don’t make edge swipes the only way to access functionality in your app. That doesn’t mean you have to avoid them entirely - just make sure there is an alternative. A good example of this is the temporary navigation drawer - an edge swipe opens the drawer, but it is also accessible by pressing the hamburger icon in the toolbar.

The second is disabling multi-window entirely. While there are certainly cases where this makes sense (i.e., it is fundamentally an immersive experience such as a game), there are also cases where your activity and any Activities launched from that Activity are forced to support multi-window. As mentioned in the Preparing for Multi-Window blog post, when you support external apps launching your activity, your activity inherits the multi-window properties of the calling Activity.

Designing for Multi-Window is designing for every device

Building a responsive UI that reacts to the space available is critical to a great multi-window experience, but it is an exercise that can benefit all of your users across the wide variety of Android devices.

So use this as an opportunity to #BuildBetterApps

Follow the Android Development Patterns Collection for more!

Categories: Programming

Introducing the Android Basics Nanodegree

Google Code Blog - Wed, 06/22/2016 - 22:50

Posted by Shanea King-Roberson, Lead Program Manager Twitter: @shaneakr Instagram: @theshanea


Do you have an idea for an app but you don’t know where to start? There are over 1 billion Android devices worldwide, providing a way for you to deliver your ideas to the right people at the right time. Google, in partnership with Udacity, is making Android development accessible and understandable to everyone, so that regardless of your background, you can learn to build apps that improve the lives of people around you.

Enroll in the new Android Basics Nanodegree. This series of courses and services teaches you how to build simple Android apps--even if you have little or no programming experience. Take a look at some of the apps built by our students:

The app "ROP Tutorial" built by student Arpy Vanyan raises awareness of a potentially blinding eye disorder called Retinopathy of Prematurity that can affect newborn babies.

And user Charles Tommo created an app called “Dr Malaria” that teaches people ways to prevent malaria.

With courses designed by Google, you can learn skills that are applicable to building apps that solve real world problems. You can learn at your own pace to use Android Studio(Google’s official tool for Android app development) to design app user interfaces and implement user interactions using the Java programming language.

The courses walk you through step-by-step on how to build an order form for a coffee shop, an app to track pets in a shelter, an app that teaches vocabulary words from the Native American Miwok tribe, and an app on recent earthquakes in the world. At the end of the course, you will have an entire portfolio of apps to share with your friends and family.

Upon completing the Android Basics Nanodegree, you also have the opportunity to continue your learning with the Career-track Android Nanodegree (for intermediate developers). The first 50 participants to finish the Android Basics Nanodegree have a chance to win a scholarship for the Career-track Android Nanodegree. Please visit udacity.com/legal/scholarshipfor additional details and eligibility requirements. You now have a complete learning path to help you become a technology entrepreneur or most importantly, build very cool Android apps, for yourself, your communities, and even the world.

All of the individual courses that make up this Nanodegree are available online for no charge at udacity.com/google. In addition, Udacity provides paid services, including access to coaches, guidance on your project, help staying on track, career counseling, and a certificate upon completion for a fee.

You will be exposed to introductory computer science concepts in the Java programming language, as you learn the following skills.

  • Build app user interfaces
  • Implement user interactions
  • Store information in a database
  • Pull data from the internet into your app
  • Identify and fix unexpected behavior in the app
  • Localize your app to support other languages

To enroll in the Android Basics Nanodegree program, click here.

See you in class!

Categories: Programming

Introducing the Android Basics Nanodegree

Android Developers Blog - Wed, 06/22/2016 - 18:48

Posted by Shanea King-Roberson, Lead Program Manager Twitter: @shaneakr Instagram: @theshanea


Do you have an idea for an app but you don’t know where to start? There are over 1 billion Android devices worldwide, providing a way for you to deliver your ideas to the right people at the right time. Google, in partnership with Udacity, is making Android development accessible and understandable to everyone, so that regardless of your background, you can learn to build apps that improve the lives of people around you.

Enroll in the new Android Basics Nanodegree. This series of courses and services teaches you how to build simple Android apps--even if you have little or no programming experience. Take a look at some of the apps built by our students:

The app "ROP Tutorial" built by student Arpy Vanyan raises awareness of a potentially blinding eye disorder called Retinopathy of Prematurity that can affect newborn babies.

And user Charles Tommo created an app called “Dr Malaria” that teaches people ways to prevent malaria.

With courses designed by Google, you can learn skills that are applicable to building apps that solve real world problems. You can learn at your own pace to use Android Studio (Google’s official tool for Android app development) to design app user interfaces and implement user interactions using the Java programming language.

The courses walk you through step-by-step on how to build an order form for a coffee shop, an app to track pets in a shelter, an app that teaches vocabulary words from the Native American Miwok tribe, and an app on recent earthquakes in the world. At the end of the course, you will have an entire portfolio of apps to share with your friends and family.

Upon completing the Android Basics Nanodegree, you also have the opportunity to continue your learning with the Career-track Android Nanodegree (for intermediate developers). The first 50 participants to finish the Android Basics Nanodegree have a chance to win a scholarship for the Career-track Android Nanodegree. Please visit udacity.com/legal/scholarship for additional details and eligibility requirements. You now have a complete learning path to help you become a technology entrepreneur or most importantly, build very cool Android apps, for yourself, your communities, and even the world.

All of the individual courses that make up this Nanodegree are available online for no charge at udacity.com/google. In addition, Udacity provides paid services, including access to coaches, guidance on your project, help staying on track, career counseling, and a certificate upon completion for a fee.

You will be exposed to introductory computer science concepts in the Java programming language, as you learn the following skills.

  • Build app user interfaces
  • Implement user interactions
  • Store information in a database
  • Pull data from the internet into your app
  • Identify and fix unexpected behavior in the app
  • Localize your app to support other languages

To enroll in the Android Basics Nanodegree program, click here.

See you in class!

Categories: Programming

How to Have Better Fridays

Recently, I’ve been teaching more people Agile Results. 

I teach them really fast, because I just focus on teaching them the most important tool in Agile Results:

Monday Vision, Daily Wins, Friday Reflection

But before I walk through, I share a quick story of how it all started.

Monday Vision was Born for Better Fridays

It was a warm, sunny, Friday afternoon.
My colleague and I were on our way to our favorite pizza place.
It was a beautiful day.  It should have been a great day.
But I felt like a beast of burden with the weight of the world on my back.
Our backlog was overflowing, we didn’t make it through what we thought we would, and we had been slogging away.
And for what?
Well, I caught myself looking in the rear view mirror, more than looking ahead.
Instead of feeling great, I felt like crap.
So I turned to my colleague and asked him how much we realistically have to spend on work when we get back.
We lied to each other and ourselves.  Then we got real.
We figured the best thing we could possibly do would be to prioritize the value we could deliver next week.
With that, we enjoyed our pizza, and when we got back to work, we figured out what a great next week would look like.
I never wanted us to have another Friday where we couldn’t go into weekend feeling good about what we had accomplished for the week.
And that’s how Monday Vision was born.

Monday Vision, Daily Wins, Friday Reflection for Better Fridays

One I tell that little story, people get it pretty quickly.  They’ve been there.  They feel the pain.

They slogged away all week and at the end of the week, instead of feeling good about their achievements, they feel like they haven’t done enough.

They are never done.  They are overwhelmed. 

Instead of feeling like they earned their weekend for rest and relaxation, they feel guilty that they should work on their never-ending backlog and laundry-list of To-Dos.

Monday Vision for Better Fridays

So then I walk them through how to do Monday Vision, so they can have better Fridays.

On Mondays, imagine if it were Friday.  Really step into your future Friday and feel it.   What are Three Wins you really want to have under your belt?

What would you want to be able to say to your manager or to your team or to yourself, about what you accomplished or achieved for the week?

Get clarity on that.

Use that simple story of your Three Wins that you want to be able to talk about on Friday, as your way to prioritize your focus for the week on Monday.

Now you are doing “Monday Vision.”

Daily Wins for Better Fridays

Each day, identify your Three Wins for that day.  This is the “Daily Wins” practice.

You will have those days where your Three Wins might be, “Great Breakfast,” “Great Lunch”, “Great Dinner.”

There will be days that knock you down, and you wonder how you will get back up.

But then you will also have those days where you are on top of the world and your Three Wins for today will be magnificent.

You might even say, they will be your masterpiece.

Either way, get in the habit of starting your day by identifying Three Wins you want to achieve.

That will help you focus and prioritize all that you do in a more meaningful way for results that matter.

If you don’t know how to do this, just imagine if you were closing out your day, what are Three Wins that you want to be able to say you’ve achieved, either to you, your manager, your team or that someone special.

Friday Reflection for Better Fridays

Lastly, there is Friday Reflection.

Friday Reflection is your chance to dig deep and gain some new personal productivity insights.

Ask yourself, “What are three things going well?” and ask yourself, “What are three things to improve?”

Be honest with yourself about your answers.

You are the one that will win or lose from what you learn.

This is your chance to change any long-standing patterns of your personal productivity challenges.

Do you bite off more than you can chew?  Do you get randomized during the week?

Do you have a hard time figuring out what is actually valued?

Use what you learn to feed into next week.  This is your chance to change and practice your Growth Mindset.

Don’t expect any of these exercises to be easy, but they get easier with practice.

And that’s just it.  This isn’t a one-time trick.

This is a very precise set of productivity habits and practices that you can use for your lifetime to master time management, master your energy, master your motivation, and become more of what you are capable of.

Unleash your productivity, the Agile Way.

Best wishes for better Fridays.

Categories: Architecture, Programming

How to Keep flowtype Running and Report Errors on Save

Xebia Blog - Tue, 06/21/2016 - 08:00
We use flow from Facebook to run type checking on our codebase. When you run ‘flow status’ it starts a flow server in the background and keeps it running. That way after the first run the results of each next run are almost instant. The only thing currently lacking is a watch mode, but there

Notifications in Android N

Android Developers Blog - Mon, 06/20/2016 - 20:10

Posted by Ian Lake, Developer Advocate

Android notifications are often a make-or-break interaction between your Android app and users. To provide a better user experience, notifications on Android N have received a visual refresh, improved support for custom views, and expanded functionality in the forms of Direct Reply, a new MessagingStyle, and bundled notifications.

Same notification, new look

The first and most obvious change is that the default look and feel of notifications has significantly changed. Many of the fields that were spread around the notifications have been collapsed into a new header row with your app’s icon and name anchoring the notification. This change ensured that the title, text, and large icon are given the most amount of space possible and, as a result, notifications are generally slightly larger now and easier to read.


Given the single header row, it is more important than ever that the information there is useful. When you target Android N, by default the time will be hidden - if you have a time critical notification such as a messaging app, you can re-enable it with setShowWhen(true). In addition, the subtext now supersedes the role of content info and number: number is never shown on Android N devices and only if you target a previous version of Android and don’t include a subtext will content info appear. In all cases, ensure that the subtext is relevant and useful - don’t add an account email address as your subtext if the user only has one account, for example.

Notification actions have also received a redesign and are now in a visually separate bar below the notification.


You’ll note that the icons are not present in the new notifications; instead more room is provided for the labels themselves in the constrained space of the notification shade. However, the notification action icons are still required and continue to be used on older versions of Android and on devices such as Android Wear.

If you’ve been building your notification with NotificationCompat.Builder and the standard styles available to you there, you’ll get the new look and feel by default with no code changes required. Better Support for Custom Views

If you’re instead building your notification from custom RemoteViews, adapting to any new style has been challenging. With the new header, expanding behavior, actions, and large icon positioning as separate elements from the main text+title of the notification, we’ve introduced a new DecoratedCustomViewStyle and DecoratedMediaCustomViewStyle to provide all of these elements, allowing you to focus only on the content portion with the new setCustomContentView() method.


This also ensures that future look and feel changes should be significantly easier to adapt to as these styles will be updated alongside the platform with no code changes needed on the app side.

Direct Reply

While notification actions have already been able to launch an Activity or do background work with a Service or BroadcastReceiver, Direct Reply allows you to build an action that directly receives text input inline with the notification actions.


Direct Reply uses the same RemoteInput API - originally introduced for Android Wear - to mark an Action as being able to directly receive input from the user.

The RemoteInput itself contains information like the key which will be used to later retrieve the input and the hint text which is displayed before the user starts typing.

// Where should direct replies be put in the intent bundle (can be any string)
private static final String KEY_TEXT_REPLY = "key_text_reply";

// Create the RemoteInput specifying this key
String replyLabel = getString(R.string.reply_label);
RemoteInput remoteInput = new RemoteInput.Builder(KEY_TEXT_REPLY)
        .setLabel(replyLabel)
        .build();


Once you’ve constructed the RemoteInput, it can be attached to your Action via the aptly named addRemoteInput() method. You might consider also calling setAllowGeneratedReplies(true) to enable Android Wear 2.0 to generate Smart Reply choices when available and make it easier for users to quickly respond.

// Add to your action, enabling Direct Reply for it
NotificationCompat.Action action =
    new NotificationCompat.Action.Builder(R.drawable.reply, replyLabel, pendingIntent)
        .addRemoteInput(remoteInput)
        .setAllowGeneratedReplies(true)
        .build();


Keep in mind that the pendingIntent being passed into your Action should be an Activity on Marshmallow and lower devices that don’t support Direct Reply (as you’ll want to dismiss the lock screen, start an Activity, and focus the input field to have the user type their reply) and should be a Service (if you need to do work on a separate thread) or BroadcastReceiver (which runs on the UI thread) on Android N devices so as the process the text input in the background even from the lock screen. (There is a separate user control to enable/disable Direct Reply from a locked device in the system settings.)

Extracting the text input in your Service/BroadcastReceiver is then possible with the help of the RemoteInput.getResultsFromIntent() method:

private CharSequence getMessageText(Intent intent) {
    Bundle remoteInput = RemoteInput.getResultsFromIntent(intent);
    if (remoteInput != null) {
        return remoteInput.getCharSequence(KEY_TEXT_REPLY);
    }
    return null;
 }


After you’ve processed the text, you must update the notification. This is the trigger which hides the Direct Reply UI and should be used as a technique to confirm to the user that their reply was received and processed correctly.

For most templates, this should involve using the new setRemoteInputHistory() method which appends the reply to the bottom of the notification. Additional replies should be appended to the history until the main content is updated (such as the other person replying).


However, if you’re building a messaging app and expect back and forth conversations, you should use MessagingStyle and append the additional message to it.

MessagingStyle

We’ve optimized the experience for displaying an ongoing conversation and using Direct Reply with the new MessagingStyle.


This style provides built-in formatting for multiple messages added via the addMessage() method. Each message supports passing in the text itself, a timestamp, and the sender of the message (making it easy to support group conversations).

builder.setStyle(new NotificationCompat.MessagingStyle("Me")
    .setConversationTitle("Team lunch")
    .addMessage("Hi", timestampMillis1, null) // Pass in null for user.
    .addMessage("What's up?", timestampMillis2, "Coworker")
    .addMessage("Not much", timestampMillis3, null)
    .addMessage("How about lunch?", timestampMillis4, "Coworker"));


You’ll note that this style has first-class support for specifically denoting messages from the user and filling in their name (in this case with “Me”) and setting an optional conversation title. While this can be done manually with a BigTextStyle, by using this style Android Wear 2.0 users will get immediate inline responses without kicking them out of the expanded notification view, making for a seamless experience without needing to build a full Wear app.

Bundled Notifications

Once you’ve built a great notification by using the new visual designs, Direct Reply, MessagingStyle, and all of our previous best practices, it is important to think about the overall notification experience, particularly if you post multiple notifications (say, one per ongoing conversation or per new email thread).


Bundled notifications offer the best of both worlds: a single summary notification for when users are looking at other notifications or want to act on all notifications simultaneously and the ability to expand the group to act on individual notifications (including using actions and Direct Reply).

If you’ve built stacking notifications for Android Wear, the API used here is exactly the same. Simply add setGroup() to each individual notification to bundle those notifications together. You’re not limited to one group, so bundle notifications appropriately. For an email app, you might consider one bundle per account for instance.

It is important to also create a summary notification. This summary notification, denoted by setGroupSummary(true), is the only notification that appears on Marshmallow and lower devices and should (you guessed it) summarize all of the individual notifications. This is an opportune time to use the InboxStyle, although using it is not a requirement. On Android N and higher devices, some information (such as the subtext, content intent, and delete intent) is extracted from the summary notification to produce the collapsed notification for the bundled notifications so you should continue to generate a summary notification on all API levels.

To improve the overall user experience on Android N devices, posting 4 or more notifications without a group will cause those notifications to be automatically bundled.

N is for Notifications

Notifications on Android have been a constant area of progressive enhancement. From the single tap targets of the Gingerbread era to expandable notifications, actions, MediaStyle, and now features such as Direct Reply and bundled notifications, notifications play an important part of the overall user experience on Android.

With many new tools to use (and NotificationCompat to help with backward compatibility), I’m excited to see how you use them to #BuildBetterApps

Follow the Android Development Patterns Collection for more!

Categories: Programming

Unix: Find all text below string in a file

Mark Needham - Sun, 06/19/2016 - 09:36

I recently wanted to parse some text out of a bunch of files so that I could do some sentiment analysis on it. Luckily the text I want is at the end of the file and doesn’t have anything after it but there is text before it that I want to get rid.

The files look like this:

# text I don't care about
 
= Heading of the bit I care about
 
# text I care about

In other words I want to find the line that contains the Heading and then get all the text after that point.

I figured sed was the tool for the job but my knowledge of the syntax was a bit rusty. Luckily this post served as a refresher.

Effectively what we want to do is delete from the beginning of the file up until the line after the heading. We can do this with the following command:

$ cat /tmp/foo.txt 
# text I don't care about
 
= Heading of the bit I care about
 
# text I care about
$ cat /tmp/foo.txt | sed '1,/Heading of the bit I care about/d'
 
# text I care about

That still leaves an extra empty line after the heading which is a bit annoying but easy enough to get rid of by passing another command to sed that strips empty lines:

$ cat /tmp/foo.txt | sed -e '1,/Heading of the bit I care about/d' -e '/^\s*$/d'
# text I care about

The only difference here is that we’re now passing the ‘-e’ flag to allow us to specify multiple commands. If we just pass them sequentially then the 2nd one will be interpreted as the name of a file.

Categories: Programming

Unix: Split string using separator

Mark Needham - Sun, 06/19/2016 - 08:22

I recently found myself needing to iterate over a bunch of ‘/’ separated strings on the command line and extract just the text after the last ‘/’.

e.g. an example of one of the strings

A/B/C

I wanted to write some code that could split on ‘/’ and then pick the 3rd item in the resulting collection.

One way of doing this is to echo the string and then pipe it through cut:

$ string="A/B/C"
$ echo ${string} | cut -d"/" -f3
C

or awk:

$ echo ${string} | awk -F"/" '{ print $3}'
C

I don’t like having to echo the string – it feels a bit odd so I wanted to see if there was a way to do the parsing more ‘inline’.

I came across this post which explains how to change the internal field separator (IFS) on the shell and then parse the string into an array using read. I gave it a try:

$ IFS="/" read -ra ADDR <<< "${string}"; echo ${ADDR[2]}
C

Works! We can even refer to the last item in the array using -1 instead of it’s absolute position:

$ IFS="/" read -ra ADDR <<< "${string}"; echo ${ADDR[-1]}
C

I’d not come across this use of the ‘read’ function before. The key is the ‘-a’ parameter. From the man page:

-a aname
The words are assigned to sequential indices of the array variable aname,
starting at 0. All elements are removed from aname before the assignment.
Other name arguments are ignored.

So we’re resetting the internal field separator and then reading the string into another variable as an array split on the ‘/’ character.

Pretty neat although now it’s longer than the original command and I’m sure I’ll forget the syntax.

Further down the page is another suggestion which seems even harder to remember but is much shorter:

$ echo ${string##*/} 
C

This drops from the beginning of the string up until the last occurrence of ‘/’ which is exactly what we want.

This way is the nicest and doesn’t require any echoing if we just want to assign the result to a variable. The echo is only used here to see the output.

Categories: Programming

Android N APIs are now final, get your apps ready for Android N!

Android Developers Blog - Sun, 06/19/2016 - 02:41

Posted by Dave Burke, VP of Engineering

As we put the finishing touches on the next release of Android, which will begin to roll out to consumers later this summer, we’re releasing the 4th Developer Preview of Android N, including the Android N final SDK. And thanks to your continued feedback over the last three releases, all of the APIs are now final as well. If you’ve already enrolled your device in the Android Beta Program, (available at android.com/beta) you will receive an update to this Developer Preview shortly.

Get your apps ready for Android N

The final SDK for Android N is now available for download through the SDK Manager in Android Studio. It gives you everything you need to develop and test against the official APIs in the Android N platform. Once you’ve installed the final SDK, you can update your project’s compileSdkVersion to API 24 to develop with the Android N APIs and build and test on the new platform, for new features such as Multi-window support, direct-reply notifications, and others. We also recommend updating your app’s targetSdkVersion to API 24 to opt-in and test your app with Android N specific behavior changes. For details on how to setup your app with the final SDK, see Set up the Preview. For details on API level 24 check out the API diffs and the updated API reference, now hosted online.

Along with the Android N final SDK, we’ve also updated the Android Support Library to 24.0.0. This allows you to use multi-window and picture-in-picture callbacks, new notification features, methods for supporting Direct Boot, and new MediaBrowser APIs in a backward compatible manner.

Publish your apps to alpha, beta or production channels in Google Play

Now that you have a final set of APIs, you can publish updates compiling with, and optionally targeting, API 24 to Google Play. You can now publish app updates that use API 24 to your alpha, beta, or even production channels in the Google Play Developer Console. In this way, you can test your app’s backward-compatibility and push updates to users whose devices are running Developer Preview 4.

To make sure that your updated app runs well on Android N, as well as older versions, a common strategy is to use Google Play’s beta testing feature to get early feedback from a small group of users -- including developer preview users — and then do a staged rollout as you release the updated app to all users.

How to Get Developer Preview 4

Developer Preview 4 includes updated system images for all supported Preview devices as well as for the Android emulator. If you are already enrolled in the Android Beta program, your devices will get the Developer Preview 4 update right away, no action is needed on your part. If you aren’t yet enrolled in Android Beta, the easiest way to get started is by visiting android.com/beta and opt-in your eligible Android phone or tablet -- you’ll soon receive this (and later) preview updates over-the-air. As always, you can also download and flash this update manually. The N Developer Preview is available for Nexus 6, Nexus 5X, Nexus 6P, Nexus 9, and Pixel C devices, as well as General Mobile 4G [Android One] devices and the Sony Xperia Z3.

Thanks so much for all of your feedback so far. Please continue to share feedback or requests either in the N Developer Preview issue tracker, N Preview Developer community, or Android Beta community as we work towards the consumer release later this summer. We’re looking forward to seeing your apps on Android N!

Categories: Programming