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Diffstat (limited to 'docs/html/sdk/android-2.0.jd')
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diff --git a/docs/html/sdk/android-2.0.jd b/docs/html/sdk/android-2.0.jd index 57283e5..9dadf8b 100644 --- a/docs/html/sdk/android-2.0.jd +++ b/docs/html/sdk/android-2.0.jd @@ -205,6 +205,7 @@ element in your application's manifest. </p> <p>For more information about how to use API Level, see the <a href="{@docRoot}guide/appendix/api-levels.html">API Levels</a> document. </p> + <h3 id="api-changes">API changes summary</h3> <h4>Bluetooth</h4> @@ -263,6 +264,62 @@ href="{@docRoot}guide/appendix/api-levels.html">API Levels</a> document. </p> <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> </ul> +<h4>Key events executed on key-up</h4> + +<p>Android 2.0 is designed to run on devices that use virtual keys for HOME, +MENU, BACK, and SEARCH, rather than physical keys. To support the best user +experience on those devices, the Android platform now executes these buttons at +key-up, for a key-down/key-up pair, rather than key-down. This helps prevent +accidental button events and lets the user press the button area and then drag +out of it without generating an event. </p> + +<p>This change in behavior should only affect your application if it is +intercepting button events and taking an action on key-down, rather than on +key-up. Especially if your application is intercepting the BACK key, you should +make sure that your application is handling the key events properly. </p> + +<p>In general, intercepting the BACK key in an application is not recommended, +however, if your application is doing so and it invokes some action on +key-down, rather than key-up, you should modify your code. </p> + +<p>If your application will use APIs introduced in Android 2.0 (API Level 5), +you can take advantage of new APIs for managing key-event pairs:</p> + +<ul> +<li>If you are intercepting the BACK key in an activity or dialog, just +implement the new {@link android.app.Activity#onBackPressed()} method. </li> +<li>If you are intercepting the BACK key in a view, you should track the key +event on key-down (through the new {@link android.view.KeyEvent#startTracking} +method), then invoke the action at key up. Here's a pattern you can use:</li> + +<pre> public boolean onKeyDown(int keyCode, KeyEvent event) { + if (keyCode == KeyEvent.KEYCODE_BACK + && event.getRepeatCount() == 0) { + event.startTracking(); + return true; + } + return super.onKeyDown(keyCode, event); + } + + public boolean onKeyUp(int keyCode, KeyEvent event) { + if (keyCode == KeyEvent.KEYCODE_BACK && event.isTracking() + && !event.isCanceled()) { + // *** DO ACTION HERE *** + return true; + } + return super.onKeyUp(keyCode, event); + }</pre> + +</ul> + +<p>If you want to update a legacy application so that its handling of the BACK +key works properly for both Android 2.0 and older platform versions, you +can use an approach similar to that shown above. Your code can catch the +target button event on key-down, set a flag to track the key event, and +then also catch the event on key-up, executing the desired action if the tracking +flag is set. You'll also want to watch for focus changes and clear the tracking +flag when gaining/losing focus.</p> + <h3 id="api-diff">API differences report</h3> <p>For a detailed view of API changes in Android {@sdkPlatformVersion} (API Level {@sdkPlatformApiLevel}), as compared to |