Lint is a static checker which analyzes Android projects for a variety of issues around correctness, security, performance, usability and accessibility, checking your XML resources, bitmaps, ProGuard configuration files, source files and even compiled bytecode. It can be run from within Eclipse or from the command line.
New for r17:

• Added check for Android API calls that require a version of Android higher than the minimum supported version. You can use the new @TargetApi annotation to specify local overrides for conditionally loaded code. For more information, read here.
• Added over 40 new Lint rules for a total of over 80, including checks for performance, XML layouts, manifest and file handling. For a full list read here.
• Added ability to suppress Lint warnings in Java code with the new @SuppressLint annotation, and in XML files with the new tools: namespace prefix and ignore attribute. For more information, read here.
• Improved HTML and XML reporting and Eclipse integration. For more information, read here.

We’ve also made improvements to the build systems for Eclipse and Ant:

• Added strict dependency support for 3rd party Jar files. You can read more information here.
• Added support for custom views with custom attributes in libraries. Layouts using custom attributes must use the namespace URI http://schemas.android.com/apk/res-auto instead of the URI that includes the app package name. This URI is replaced with the app specific one at build time.
• Added a feature that allows you to run some code only in debug mode. Builds now generate a class called BuildConfig containing a DEBUG constant that is automatically set according to your build type. You can check the (BuildConfig.DEBUG) constant in your code to run debug-only functions such as outputting debug logs.

The emulator is seeing some big improvements as well:

• Thanks to contributions to AOSP from Intel, the emulator now supports running x86 system images in virtualization mode on Windows and Mac OS X. This allows the emulator running at near native speed. The drivers are available through the SDK Manager. Read more here.
• After adding webcam support and sensor emulation, we are adding experimental support for Multi-Touch input through a tethered Android device. (Read more here)

Finally, we are also releasing an updated Support Library with the following improvements:

• ShareCompat provides easy helper classes for both sending and receiving content for social sharing apps.
• NavUtils and TaskStackBuilder provide cross-version support for implementing the Android Design guidelines for navigating within your app including the action bar's "Up" button.
• NotificationCompat.Builder provides a compatibility implementation of Android 3.0's Notification.Builder helper class for creating standardized system notifications.
• A new Library Project adds support for GridLayout back to API level 7 and higher.

You can get more information about these changes in the SDK Tools Release Notes and ADT Release Notes.

Some of the new APIs in Android 4.0.3 include:

Social stream API in Contacts provider: Applications that use social stream data such as status updates and check-ins can now sync that data with each of the user’s contacts, providing items in a stream along with photos for each. This new API lets apps show users what the people they know are doing or saying, in addition to their photos and contact information.

Calendar provider enhancements. Apps can now add color to events, for easier tracking, and new attendee types and states are now available.

New camera capabilities. Apps can now check and manage video stabilization and use QVGA resolution profiles where needed.

Accessibility refinements. Improved content access for screen readers and new status and error reporting for text-to-speech engines.

Incremental improvements in graphics, database, spell-checking, Bluetooth, and more.

For a complete overview of what’s new in the platform, see the Android 4.0.3 API Overview.

Going forward, we’ll be focusing our partners on Android 4.0.3 as the base version of Ice Cream Sandwich. The new platform will be rolling out to production phones and tablets in the weeks ahead, so we strongly encourage you to test your applications on Android 4.0.3 as soon as possible.

We would also like to remind developers that we recently released new version of the SDK Tools (r16) and of the Eclipse plug-in (ADT 16.0.1). We have also updated the NDK to r7.

Visit the Android Developers site for more information about Android 4.0.3 and other platform versions. To get started developing or testing on the new platform, you can download it into your SDK using the Android SDK Manager.

Android NDK r7 includes a number of build system improvements and bug fixes, but most importantly it gives you access to two new sets of APIs:

For detailed information about how to use these new APIs, please see the documentation included with the Android NDK r7 package. To read about the build system improvements and bug fixes included in this release, check out the release notes.

Previously, library projects were handled as extra resource and source code folders to be used when compiling the resources and the application’s source respectively. While this worked fine for most cases, there were two issues.

1. Developers asked us for the ability to distribute a library as a single jar file that included both compiled code and resources. The nature of Android resources, with their compiled IDs prevented this.

2. The implementation of the library projects was extremely fragile in Eclipse. Adding extra source folders outside of the project folders is non-trivial when it needs to be handled automatically, in a way that doesn’t expose a user’s local installation path (which is required for people working in teams through a source control system such as SVN or git).

For r14, we decided to fix both issues at once, by moving to a compiled-code based library mechanism. This solves the implementation fragility in Eclipse and will allow us to, later, enable distribution of libraries as a single jar file.

As you might have seen in the release notes, moving to this new mechanism can affect existing projects in some cases, but there are simple fixes.

The first impact of this change is that the new library project requires the resource IDs generated by libraries to be non final. This prevents the Java compiler from inlining the values in the library code, and therefore prevents usage of the switch statement in the library code. To address such occurrences in your code, Eclipse provides a refactoring action to convert from switch statements to if/else (see here).

Second, some projects may not have been properly migrated to the new mechanism, resulting in projects that fail to compile, with errors such as duplicated classes being added in the dex build step. ADT 14 should have migrated older projects to the new mechanism but the fragility of the old mechanism may have prevented it from happening. This makes projects reference the libraries twice, using both the old and new mechanisms, which then triggers the libraries classes being packaged twice. If you see this in your projects, look in the Package Explorer for extraneous source folders named with the pattern <libraryname>_src. The screenshot to the right shows an example of this.

To fix the project, you must remove the extraneous source folders with the following steps:

• Right click source folder and choose Build Path > Remove from Build path
• A dialog will pop up. In it, make sure to check “Also unlink the folder from the project” to completely remove the folder.

With this change to library projects, we pave the way to better support for reusable components. We will continue working to make components easier to create, work with, and manage. Our goal is to make it easy for developers to create apps with great user experiences that easily adapt to all form factors.

Some developers have also told us that they only use library projects internally, that they don’t need to distribute binary versions and would prefer to continue with a source-based mechanism. We are investigating how we could support this alongside the new mechanism.

Finally, I wanted to point out that we are tracking a few known issues (and workaround for them) in the current r14 tools at this page: http://tools.android.com/knownissues.

We are working on a tools update that will include fixes for most of these. We are hoping to have it out shortly.

Today we are announcing Android 4.0, Ice Cream Sandwich — a new version of the platform that brings a refined, unified user experience for phones, tablets, and more.

Android 4.0 builds on the things people love most about Android — efficient multitasking, rich notifications, customizable home screens, resizable widgets, and deep interactivity — and adds powerful new ways of communicating and sharing. It includes many great features for users, including social and sharing integration, network data usage control, innovative connectivity and camera options, and an updated set of standard apps.

For developers, Android 4.0 introduces many new capabilities and APIs. Here are some highlights:

For a complete overview of what’s new for users and developers, please read the Android 4.0 Platform Highlights.

Alongside the new Android platform, we are releasing new versions of the SDK Tools (r14) and ADT Plugin (14.0) for Eclipse. Among the highlights are:

• Improved build performance in Ant and Eclipse
• Improved layout and XML editors

To get started developing on Android 4.0, visit the Android Developers site for information about the Android 4.0 platform, the SDK Tools, and the ADT Plugin.

If you have already developed and published apps, we encourage you to download the Android 4.0 platform now, to begin testing your app before devices arrive in stores.

Check out the video below for a closer look at Android 4.0 in action.

Here are some of the highlights of Android 3.2:

For a complete overview of what’s new in the platform, see the Android 3.2 Version Notes.

We would also like to remind developers that we recently released new version of the SDK Tools (r12) and of the Eclipse plug-in (ADT 12). We have also updated the NDK to r6.

Visit the Android Developers site for more information about Android 3.2 and other platform versions. To get started developing or testing on the new platform, you can download it into your SDK using the Android SDK Manager.

ADT 11 focuses on editor improvements. First, it offers several new visual refactoring operations, such as “Extract Include” and “Extract Style,” which help automatically extract duplicated layout fragments and style attributes into reusable layouts, styles, and themes.

Second, the visual layout editor now supports fragments, palette configurations, and improved support for custom views.

Last, XML editing has been improved with new quick fixes, code completion in more file types and many “go to declaration” enhancements.

ADT 11 packs a long list of new features and enhancements. Please visit our ADT page for more details. For an in-depth demo, check out the video of our Android Development Tools session at Google I/O, below.

Please note that the visual layout editor depends on a layout rendering library that ships with each version of the platform component in the SDK. We are currently working on a number of improvements to this library as well, which we plan to release soon for all platform versions. When we release the updates, some new features in ADT 11 will be “unlocked” - such as support for ListView previewing - so keep an eye on this blog for further announcements.

• Open Accessory API. This new API provides a way for Android applications to integrate and interact with a wide range of accessories such as musical equipment, exercise equipment, robotics systems, and many others.
• USB host API. On devices that support USB host mode, applications can now manage connected USB peripherals such as audio devices. input devices, communications devices, and more.
• Input from mice, joysticks, and gamepads. Android 3.1 extends the input event system to support a variety of new input sources and motion events such as from mice, trackballs, joysticks, gamepads, and others.
• Resizable Home screen widgets. Developers can now create Home screen widgets that are resizeable horizontally, vertically, or both.
• Media Transfer Protocol (MTP) Applications can now receive notifications when external cameras are attached and removed, manage files and storage on those devices, and transfer files and metadata to and from them.
• Real-time Transport Protocol (RTP) API for audio. Developers can directly manage on-demand or interactive data streaming to enable VOIP, push-to-talk, conferencing, and audio streaming.

For a complete overview of what’s new in the platform, see the Android 3.1 Platform Highlights.

To make the Open Accessory API available to a wide variety of devices, we have backported it to Android 2.3.4 as an optional library. Nexus S is the first device to offer support for this feature. For developers, the 2.3.4 version of the Open Accessory API is available in the updated Google APIs Add-On.

Alongside the new platforms, we are releasing an update to the SDK Tools (r11).

Visit the Android Developers site for more information about Android 3.1, Android 2.3.4, and the updated SDK tools. To get started developing or testing on the new platforms, you can download them into your SDK using the Android SDK Manager.

Besides the user-facing features it offers, Android 3.0 is also specifically designed to give developers the tools and capabilities they need to create great applications for tablets and similar devices, together with the flexibility to adapt existing apps to the new UI while maintaining compatibility with earlier platform versions and other form-factors.

Today, we are releasing a preview of the Android 3.0 SDK, with non-final APIs and system image, to allow developers to start testing their existing applications on the tablet form-factor and begin getting familiar with the new UI patterns, APIs, and capabilties that will be available in Android 3.0.

Here are some of the highlights:

UI framework for creating great apps for larger screen devices: Developers can use a new UI components, new themes, richer widgets and notifications, drag and drop, and other new features to create rich and engaging apps for users on larger screen devices.

High-performance 2D and 3D graphics: A new property-based animation framework lets developers add great visual effects to their apps. A built-in GL renderer lets developers request hardware-acceleration of common 2D rendering operations in their apps, across the entire app or only in specific activities or views. For adding rich 3D scenes, developers take advantage of a new 3D graphics engine called Renderscript.

Support for multicore processor architectures: Android 3.0 is optimized to run on either single- or dual-core processors, so that applications run with the best possible performance.

Rich multimedia: New multimedia features such as HTTP Live streaming support, a pluggable DRM framework, and easy media file transfer through MTP/PTP, give developers new ways to bring rich content to users.

New types of connectivity: New APIs for Bluetooth A2DP and HSP let applications offer audio streaming and headset control. Support for Bluetooth insecure socket connection lets applications connect to simple devices that may not have a user interface.

Enhancements for enterprise: New administrative policies, such as for encrypted storage and password expiration, help enterprise administrators manage devices more effectively.

For an complete overview of the new user and developer features, see the Android 3.0 Platform Highlights.

Additionally, we are releasing updates to our SDK Tools (r9), NDK (r5b), and ADT Plugin for Eclipse (9.0.0). Key features include:

• UI Builder improvements in the ADT Plugin:
  • Improved drag-and-drop in the editor, with better support for included layouts.
  • In-editor preview of objects animated with the new animation framework.
  • Visualization of UI based on any version of the platform. independent of project target. Improved rendering, with better support for custom views.

To find out how to get started developing or testing applications using the Android 3.0 Preview SDK, see the Preview SDK Introduction. Details about the changes in the latest versions of the tools are available on the SDK Tools, the ADT Plugin, and NDK pages on the site.

Note that applications developed with the Android 3.0 Platform Preview cannot be published on Android Market. We’ll be releasing a final SDK in the weeks ahead that you can use to build and publish applications for Android 3.0.

Enhancements for game development: To improve overall responsiveness, we’ve added a new concurrent garbage collector and optimized the platform’s overall event handling. We’ve also given developers native access to more parts of the system by exposing a broad set of native APIs. From native code, applications can now access input and sensor events, EGL/OpenGL ES, OpenSL ES, and assets, as well a new framework for managing lifecycle and windows. For precise motion processing, developers can use several new sensor types, including gyroscope.

Rich multimedia: To provide a great multimedia environment for games and other applications, we’ve added support for the new video formats VP8 and WebM, as well as support for AAC and AMR-wideband encoding. The platform also provides new audio effects such as reverb, equalization, headphone virtualization, and bass boost.

New forms of communication: The platform now includes support for front-facing camera, SIP/VOIP, and Near Field Communications (NFC), to let developers include new capabilities in their applications.

For a complete overview of what’s new in the platform, see the Android 2.3 Platform Highlights.

Alongside the new platform, we are releasing updates to the SDK Tools (r8), NDK, and ADT Plugin for Eclipse (8.0.0). New features include:

Simplified debug builds: Developers can easily generate debug packages without having to manually configure the application’s manifest, making workflow more efficient.

Integrated ProGuard support: ProGuard is now packaged with the SDK Tools. Developers can now obfuscate their code as an integrated part of a release build.

HierarchyViewer improvements: The HierarchyViewer tool includes an updated UI and is now accessible directly from the ADT Plugin.

Preview of new UI Builder: An early release of a new visual layout editor lets developers create layouts in ADT by dragging and dropping UI elements from contextual menus. It’s a work in progress and we intend to iterate quickly on it.

To get started developing or testing applications on Android 2.3, visit the Android Developers site for information about the Android 2.3 platform, the SDK Tools, the ADT Plugin and the new NDK.

Check out the video below to learn more about the new developer features in Android 2.3.

The Android 2.2 SDK that was released at Google I/O contained a preview of the Froyo system image and today, we are releasing an update to bring it into sync with the system image pushed to Nexus One devices.

I encourage all developers to use the SDK manager to update to this version.

Performance & speed: The new Dalvik JIT compiler in Android 2.2 delivers between a 2-5X performance improvement in CPU-bound code vs. Android 2.1 according to various benchmarks.

New enterprise capabilities: We’ve added Exchange capabilities such as account auto-discovery and calendar sync. Device policy management APIs allow developers to write applications that can control security features of the device such as the remote wipe, minimum password, lockscreen timeout etc.

Faster, more powerful browser: We have brought the V8 JavaScript engine to the Android browser as part of 2.2. This has resulted in a 2-3X improvement in JavaScript performance vs. 2.1.

Rich set of new APIs and services: New data backup APIs enable apps to participate in data backup and restore, allowing an application's last data to be restored when installed on a new or a reset device. Apps can utilize Android Cloud to Device Messaging to enable mobile alert, send to phone, and two-way push sync functionality. Developers can now declare whether their app should be installed on internal memory or an SD card. They can also let the system automatically determine the install location. On the native side, a new API now gives access to Skia bitmaps.

Additions to Android Market: Android Market provides Android Application Error Reports, a new bug reporting feature, giving developers access to crash and freeze reports from users. Developers will be able to access these reports via their account on the Android Market publisher website.

For a complete list of everything we’ve included in Android 2.2, please see the platform highlights.

Developers can now download the Android 2.2 SDK and Android NDK, Revision 4 from the Android developer site.

Tools update

We are releasing new version of the Android SDK Tools, Revision 6, Eclipse plug-in ADT 0.9.7 and Android NDK, Revision 4.

Android SDK Tools, Revision 6, Eclipse plug-in 0.9.7

These new versions include support for library projects that will help you share code and resources across several Android projects.

Android NDK, Revision 4

Workflow improvements The new NDK brings a host of workflow improvement, from compilation, to debugging. Starting with 2.2, the NDK enables debugging native code on production devices.

ARMv7 instruction set support This release enables the generation of machine code for the ARMv7-A instruction set. Benefits include higher performance, as well as full use of the hardware FPU for devices that support it.

ARM Advanced SIMD (a.k.a. NEON) instruction support The NEON instruction set extension can be used to perform scalar computations on integers and floating points. However, it is an optional CPU feature and will not be supported by all Android ARMv7-A based devices. The NDK includes a tiny library named "cpufeatures" that can be used by native code to test at runtime the features supported by the device's target CPU.

For more information, please see the releases notes for the SDK Tools, ADT, and NDK.

As I said at the beginning, Android 2.2 will be here soon, and some devices will get the update in the coming weeks. I invite application developers to download the new SDK and tools and test your applications today.

Check out the video below to learn more about Android 2.2.

In addition to the new SDK, a new USB driver that supports Nexus One is also available today through the SDK Manager. The USB driver page contains more information.

Android 2.0 brings new developer APIs for sync, Bluetooth, and a few other areas. Using the new sync, account manager and contacts APIs, you can write applications to enable users to sync their devices to various contact sources. You can also give users a faster way to communicate with others by embedding Quick Contact within your application. With the new Bluetooth API, you can now easily add peer-to-peer connectivity or gaming to your applications. To get a more complete list of the new capabilities you can add to your applications, please go to the Android 2.0 highlights page.

Current developers can use the SDK Manager to add Android 2.0 support to their SDK as well as update their SDK Tools to revision 3. New developers can download the Android SDK from the download site. After the download, Android platforms must be added using the SDK Manager

The SDK Manager allows you to add new Android platforms to your SDK.

Android SDK Tools, revision 3 is required to develop for Android 2.0. It includes support for code coverage through the Ant build system, as well as Mac OS X 10.6 (Snow Leopard) support for the SDK and related tools. For those of you who develop using Eclipse, we are releasing ADT version 0.9.4 through the usual Eclipse update mechanism.

Over the next few months, we expect to see more and more Android devices being released. These devices will be running Android 1.5, 1.6, or 2.0. We are also planning a minor version update of Android 2.0 towards the end of the year, and that will be the last update for 2009. Below are some of the things you can do to be better prepared:

• Download the Android 2.0 platform and make sure your existing apps continue to work on new devices running Android 2.0.

• Make sure that your apps work when using the WVGA (800x480) & FWVGA (854x480) emulator skins. We expect devices with these types of screen, running Android 2.0 to be launched soon.

Checkout the video below for more information about Android 2.0.

The Android 1.6 SDK requires a new version of Android Development Tools (ADT). The SDK also includes a new tool that enables you to download updates and additional components, such as new add-ons or platforms.

You can expect to see devices running Android 1.6 as early as October. As with previous platform updates, applications written for older versions of Android will continue to run on devices with Android 1.6. Please test your existing apps on the Android 1.6 SDK to make sure they run as expected.

Over the next several weeks, we will publish a series of blog posts to help you get ready for the new developer technologies in Android 1.6. The following topics, and more, will be covered: how to adapt your applications to support different screen sizes, integrating with Quick Search Box, building gestures into your apps, and using the text-to-speech engine.

If you are interested to see some highlights of Android 1.6, check out the video below.

Happy coding!

For an overview of the new Android 1.5 features, see the 1.5 release notes page in our developer site.

I am also happy to let you know that our partners at HTC have made available new system images to upgrade your Android Dev Phone 1 (ADP1) to Android 1.5. This new version (which is only available for the ADP1) is based on the Cupcake branch from the Android Open Source Project and corresponds to the system image of the Android 1.5 SDK, release 1. If you have questions about the process of updating your device, you can ask the mailing list that we've set up.

I'd also like to note that Android developer phones like the ADP1 are intended for application development, rather than daily use. Additionally, they are operator-neutral and country-neutral, so they may not include certain features found on end-user devices.

We've also made changes to the developer tools and the structure of the SDK itself. Future Android SDK releases will include multiple versions of the Android platform. For example, this early-look includes Android platform versions 1.1 and 1.5. One benefit of this change is that developers can target different Android platform versions from within a single SDK installation. Another is that it enables developers to install Android SDK add-ons to access extended functionality that might be provided by OEMs, carriers, or other providers. We at Google are using this feature ourselves: this early-look SDK includes an add-on for the Google APIs. This add-on provides support for the Google Maps API, which was previously embedded in the "core" SDK.

To help you prepare your applications for the release of Android 1.5 on phones, over the next few weeks we'll be publishing a series of articles on this blog to highlight new APIs and other changes. In addition to the new APIs that I've mentioned, we'll cover topics such as OpenGL, asynchronous tasks, system settings, and new Activity callbacks.

I encourage you to start working with this early-look SDK, but please know that the APIs for Android 1.5 have not been finalized. The majority of the APIs are settled, but there may be some changes before the final release. As a result, it's very important that you don't release applications based on this early-look SDK, since they may not work on real devices. The applications you release should be built on the final Android 1.5 SDK release, which will be available around the end of this month.

I look forward to seeing all the great apps that use the new capabilities in Android 1.5. Happy coding!