Question

我正在使用Xamarin在Android中工作。我有一个广播接收器，它可以像这样抓住耳机上的按钮：

 public class MyMediaButtonBroadcastReceiver : BroadcastReceiver
    {
        public string ComponentName { get { return Class.Name; } }

        private MediaMetadataRetriever reader = new MediaMetadataRetriever();

        public override void OnReceive(Context context, Intent intent)
        {
            if (intent.Action != Intent.ActionMediaButton)
                return;

            var keyEvent = (KeyEvent)intent.GetParcelableExtra(Intent.ExtraKeyEvent);

            switch (keyEvent.KeyCode)
            {
                case Keycode.Headsethook:
                    break;
                case Keycode.MediaPlay:
                    Toast.MakeText(Activity_Player.ctx, "PLAY", ToastLength.Short).Show();
                    break;
                case Keycode.MediaPlayPause:

                    break;
                case Keycode.MediaNext:
                    Toast.MakeText(Activity_Player.ctx, "NEXT", ToastLength.Short).Show();

                    break;
                case Keycode.MediaPrevious:
                    Toast.MakeText(Activity_Player.ctx, "Prev", ToastLength.Short).Show();

                    break;
            }
        }

现在，一旦解开了耳机挂钩，我需要向我的mainactivity发送另一个本地广播。

这意味着，我的主要活动中需要一个监听器函数，该函数现在可以在主要活动中触发函数。但是我还没有找到关于如何接收本地广播的任何信息，而只是找到了如何发送它的信息。你们能帮我吗？谢谢:)

编辑：

[BroadcastReceiver]
[IntentFilter(new[] { Intent.ActionMediaButton })]
public class MyMediaButtonBroadcastReceiver : BroadcastReceiver
{
    public string ComponentName { get { return Class.Name; } }

    public override void OnReceive(Context context, Intent intent)
    {
        if (intent.Action != Intent.ActionMediaButton)
            return;

        var keyEvent = (KeyEvent)intent.GetParcelableExtra(Intent.ExtraKeyEvent);

        switch (keyEvent.KeyCode)
        {
            case Keycode.Headsethook:
                Activity_Player.Instance.PlayOrPauseLogic();
                break;
            case Keycode.MediaPlay:
                Toast.MakeText(Activity_Player.ctx, "PLAY", ToastLength.Short).Show();
                Activity_Player.Instance.PlayOrPauseLogic();
                break;
            case Keycode.MediaPlayPause:
                Activity_Player.Instance.PlayOrPauseLogic();
                break;
            case Keycode.MediaNext:
                Toast.MakeText(Activity_Player.ctx, "NEXT", ToastLength.Short).Show();
                if(Activity_Player.CurrentSongObject != null)
                    Activity_Player.Instance.ChooseRandomNewSongAndPlay(false);
                break;
            case Keycode.MediaPrevious:
                Toast.MakeText(Activity_Player.ctx, "Prev", ToastLength.Short).Show();
                if (Activity_Player.CurrentSongObject != null)
                    Activity_Player.mediaPlayer.SeekTo(0);
                break;
        }
    }

}

Answer 1

如何从本地广播管理器接收广播消息？

让我们假设您有一个名为{BetcastReceiver}的服务BroadcastReceiver，它会根据Intent附加内容进行操作。在此示例中，如果我收到额外的“播放”意图，我将使用该信息来做些事情。

将其作为活动的内部类：

[BroadcastReceiver]
public class ServiceBroadcastReceiver : BroadcastReceiver
{
    Context context;

    public ServiceBroadcastReceiver(Context context)
    {
       this.context = context;
    }
    public override void OnReceive(Context context, Intent intent)
    {
        if (intent.HasExtra("play"))
        {
           // sent a "play" cmd, do something.
           // context is your activity, you can call methods on it
           (context as SomeActivity)?.PlayReceived();
        }
    }
}

现在要向该接收方发送广播：

var intent = new Intent(Application.Context, typeof(ServiceBroadcastReceiver));
intent.PutExtra("play", true);
SendBroadcast(intent);

运行“活动”时，您可以注册以接收以下广播：

在OnResume覆盖中，您可以创建/注册它：

 // serviceBroadcastReceiver is a class level variable 
 serviceBroadcastReceiver = new ServiceBroadcastReceiver(this);
 RegisterReceiver(packageBroadcastReceiver, intentFilter);

在您的OnPause覆盖中，取消注册并清理：

UnregisterReceiver(serviceBroadcastReceiver);
serviceBroadcastReceiver.Dispose();
serviceBroadcastReceiver = null;

如何从本地广播管理器接收广播消息？

1 个答案: