Android的BroadcastReceiver的音量键上下 [英] Android BroadCastReceiver for volume key up and down

问题描述

如果用户presses音量键上下是有可能发现它在我的广播接收器？我需要完整的code。

If a user presses volume key up or down is it possible to detect it in my broadcast receiver? I need the full code.

下面是我的意图过滤器

IntentFilter filter = new IntentFilter();
filter.addAction("android.media.VOLUME_CHANGED_ACTION");

和我的的onReceive 方法

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");
         }
    }

这给了我一个空的KeyEvent ......任何想法？

It gives me a null KeyEvent... any idea?

推荐答案

没有一个EXTRA_KEY_EVENT额外的意图。它有一个额外的android.media.EXTRA_VOLUME_STREAM_VALUE其中包含新卷。

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.

int volume = (Integer)intent.getExtras().get("android.media.EXTRA_VOLUME_STREAM_VALUE");

如果您存储旧值，可以推断调高或调低音量是否pressed。

If you store the old value, you can infer whether volume up or down was pressed.

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