Android 2.1 Platform

API Level: 7

Android 2.1 is a minor platform release deployable to Android-powered handsets starting in January 2010. This release includes new API changes and bug fixes. For information on changes, see the Framework API section.

For developers, the Android 2.1 platform is available as a downloadable component for the Android SDK. The downloadable platform includes a fully compliant Android library and system image, as well as a set of emulator skins, sample applications, and more. The downloadable platform includes no external libraries.

To get started developing or testing against the Android 2.1 platform, use the Android SDK and AVD Manager tool to download the platform into your SDK. For more information, see Adding SDK Components.

Platform Highlights

Android 2.1 does not add significant user features, see the Android 2.0 Platform Highlights document for the latest user features.

Revisions

The sections below provide notes about successive releases of the Android 2.1 platform component for the Android SDK, as denoted by revision number. To determine what revision(s) of the Android 2.1 platforms are installed in your SDK environment, refer to the "Installed Packages" listing in the Android SDK and AVD Manager.

Android 2.1, Revision 2 (May 2010)

Dependencies:

Requires SDK Tools r6 or higher.

Tools:

• Adds support for library projects in the Ant build system.
• Adds improved layout rendering in ADT’s visual layout editor.

Android 2.1, Revision 1 (January 2010)

Dependencies:

Requires SDK Tools r4 or higher.

API Level

The Android 2.1 platform delivers an updated version of the framework API. The Android 2.1 API is assigned an integer identifier — 7 — 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 2.1 in your application, you need to set the proper value, "7", 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 document.

Framework API Changes

The sections below provide information about changes made to the application framework API provided by the Android 2.1 platform.

Live Wallpapers

The following additions provide APIs for you to develop animated wallpapers:

• New android.service.wallpaper package.
• New WallpaperInfo class.
• Updated WallpaperManager.

Additionally, if your application uses or provides Live Wallpapers, you must remember to add a <uses-feature> element to the application's manifest, declaring the attribute android:name="android.software.live_wallpaper". For example:

<uses-feature android:name="android.software.live_wallpaper" />

When you've published your application, Android Market checks for the presence of this element and uses it as a filter, ensuring that your application is not made available to users whose devices do not support Live Wallpapers.

Telephony

• New SignalStrength class provides information about the device's current network signal. This can be acquired from the new onSignalStrengthsChanged(SignalStrength) callback.
• New onDataConnectionStateChanged(int, int) callback.

Views

• New View methods isOpaque() and onDrawScrollBars(Canvas).
• New RemoteViews methods addView(int, RemoteViews) and removeAllViews(int).
• New ViewGroup methods isChildrenDrawingOrderEnabled() and setChildrenDrawingOrderEnabled(boolean).

WebKit

• New WebStorage methods to manipulate web storage databases.
• New GeolocationPermissions methods to get Geolocation permissions from, and set them on the WebView.
• New WebSettings methods to manage settings for app cache, web storage, and zooming based on screen density.
• New WebChromeClient methods for handling video, browsing history, custom Views, app cache limits, and more.

API differences report

For a detailed view of all API changes in Android 2.1 (API Level 7), as compared to API Level 6, see the API Differences Report.

Built-in Applications

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

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 2.1 system image are listed below (with language_country/region locale descriptor).

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)
• WQVGA (240x400, low density, normal screen)
• FWQVGA (240x432, low density, normal 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.