c# - 如何使用MvvmCross 5 IMvxNavigationService获取PendingIntent？

原文 标签 c# xamarin.android mvvmcross

我在mvvmcross 4.x中使用了一个方法，该方法与NotificationCompat.Builder一起用于设置通知的PendingIntent以在用户单击通知时显示viewmodel。我试图将此方法转换为使用mvvmcross 5.xIMvxNavigationService但看不到如何设置表示参数，也看不到如何使用新的导航api获取PendingIntent。

private PendingIntent RouteNotificationViewModelPendingIntent(int controlNumber, RouteNotificationContext notificationContext, string stopType)
{
    var request = MvxViewModelRequest<RouteNotificationViewModel>.GetDefaultRequest();
    request.ParameterValues = new Dictionary<string, string>
    {
        { "controlNumber", controlNumber.ToString() },
        { "notificationContext", notificationContext.ToString() },
        { "stopType", stopType }
    };
    var translator = Mvx.Resolve<IMvxAndroidViewModelRequestTranslator>();
    var intent = translator.GetIntentFor(request);
    intent.SetFlags(ActivityFlags.NewTask | ActivityFlags.ClearTask);

    return PendingIntent.GetActivity(Application.Context,
                                     _notificationId,
                                     intent,
                                     PendingIntentFlags.UpdateCurrent);
}

当我单击通知时，RouteNotificationViewModel确实出现，但未调用Prepare和Initialize。将此方法从MVVMcross 4.x导航样式转换为MVVMcross 5.x导航样式需要什么？

在mvvmcross 5+中可以做到这一点，但它不像以前那样干净。
对于初学者，您需要为活动指定单顶启动模式：

[Activity(LaunchMode = LaunchMode.SingleTop, ...)]
public class MainActivity : MvxAppCompatActivity

生成如下挂起的通知内容：

var intent = new Intent(Context, typeof(MainActivity));
intent.AddFlags(ActivityFlags.SingleTop);
// Putting an extra in the Intent to pass data to the MainActivity
intent.PutExtra("from_notification", true);
var pendingIntent = PendingIntent.GetActivity(Context, notificationId, intent, 0);

现在，在仍然允许使用MVVMcross导航服务的情况下，有两个地方可以从mainActivity处理此意图：
如果在单击通知时应用程序未运行，则将调用OnCreate。

protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);
    if (bundle == null && Intent.HasExtra("from_notification"))
    {
        // The notification was clicked while the app was not running. 
        // Calling MvxNavigationService multiple times in a row here won't always work as expected. Use a Task.Delay(), Handler.Post(), or even an MvvmCross custom presentation hint to make it work as needed.
    }
}

如果在单击通知时应用程序正在运行，则将调用OnNewIntent。

protected override void OnNewIntent(Intent intent)
{
    base.OnNewIntent(intent);
    if (intent.HasExtra("from_notification"))
    {
        // The notification was clicked while the app was already running.
        // Back stack is already setup.
        // Show a new fragment using MvxNavigationService.
    }
}