<p>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: </p>
<ul>
<li>
QVGA (240x320, low density, small screen)
</li>
<li>
WQVGA (240x400, low density, normal screen)
</li>
<li>
FWQVGA (240x432, low density, normal screen)
</li>
<li>
HVGA (320x480, medium density, normal screen)
</li>
<li>
WVGA800 (480x800, high density, normal screen)
</li>
<li>
WVGA854 (480x854 high density, normal screen)
</li>
</ul>
<p>For more information about how to develop an application that displays and functions properly on all Android-powered devices, see <a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a>.</p>
<h2 id="dev-features">Developer Features</h2>
<p>The sections below provide information about new developer features offered by the downloadable Android 2.0 platform component.</p>
<li>Debug- and release-mode application signing. Release-mode signing includes integrated support for <code>zipalign</code> optimization. For more information, see <a href="{@docRoot}tools/publishing/app-signing.html#releasecompile">Signing Your Applications</a>.</li>
<li>Connect to a remote device using RFCOMM and send/receive data</li>
<li>Advertise RFCOMM services and listen for incoming RFCOMM connection</li>
</ul>
<h4>Sync adapters </h4>
<ul>
<li>New APIs for sync adapters to connect to any backend</li>
</ul>
<h4>Account Manager</h4>
<ul>
<li>Centralized account manager API to securely store and access auth tokens/passwords </li>
</ul>
<h4>Contacts</h4>
<ul>
<li>New contacts APIs that allow for data from multiple accounts</li>
<li>New Quick Contact framework APIs enable developers to create contact badges in their app. Clicking on the badge opens a window with a list of ways to contact the person with one click.</li>
<li>New parameters for color effect, scene mode, flash mode, focus mode, white balance, rotation, and other settings.</li>
<li>New ZoomCallback interface to perform actions when the zoom level has changed.</li>
</ul>
<h4>Media</h4>
<ul>
<li>MediaScanner now generates thumbnails for all images when they are inserted into MediaStore.</li>
<li>New Thumbnail API for retrieving image and video thumbnails on demand.</li>
</ul>
<h4>Other Framework</h4>
<ul>
<li>New system themes in android.R.style to easily display activities on top of the current system wallpaper or keep the previous activity visible in the background. </li>
<li>New WallpaperManager API replaces and extends the wallpaper APIs that were previously in Context, to allow applications to request and set the system wallpaper.</li>
<li>New Service APIs to help applications correctly handle Service life-cycle, in particular low memory situations where a Service may be killed while it is running.
<ul>
<li>Service.setForeground() has been deprecated and now effectively performs no operation. This is replaced with a new API, startForeground(), that helps (and requires) associating an ongoing notification with the foreground state.</li>
</ul>
</li>
<li>MotionEvent can now report simultaneous-touch information for devices that support it. Up to three pointers can be tracked simultaneously. </li>
<li>KeyEvent has new key dispatching APIs, to help implement action-on-up and long press behavior, as well a new mechanism to cancel key presses (for virtual keys).</li>
<li>WindowManager.LayoutParams has new constants that allow a window to wake up the screen when it is displayed and show the window even if the screen is locked. This allows applications to more cleanly implement things like alarm clocks that should wake the device.</li>
<li>New Intent APIs that broadcast the docking state of the device and allow applications to launch special activities when the device is placed in a desktop or car dock.</li>
