在 Android 上监听音量变化事件

问题描述

有没有什么方法可以在 Android 上监听音量变化的事件，而不只是接管音量按钮?

Is there any way to listen to the event of volume change on Android, without just taking over the volume buttons?

我发现唯一有效的是 这里，但只有在音量控制消失后才能使用.

The only thing I've found that works is here, but it works only after the volume control has disappeared.

并非所有设备都有音量按钮，我需要在音量变化发生时立即捕捉它们，而不是在音量对话框消失后捕捉.

Not all devices have volume buttons, and I need to capture the volume changes as soon as they occur, and not after the volume dialog is gone.

推荐答案

更好，可以注册一个ContentObserver，如下:

Better, you can register a ContentObserver as follows:

  getApplicationContext().getContentResolver().registerContentObserver(android.provider.Settings.System.CONTENT_URI, true, new ContentObserver(){...} );

您的 ContentObserver 可能如下所示:

Your ContentObserver might look like this:

public class SettingsContentObserver extends ContentObserver {
    private AudioManager audioManager;

    public SettingsContentObserver(Context context, Handler handler) {
        super(handler);
        audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
    }

    @Override
    public boolean deliverSelfNotifications() {
        return false;
    }

    @Override
    public void onChange(boolean selfChange) {
        int currentVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);

        Log.d(TAG, "Volume now " + currentVolume);
    }
}

完成后:

getApplicationContext().getContentResolver().unregisterContentObserver(mContentObserver);

但请注意 - 如果快速按下大量按钮，有时通知似乎会延迟.

One caution, though - sometimes the notifications seem to be delayed if there are lots of button presses quickly.

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