那么这引出一个问题，如何在 Camera/VideoCamera Activity中监听耳机键。
耳机键在 android 中的定义为
/** Key code constant: Headset Hook key.
* Used to hang up calls and stop media. */
public static final int KEYCODE_HEADSETHOOK = 79;
主要用来接听/挂断 电话，播放/暂停音乐视频等
监听耳机键有两种方式：
1，直接在 Activity 的 onKeyDown 或 onKeyUp 函数中添加对应的 case 即可
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
switch (keyCode) {
……
case KeyEvent.KEYCODE_HEADSETHOOK:
//add your code here
……
}
return super.onKeyUp(keyCode, event);
}
2，注册 BroadcastReceiver 来响应该按键
// listener media button
private BroadcastReceiver mMediaButtonReceiver = null;
private class MediaButtonBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.v(TAG," call MediaButtonBroadcastReceiver");
KeyEvent event = (KeyEvent) intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
Log.v(TAG, " event "+event);
if ((event != null)&& (event.getKeyCode() == KeyEvent.KEYCODE_HEADSETHOOK)) {
Toast.makeText(VideoCamera.this, R.string.hook, Toast.LENGTH_SHORT).show();
}
}
}
//registerReceiver
IntentFilter mediaButtonIntentFilter = new IntentFilter();
mediaButtonIntentFilter.addAction(Intent.ACTION_MEDIA_BUTTON);
mMediaButtonReceiver = new MediaButtonBroadcastReceiver();
registerReceiver(mMediaButtonReceiver, mediaButtonIntentFilter);
//unregisterReceiver
if (mMediaButtonReceiver != null){
unregisterReceiver(mMediaButtonReceiver);
mMediaButtonReceiver = null;
}