Xamarin 在通知点击时形成打开视图模型 [英] Xamarin forms open view model on notification tap

问题描述

我正在使用此代码在通知栏中显示通知.当通知被点击时，主要活动被启动.是否可以使用 MvvmCross 在 Xamarin 表单应用程序中启动视图模型而不是活动.

I am using this code to show notification in notification bar. When the notification is tapped, main activity is launched. Is it possible to launch the view model instead of activity in Xamarin forms app with MvvmCross.

 Intent notificationIntent = new Intent(context,typeof(MainActivity));
    notificationIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP |                                Intent.FLAG_ACTIVITY_SINGLE_TOP);      
   PendingIntent pIntent = PendingIntent.getActivity(context, code,
            notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    NotificationManager manager = (NotificationManager) context
            .getSystemService(Context.NOTIFICATION_SERVICE);
    NotificationCompat.Builder notify = new NotificationCompat.Builder(
            context);

    notify.setContentIntent(pIntent);
    notify.setSmallIcon(R.drawable.app_icon);
    notify.setContentTitle("Title");
    manager.notify(reqCode, notify.build());

推荐答案

我的想法是利用 PutExtra 与 消息中心.

首先，您在通知栏中显示通知:

First, you show the notification in the notification bar:

Intent intent = new Intent(Forms.Context, typeof(MainActivity));
if (openPage)
{
    intent.SetFlags(ActivityFlags.SingleTop);
    intent.PutExtra("OpenPage", "SomePage");
}

const int pendingIntentId = 0;
PendingIntent pendingIntent = PendingIntent.GetActivity(Forms.Context, pendingIntentId, intent, PendingIntentFlags.OneShot);

var nMgr = (NotificationManager)Android.App.Application.Context.GetSystemService(Context.NotificationService);
Notification.Builder notBuilder = new Notification.Builder(Android.App.Application.Context)
    .SetContentIntent(pendingIntent)
    .SetContentTitle("SomeApp")
    .SetContentText(message)
    .SetDefaults(NotificationDefaults.Sound | NotificationDefaults.Vibrate)
    .SetSmallIcon(Resource.Drawable.ic_launcher)
    .SetAutoCancel(true);

var notification = notBuilder.Build();
nMgr.Notify(0, notification);

在 MainActivity.cs 中检查额外的内容:

In MainActivity.cs you check for the extra content:

protected override void OnNewIntent(Intent intent)
{
    // Send message to the PCL (XF) if a certain page should be opened.
    if (intent.HasExtra("OpenPage"))
    {
        string pageName = intent.GetStringExtra("OpenPage") ?? "None";

        if (pageName != "None")
        {
            var message = new OpenPageMessage { PageName = pageName };
            MessagingCenter.Send(message, Message.Msg_OpenPage);
        }
    }

    base.OnNewIntent(intent);
}

您的中央导航实例(例如 MainPage)订阅此消息:

And your central navigation instance (e.g. MainPage), subscribes to this message:

MessagingCenter.Subscribe<Message.OpenPageMessage>(this, Message.Msg_OpenPage, (async) message =>
{
    // Loads a certain page if a message is received

    switch (message.PageName)
    {
        case "SomePage":
            await Navigation.PushModalAsync(new SomePage(), true);
            break;
        default:
            break;
    }
});

此外，这是我的Message.cs:

public class Message
{
    public const string Msg_OpenPage = "OpenPage";

    public class OpenPageMessage {
        public string PageName { get; set; }
    }
}

借助此来源.

编辑

如果您一次有多个推送通知，其中的通知会被覆盖，则会出现问题.可以使用不同的 requestCode 或使用 FLAG_UPDATE_CURRENT.

There are issues if you have multiple push notifications at a time, where notfications where overwritten. One could use a different requestCode or use FLAG_UPDATE_CURRENT.

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