*API Level:* **4**

Android 1.6 is a minor platform release
deployable to Android-powered handsets since October 2009.
The platform includes new features for users and developers, as well as changes
in the Android framework API.

For developers, a new release of the Android 1.6 platform
is available as a downloadable component for the Android SDK. The platform
--- Android 1.6 r2 --- includes a fully compliant Android library and
system image, as well as a set of emulator skins, sample applications, and minor
development updates. The downloadable platform is fully compliant (API Level 4)
and includes no external libraries.

To get started developing or testing against the Android
1.6 platform, use the Android SDK and AVD Manager tool to
download the latest Android 1.6 platform into your Android 1.6 or later SDK.

## Platform Highlights

For a list of new user features and platform highlights, see the [Android
1.6 Platform Highlights](https://developer.android.com/about/versions/android-1.6-highlights.html) document.

## API Level

The Android 1.6 platform delivers an updated version of
the framework API. The Android 1.6 API
is assigned an integer identifier ---
**4** --- that is
stored in the system itself. This identifier, called the "API Level", allows the
system to correctly determine whether an application is compatible with
the system, prior to installing the application.

To use APIs introduced in Android 1.6 in your
application, you need to set the proper value, "4", in the
`android:minSdkVersion` attributes of the `<uses-sdk>`
element in your application's manifest.

For more information about how to use API Level, see the [API Levels](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) document.

## Framework API Changes

The sections below provide information about the application framework API provided by the Android 1.6 platform.

### UI framework

- New classes in [android.view.animation](https://developer.android.com/reference/android/view/animation/package-summary) to control the behavior of animations:
  - `AnticipateInterpolator`
  - `AnticipateOvershootInterpolator`
  - `BounceInterpolator`
  - `OvershootInterpolator`
- New XML attribute `android:onClick` to specify a View's [View.OnClickListener](https://developer.android.com/reference/android/view/View.OnClickListener) from a layout file.
- New support for dealing with varying screen densities. Density information is associated with Bitmap and Canvas for performing the correct scaling. The framework will automatically scale bitmaps and nine-patches based on the density the resource was found under and the density of the screen, etc.
- To use APIs introduced in Android 1.6 in your application, you need to set the proper value, "4", in the attributes of the `<uses-sdk>` element in your application's manifest.

### Search framework

- Applications can now expose relevant content to users as search suggestions in the Quick Search Box, a new device-wide search capability that is accessible from the home screen. To support this, the search framework adds new attributes to the searchable metadata file. For complete information, see the [SearchManager](https://developer.android.com/reference/android/app/SearchManager) documentation.

### Accessibility framework

- New [android.accessibility](https://developer.android.com/reference/android/view/accessibility/package-summary) package that includes classes for capturing accessibility events and forwarding them to an [AccessibilityService](https://developer.android.com/reference/android/accessibilityservice/package-summary) handler.
- New [AccessibilityService](https://developer.android.com/reference/android/accessibilityservice/package-summary) package that lets your application track user events and provide visual, audible, or haptic feedback to the user.

### Gesture input

- New [gesture](https://developer.android.com/reference/android/gesture/package-summary) API for creating, recognizing, loading, and saving gestures.

### Text-to-speech

- New [android.speech.tts](https://developer.android.com/reference/android/speech/tts/package-summary) package provides classes for synthesizing speech from text, for immediate playback or to create a sound file.

### Graphics

- Classes in [android.graphics](https://developer.android.com/reference/android/graphics/package-summary) now support scaling for different screen densities.

### Telephony

- New [SmsManager](https://developer.android.com/reference/android/telephony/SmsManager) and other classes for sending and receiving SMS messages.

### Utilities

- New [DisplayMetrics](https://developer.android.com/reference/android/util/DisplayMetrics) fields for determining the density of the current device screen.

### Android Manifest elements

- New [`<supports-screens>`](https://developer.android.com/guide/topics/manifest/supports-screens-element) element lets you specify the device screen sizes that your application is designed and tested to support, where "size" is a combination of resolution and density. If your application is run on a device whose screen size is not specified in the `<supports-screen>` element, the system displays the application in *compatibility mode* , which performs best-effort scaling of the application UI to match the resolution and density of the screen.

  The attributes available for defining an application's screen support are:

  - `smallScreen`: Boolean value that indicates whether the application is designed to run on devices with small screens. Examples: QVGA low density; VGA high density.
  - `normalScreens`: Boolean value that indicates whether the application is designed to run on devices with normal screens. Examples: WQVGA low density; HVGA medium density; WVGA high density.
  - `largeScreens`: Boolean value that indicates whether the application is designed to run on devices with significantly larger screens, such that special care may be required on the application's part to make proper use of the screen area. Examples: VGA medium density; WVGA medium density.
  - `anyDensity`: Boolean value that indicates whether the application can accommodate any screen density.
  - `resizable`: Boolean value that indicates whether the application can expand its layout to fit slightly larger screens.

  <br />

- New [`<uses-feature>`](https://developer.android.com/guide/topics/manifest/uses-feature-element) element lets an application specify hardware (or other) features that it requires to function normally. When an application specifies such features, the system allows the application to be installed only on devices that offer the required features. The element supports these attributes:
  - `name`: The name of the feature required by the application. Currently accepts "android.hardware.camera" and "android.hardware.camera.autofocus" values, which specify that a camera and camera autofocus are required, respectively.
  - `glEsVersion`: Indicates the minimum version of OpenGL ES required.
- New attributes for the [`<uses-sdk>`](https://developer.android.com/guide/topics/manifest/uses-sdk-element) element:
  - `targetSdkVersion`: Indicates the API Level that the application is targeting. It is able to run on older versions (down to minSdkVersion), but was explicitly tested to work with the version specified here. Specifying this version allows the platform to disable compatibility code that is not required or enable newer features that are not available to older applications.
  - `maxSdkVersion`: Indicates the maximum API Level on which an application is designed to run. **Important:** Please read the [`<uses-sdk>`](https://developer.android.com/guide/topics/manifest/uses-sdk-element) documentation before using this attribute.

### New permissions

- [CHANGE_WIFI_MULTICAST_STATE](https://developer.android.com/reference/android/Manifest.permission#CHANGE_WIFI_MULTICAST_STATE): Allows applications to enter Wi-Fi Multicast mode.
- [GLOBAL_SEARCH](https://developer.android.com/reference/android/Manifest.permission#GLOBAL_SEARCH): Allows the global search system to access the data of a specified content provider.
- [INSTALL_LOCATION_PROVIDER](https://developer.android.com/reference/android/Manifest.permission#INSTALL_LOCATION_PROVIDER): Allows an application to install a location provider into the Location Manager.
- READ_HISTORY_BOOKMARKS: Allows an application to read (but not write) the user's browsing history and bookmarks.
- WRITE_HISTORY_BOOKMARKS: Allows an application to write (but not read) the user's browsing history and bookmarks.
- [WRITE_EXTERNAL_STORAGE](https://developer.android.com/reference/android/Manifest.permission#WRITE_EXTERNAL_STORAGE): Allows an application to write to external storage. Applications using API Level 3 and lower will be implicitly granted this permission (and this will be visible to the user); Applications using API Level 4 or higher must explicitly request this permission.

### API differences report

For a detailed view of API changes in Android 1.6 (API Level 4), as compared to
the previous version, see the [API
Differences Report](https://developer.android.com/sdk/api_diff/4/changes).

## Built-in Applications

The system image included in the downloadable platform provides these
built-in applications:

|---|---|
| - Alarm Clock - Browser - Calculator - Camcorder - Camera - Contacts - Custom Locale (developer app) - Dev Tools (developer app) - Dialer | - Email - Gallery - Gestures Builder - IME for Japanese text input - Messaging - Music - Settings - Spare Parts (developer app) |

## Locales

The system image included in the downloadable platform provides a variety of
built-in locales. In some cases, region-specific strings are available for the
locales. In other cases, a default version of the language is used. The
languages that are available in the Android 1.6 system
image are listed below (with *language* _*country/region*
locale descriptor).

|---|---|
| - Chinese, PRC (zh_CN) - Chinese, Taiwan (zh_TW) - Czech (cs_CZ) - Dutch, Netherlands (nl_NL) - Dutch, Belgium (nl_BE) - English, US (en_US) - English, Britain (en_GB) - English, Canada (en_CA) - English, Australia (en_AU) - English, New Zealand (en_NZ) - English, Singapore(en_SG) - French, France (fr_FR) - French, Belgium (fr_BE) | - French, Canada (fr_CA) - French, Switzerland (fr_CH) - German, Germany (de_DE) - German, Austria (de_AT) - German, Switzerland (de_CH) - German, Liechtenstein (de_LI) - Italian, Italy (it_IT) - Italian, Switzerland (it_CH) - Japanese (ja_JP) - Korean (ko_KR) - Polish (pl_PL) - Russian (ru_RU) - Spanish (es_ES) |

Localized UI strings match the locales that are accessible
through Settings.

## Emulator Skins

The downloadable platform includes a set of emulator skins that you can
use for modeling your application in different screen sizes and resolutions.
The emulator skins are:

- QVGA (240x320, low density, small screen)
- HVGA (320x480, medium density, normal screen)
- WVGA800 (480x800, high density, normal screen)
- WVGA854 (480x854 high density, normal screen)

For more information about how to develop an application that displays and functions properly on all Android-powered devices, see [Supporting Multiple Screens](https://developer.android.com/guide/practices/screens_support).