Android BroadCastReceiver 用于音量键上下
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Android BroadCastReceiver for volume key up and down
提问by malik M
If a user presses volume key up or down is it possible to detect it in my broadcast receiver? I need the full code.
如果用户向上或向下按音量键，是否可以在我的广播接收器中检测到它？我需要完整的代码。
Here is my Intent filter
这是我的意图过滤器
IntentFilter filter = new IntentFilter();
filter.addAction("android.media.VOLUME_CHANGED_ACTION");
and my onReceivemethod is
我的onReceive方法是
public void onReceive(Context arg0, Intent intent) {
KeyEvent ke = (KeyEvent)intent.getExtras().get(Intent.EXTRA_KEY_EVENT);
if (ke .getKeyCode() == KeyEvent.KEYCODE_VOLUME_UP) {
System.out.println("I got volume up event");
}else if (ke .getKeyCode() == KeyEvent.KEYCODE_VOLUME_DOWN) {
System.out.println("I got volume key down event");
}
}
It gives me a null KeyEvent... any idea?
它给了我一个空的 KeyEvent ......知道吗？
回答by Theus
The intent does not have an EXTRA_KEY_EVENT extra. It does have an extra android.media.EXTRA_VOLUME_STREAM_VALUE which contains the new volume.
该意图没有额外的 EXTRA_KEY_EVENT。它确实有一个额外的 android.media.EXTRA_VOLUME_STREAM_VALUE 包含新卷。
int volume = (Integer)intent.getExtras().get("android.media.EXTRA_VOLUME_STREAM_VALUE");
If you store the old value, you can infer whether volume up or down was pressed.
如果您存储旧值，您可以推断是否按下了增大或减小音量。
