android - Xamarin.Android:如何隐藏音频？

Question

我正在开发Xamarin.Forms应用，在iOS中，我可以通过以下代码来隐藏音频:

AVAudioSession.SharedInstance().SetCategory(AVAudioSessionCategory.Playback, AVAudioSessionCategoryOptions.DuckOthers);

Android相当于什么？

提前致谢。

Answer 1

我解决了在Droid项目上创建此类的问题:

class NotificationManager
{
    static public Android.Media.AudioManager audioManager = null;
    static Activity mainActivity = null;

    public static Activity MainActivity
    {
        set { mainActivity = value; }
    }

    Android.Media.AudioManager.IOnAudioFocusChangeListener listener = null;

    private class FocusChangeListener : Java.Lang.Object, Android.Media.AudioManager.IOnAudioFocusChangeListener
    {
        public void OnAudioFocusChange(AudioFocus focusChange)
        {
            switch (focusChange)
            {
                // We will take any flavor of AudioFocusgain that the system gives us and use it.
                case AudioFocus.GainTransient:
                case AudioFocus.GainTransientMayDuck:
                    break;
                case AudioFocus.Gain:
                    break;
                // If we get any notificationthat removes focus - just terminate what we were doing.
                case AudioFocus.LossTransientCanDuck:
                    break;
                case AudioFocus.LossTransient:
                case AudioFocus.Loss:
                    break;
                default:
                    break;
            }
        }
    }

    public Boolean RequestAudioResources()
    {
        listener = new FocusChangeListener();

        var ret = audioManager.RequestAudioFocus(listener, Stream.Music, AudioFocus.GainTransientMayDuck);
        if (ret == AudioFocusRequest.Granted)
        {
            return (true);
        }
        else if (ret == AudioFocusRequest.Failed)
        {
            return (false);
        }
        return (false);
    }

    public void ReleaseAudioResources()
    {
        if (listener != null)
            audioManager.AbandonAudioFocus(listener);
    }
}

然后在MainActivity中设置:

NotificationManager.audioManager = (Android.Media.AudioManager)GetSystemService(Context.AudioService);
NotificationManager.MainActivity = this;

此时，我可以通过调用RequestAudioResources()和ReleaseAudioResources()方法来管理音频。

更改音频焦点后，将调用OnAudioFocusChange()方法，您可以执行更多操作。