我们在Windows下常常有一些快捷键来启动某个应用的需求,同样在我们的Android系统下也可以实现这样的作用。
比如按下CAMERA键,来启动Camera应用。
使用步骤如下,
1 先定义好CAMEAR键值,比如KEYCODE_CAMERA=27并要在xxx_Keypad.kl定义好扫描码与CAMERA对应的关系
如 key 212 CAMERA
2 定义相关BROADCAST_INTENT_ACTION @Intent.java
@SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
public static final String ACTION_CAMERA_BUTTON = "android.intent.action.CAMERA_BUTTON";
3 在系统文件PhoneWindow.java中有onKeyDown()函数来捕获CAMERA键值并发送相关intent.
case KeyEvent.KEYCODE_CAMERA: {
....
// Broadcast an intent that the Camera button was longpressed
Intent intent = new Intent(Intent.ACTION_CAMERA_BUTTON, null);
intent.putExtra(Intent.EXTRA_KEY_EVENT, event);
getContext().sendOrderedBroadcast(intent, null);
}
4 在camera应用下如果要接收这个Broadcast消息,需要在AndroidManifest.xml中增加receive 相关的intent-filter.
<receiver android:name="CameraButtonIntentReceiver">
<intent-filter>
<action android:name="android.intent.action.CAMERA_BUTTON" />
</intent-filter>
</receiver>
5 定义类CameraButtonIntentReceiver 并重载onReceive方法来启动CameraActivity
public class CameraButtonIntentReceiver extends BroadcastReceiver {
public CameraButtonIntentReceiver() {
}
@Override
public void onReceive(Context context, Intent intent) {
// Try to get the camera hardware
CameraHolder holder = CameraHolder.instance();
if (holder.tryOpen() == null) return;
// We are going to launch the camera, so hold the camera for later use
holder.keep();
holder.release();
Intent i = new Intent(Intent.ACTION_MAIN);
i.setClass(context, Camera.class);
i.addCategory("android.intent.category.LAUNCHER");
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
}
}