Xamarin表单：棱镜：Android：MainActivity：点击推送通知：Android上不支持PushAsync，请使用NavigationPage

Question

我正在尝试使用带有Prism MVVM，Azure和FCM的Xamarin Forms实现基本推送通知示例。

我收到通知，但在点击通知时无法导航到特定页面。

在应用程序运行时或在后台（未关闭）时尝试基本功能。

它引发了一个例外“Android上全局不支持PushAsync，请使用导航页面”

ExploreXam.App.Current.MainPage.Navigation.PushAsync(page);

[Activity(LaunchMode = LaunchMode.SingleTask, MainLauncher = true]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    internal static readonly string CHANNEL_ID = "explore_xamarin";
    internal static readonly int NOTIFICATION_ID = 1029;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        CreateNotificationChannel();
        global::Xamarin.Forms.Forms.Init(this, bundle);
        LoadApplication(new App());
    }
    protected override void OnNewIntent(Intent intent)
    {
        base.OnNewIntent(intent);
        Intent = intent;
        NotificationClickedOn(intent);
    }
    private void NotificationClickedOn(Intent intent)
    {
        if (intent.Action == ExploreXamFirebaseMessagingService.ExploreXamNotification && intent.HasExtra("XamId"))
        {
            var page = new Xamarin.Forms.NavigationPage(new SpecificPage());
            Xamarin.Forms.Application.Current.MainPage.Navigation.PushAsync(page);
            ExploreXam.App.Current.MainPage.Navigation.PushAsync(page);
        }
    }
}

public partial class App : PrismApplication
{
    public bool navigating;

    public App(IPlatformInitializer initializer = null, bool shallNavigate=false) : base(initializer)
    {
        navigating = shallNavigate;
    }
    protected async override void OnInitialized()
    {
        BlobCache.ApplicationName = "ExploreXam";
        InitializeComponent();
        FlowListView.Init();
        //await  NavigationService.NavigateAsync("LoginPage");
        await NavigationService.NavigateAsync("NavigationPage/LoginPage");
    }
    protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {
        //mapping 
    }
}

请问有什么好处吗？

Answer 1

发生这种情况的原因是因为你的Application.Current.MainPage不是导航页面而是ContentPage（我假设）

将您的初始MainPage包装在NavigationPage中，如下所示，它应该可以工作

在App.xaml.cs中

     MainPage= new NavigationPage(new FirstPage());

Answer 2

您可以访问Prims的NavigationService实例来实现您要执行的操作。但是，它是受保护的财产。所以，首先你必须通过你的App类公开它，如下所示：

public new INavigationService NavigationService => base.NavigationService;

现在，您只需通过应用程序在应用程序中引用它，即可从应用程序的任何位置访问NavigationService：

(Xamarin.Forms.Application.Current as App).NavigationService.NavigateAsync("your/page/path");

所以，你的App类看起来像这样：

public partial class App : PrismApplication
{
    public new INavigationService NavigationService => base.NavigationService;
    public bool navigating;

    public App(IPlatformInitializer initializer = null, bool shallNavigate=false) : base(initializer)
    {
        navigating = shallNavigate;
    }

    protected async override void OnInitialized()
    {
        BlobCache.ApplicationName = "ExploreXam";
        InitializeComponent();
        FlowListView.Init();
        //await  NavigationService.NavigateAsync("LoginPage");
        await NavigationService.NavigateAsync("NavigationPage/LoginPage");
    }

    protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {
        //mapping 
    }
}

并且您的NotificationClickOn函数将变为类似于：

private async void NotificationClickedOn(Intent intent)
{
    if (intent.Action == ExploreXamFirebaseMessagingService.ExploreXamNotification && intent.HasExtra("XamId"))
    {
        var navigationService = (Xamarin.Forms.Application.Current as ContosoCookbook.App).NavigationService;
        await navigationService.NavigateAsync("YourNavigationPage/SpecificPage");
    }
}

Answer 3

我同意@chaosifier。在App.xaml.cs文件中创建一个公共INavigationService，然后在OnInitialized（）方法中创建public property = the base.NavigationService;

public INavigationService PrismNavigation { get; private set; }

protected override async void OnInitialized()
{
    InitializeComponent();
    PrismNavigation = base.NavigationService;
}

然后从MainActivity.cs文件中，您可以使用类似的东西进行导航

(Xamarin.Forms.Application.Current as App).PrismNavigation.NavigateAsync(nameof(ShowAlertsDetailPage));

我希望这有帮助。