onKeyDown在服务中？(全球热键)

Question

我基本上试图实现的是自定义全局热键,换句话说,"当我按下某些按钮时会发生某些事情,无论哪个程序当前位于顶部".
我认为需要一项服务.

我有一个快速而肮脏的测试,只是告诉我如果它是活动窗口,那么按下了什么.

public boolean onKeyDown(int keyCode, KeyEvent event) {
    char pop;
    pop = (char)event.getUnicodeChar();
    Toast.makeText(this, Character.toString(pop) , Toast.LENGTH_SHORT).show();
    return super.onKeyDown(keyCode, event);
  }

但显然如果我改变窗口或进入文本框它不起作用.如果我将它直接粘贴到服务(或imputmethodservice)并启动所述服务没有任何反应.(可能需要一些权限吗？)我出错的任何建议？或者更好的方法来捕捉按下哪个按钮？

谢谢!

Answer 1

你不能做这个 :)

Answer 2

这需要 Lollipop (v5.0/API 21) 或更高版本

我的目标是从服务调整系统音量，所以这只会听摇杆。不过，媒体可以采取任何行动。

它将覆盖音量键操作，因此可能不需要全局使用它。

public class VolumeKeyController {

    private MediaSessionCompat mMediaSession;
    private final Context mContext;

    public VolumeKeyController(Context context) {
        mContext = context;
    }

    private void createMediaSession() {
        mMediaSession = new MediaSessionCompat(mContext, KeyUtil.log);

        mMediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS |
                MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
        mMediaSession.setPlaybackState(new Builder()
                .setState(PlaybackStateCompat.STATE_PLAYING, 0, 0)
                .build());
        mMediaSession.setPlaybackToRemote(getVolumeProvider());
        mMediaSession.setActive(true);
    }

    private VolumeProviderCompat getVolumeProvider() {
        final AudioManager audio = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);

        int STREAM_TYPE = AudioManager.STREAM_MUSIC;
        int currentVolume = audio.getStreamVolume(STREAM_TYPE);
        int maxVolume = audio.getStreamMaxVolume(STREAM_TYPE);

        return new VolumeProviderCompat(VolumeProviderCompat.VOLUME_CONTROL_RELATIVE, maxVolume, currentVolume) {
            @Override
            public void onAdjustVolume(int direction) {
                // Volume Up = AudioManager.ADJUST_LOWER, Volume Down = AudioManager.ADJUST_LOWER, Release = AudioManager.ADJUST_SAME
                // Replace with your action, if you don't want to adjust system volume
                if (direction == AudioManager.ADJUST_RAISE) {
                    audio.adjustStreamVolume(STREAM_TYPE,
                            AudioManager.ADJUST_RAISE, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
                }
                else if (direction == AudioManager.ADJUST_LOWER) {
                    audio.adjustStreamVolume(STREAM_TYPE,
                            AudioManager.ADJUST_LOWER, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
                }
                setCurrentVolume(audio.getStreamVolume(STREAM_TYPE));
            }
        };
    }

    // Call when control needed, add a call to constructor if needed immediately
    public void setActive(boolean active) {
        if (mMediaSession != null) {
            mMediaSession.setActive(active);
            return;
        }
        createMediaSession();
    }

    // Call from Service's onDestroy method
    public void destroy() {
        if (mMediaSession != null) {
            mMediaSession.release();
        }
    }
}