Question

我正在开发一个应用程序，它需要按下音量键和向上事件来做某事。当屏幕很亮时，我可以覆盖onKeyDown和oneKeyUp方法。但如果手机被锁定，这种方法是不可行的出。我想知道手机锁定后如何实现它？

Answer 1

您可以使用SettingsObserver将卷更改作为备份解决方案进行捕获：

SettingsObserver audioObserver = new SettingsObserver(context, new Handler());

对于设置观察者：

public class SettingsObserver extends ContentObserver {

    /**
     * Application context
     */
    private Context context = null;


    /**
     * build SettingsObserver
     *
     * @param context retrieve application context to look for Audio Manager service
     * @param handler The handler to run {@link #onChange} on, or null if none.
     */
    public SettingsObserver(Context context, Handler handler, DroidEvent manager) {
        super(handler);

        this.context = context;
    }

    @Override
    public boolean deliverSelfNotifications() {
        return super.deliverSelfNotifications();
    }

    @Override
    public void onChange(boolean selfChange) {
        super.onChange(selfChange);

        AudioManager audio = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);

        if (audio != null) {
            byte newVolumeMedia = (byte) audio.getStreamVolume(AudioManager.STREAM_MUSIC);
            byte newVolumeSystem = (byte) audio.getStreamVolume(AudioManager.STREAM_SYSTEM);
            byte newVolumeRing = (byte) audio.getStreamVolume(AudioManager.STREAM_RING);
            byte newVolumeNotification = (byte) audio.getStreamVolume(AudioManager.STREAM_NOTIFICATION);
            byte newVolumeDtmf = (byte) audio.getStreamVolume(AudioManager.STREAM_DTMF);
            byte newVolumeVoiceCall = (byte) audio.getStreamVolume(AudioManager.STREAM_VOICE_CALL);
        }
    }
}

注册您的ContentObserver：

context.getContentResolver().registerContentObserver(android.provider.Settings.System.CONTENT_URI, true, audioObserver);

这样您就可以检索所有类型的音量事件，这会让您知道音量键已被按下或按下

手机锁定后，听取Android音量键向下和向上事件

1 个答案: