Xamarin 通知 Android 崩溃 [英] Xamarin Notification Android Crash

问题描述

我收到以下异常:

Java.Lang.IllegalStateException:指定的孩子已经有一个父母.您必须在孩子的父母拳头上调用 removeVeiw().

Java.Lang.IllegalStateException: The specified child already has a parent. You must call removeVeiw() on the child's parent fist.

运行以下代码块时.这一切都从我的表单页面开始，按下按钮使用警报管理器生成预定的通知.问题是如果点击通知，如果应用程序仍然处于活动状态，则会抛出上述异常.

when running the following code blocks. It all starts in my Forms Page with a button press that uses the alarm manager to generate a scheduled notification. The problem is that if the notification is clicked on, the above exception gets thrown if the app is still active.

如果我在手机上切换应用程序，然后单击通知，它会按预期恢复应用程序而不会崩溃.

If I switch applications on the phone, then click the notification, it brings the application back up as intended without the crash.

以下是此工作流程的相关代码片段:

Below are the code snippets in question for this workflow:

来自 xamarin 页面:

from xamarin page:

 private void BtnStartJob_Clicked(object sender, EventArgs e)
    {
        lblStatus.Text = "";
        if (btnStartJob.Text == "Start Job")
        {
            tmrToggle.StartCommand.Execute(null);
            App.Manager.StartJob(App.Manager.currentTimesheet.ProjectID);
            btnStartJob.Text = "Start Break";
        }
        else if (btnStartJob.Text == "End Break")
        {
            tmrAlert.PauseCommand.Execute(null);
            tmrToggle.StartCommand.Execute(null);
            App.Manager.EndBreak(App.Manager.currentTimesheet.TimesheetID);
            btnStartJob.Text = "Start Break";
            var notificationService = DependencyService.Get<INotificationService>();
            notificationService.CancelNotification();
        }
        else if (btnStartJob.Text == "Start Break")
        {
            tmrAlert.StartCommand.Execute(null);
            tmrToggle.PauseCommand.Execute(null);
            App.Manager.StartBreak(App.Manager.currentTimesheet.TimesheetID);
            btnStartJob.Text = "End Break";

            // schedule the notification here.
            var notificationService = DependencyService.Get<INotificationService>();
            notificationService.CreateNotification("Take Action", "Your break started 1 second ago, please take action.", TimeSpan.FromSeconds(15).Ticks);
        }
    }

通知服务

    public class NotificationService : INotificationService
{

    public void CancelNotification()
    {
        var alarmIntent = new Intent(Android.App.Application.Context, typeof(AlarmReceiver));            
        var pending = PendingIntent.GetBroadcast(Android.App.Application.Context, 0, alarmIntent, PendingIntentFlags.UpdateCurrent);

        var alarmManager = Android.App.Application.Context.GetSystemService("alarm").JavaCast<AlarmManager>();
        alarmManager.Cancel(pending);            
    }

    public void CreateNotification(string title, string message, long durationInTicks)
    {
        var duration = TimeSpan.FromTicks(durationInTicks);

        var alarmIntent = new Intent(Forms.Context, typeof(AlarmReceiver));
        alarmIntent.PutExtra("title", title);
        alarmIntent.PutExtra("message", message);

        var pending = PendingIntent.GetBroadcast(Android.App.Application.Context, 0, alarmIntent, PendingIntentFlags.UpdateCurrent);

        var alarmManager = Android.App.Application.Context.GetSystemService("alarm").JavaCast<AlarmManager>();
        alarmManager.Set(AlarmType.ElapsedRealtime, duration.Milliseconds, pending);
    }
}    

警报接收器:

    [BroadcastReceiver]
class AlarmReceiver : BroadcastReceiver
{
    public override void OnReceive(Context context, Intent intent)
    {
        var message = intent.GetStringExtra("message");
        var title = intent.GetStringExtra("title");

        var resultIntent = new Intent(context, typeof(MainActivity));
        resultIntent.SetFlags(ActivityFlags.NewTask | ActivityFlags.ClearTask);

        var pending = PendingIntent.GetActivity(context, 0,
            resultIntent,
            PendingIntentFlags.CancelCurrent);

        var builder =
            new Notification.Builder(context)
                .SetContentTitle(title)
                .SetContentText(message)                    
                .SetSmallIcon(Resource.Drawable.WESSUClogo)
                .SetDefaults(NotificationDefaults.All);

        builder.SetContentIntent(pending);

        var notification = builder.Build();

        var manager = NotificationManager.FromContext(context);
        manager.Notify(1337, notification);
    }
}

主要活动:global::Xamarin.Forms.Platform.Android.FormsApplicationActivity{

MainActivity: global::Xamarin.Forms.Platform.Android.FormsApplicationActivity {

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        global::Xamarin.Forms.Forms.Init(this, bundle);
        LoadApplication(new App());                        
    }
}

关于如何解决的任何建议?对我来说，最大的问题是我需要在哪个对象上调用 removeView()?这个异常是在 LoadApplication(newApp()) 上抛出的；行在我的 MainActivity 中.

Any suggestions on how to resolve? For me the biggest question is what object do I need to call removeView() on? This exception is thrown on the LoadApplication(newApp()); line in my MainActivity.

由于完整的堆栈跟踪真的很长，请单击此处获取 pastebin.

Since a full stack trace is really long, click here for the pastebin.

推荐答案

自己发现了答案.

在 AlarmReceiver 中，我需要做的就是:

inside the AlarmReceiver all I need to do was this:

resultIntent.SetFlags(ActivityFlags.Singletop);

resultIntent.SetFlags(ActivityFlags.Singletop);

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