Receives a dynamic link and navigates to the desired page Xamarin.Form but Xamarin.Android is not working

Question

I want to write code that receives a dynamic link and navigates to the desired page.

So I wrote the below, and both iOS and Android receive it.

Xamarin.Form code

public partial class MainPage : ContentPage
    {

        public MainPage()
        {   
            InitializeComponent();
            MessagingCenter.Subscribe<App, TestModel>((App)Xamarin.Forms.Application.Current, "dynamicLink", getURl);
        }



        private  void getURl(App sourece, TestModel model)
        {   
            Console.WriteLine(model.page);
            Navigation.PushAsync(model.page);
        }
    }

Xamarin.Android code

class OnSuccessListner : Java.Lang.Object, IOnSuccessListener
    {
        void IOnSuccessListener.OnSuccess(Java.Lang.Object result)
        {
            var link = result.JavaCast<PendingDynamicLinkData>();
            Android.Net.Uri deeplink = null;
            if (link != null)
            {
                Console.WriteLine("received");
                deeplink = link.Link;
                Console.WriteLine($"{deeplink}");
                var Model = new TestModel();
                if (deeplink.Path == "/Test")
                {   

                   switch(deeplink.GetQueryParameter("ModelName"))
                    {
                        case "Test1":
                            Model = new TestModel { page = new Test1() };
                            break;
                        case "Test2":
                            Model = new TestModel { page = new Test2() };
                            break;
                        default:
                            Console.WriteLine("Not Value");
                            break;
                    }
                }

                MessagingCenter.Send((App)Xamarin.Forms.Application.Current, "dynamicLink", Model);
            }
        }

    }

Xamarin.iOS

public override bool ContinueUserActivity(UIApplication application, NSUserActivity userActivity, UIApplicationRestorationHandler completionHandler)
        {   

            return DynamicLinks.SharedInstance.HandleUniversalLink(userActivity.WebPageUrl, (dynamicLink, error) => {
                if (error != null)
                {
                    System.Console.WriteLine(error.LocalizedDescription);
                    return;
                }
                var compoents = new NSUrlComponents(dynamicLink.Url, false);
                var queryitems = compoents.QueryItems;
                var Model = new TestModel();
                if(compoents.Path == "/Test")
                {
                    var queryitem = (from item in queryitems
                                where item.Name == "ModelName"
                                select item).First();
                    if(queryitem != null)
                    {
                        switch (queryitem.Value)
                        {
                            case "Test1":
                                Model = new TestModel { page = new Test1() };
                                break;
                            case "Test2":
                                Model = new TestModel { page = new Test2() };
                                break;
                            default:
                                Console.WriteLine("Not Value");
                                break;
                        }
                    }
                }

                Console.WriteLine(dynamicLink);

                MessagingCenter.Send((App)Xamarin.Forms.Application.Current, "dynamicLink", Model);
                // Handle Universal Link
            });

However, on Android, there is a problem that MessagingCenter listens twice and an error of "System.InvalidOperationException: 'Page must not already have a parent.' "

So I modified the method. I change my Moethod like this.

private async void getURl(App sourece, TestModel model)
        {   

            if(Device.RuntimePlatform == Device.iOS)
            {
                Console.WriteLine($"{model.page} - iOS");
                await Navigation.PushAsync(model.page);
            } else
            {
                Console.WriteLine($"{model.page} - Android");
                await Navigation.PushAsync(model.page);
                MessagingCenter.Unsubscribe<App, TestModel >((App)Xamarin.Forms.Application.Current, "dynamicLink");

            }

        }

I posted the same question. https://stackoverflow.com/questions/68992245/receives-a-dynamic-link-and-navigates-to-the-desired-page-xamarin-form-but-xamar

MessagingCenter received it once, but it doesn't move to the page.

May I know what the problem is!?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

System.InvalidOperationException: 'Page must not already have a parent.

Hi, 22346713. This exception is caused when the navigation is executed multiple times. Here is a related case, you could refer to: https://github.com/xamarin/Xamarin.Forms/issues/3446#issuecomment-417149001

However, on Android, there is a problem that MessagingCenter listens twice

Does the iOS platform work fine? To perform the navigation in native project, you could call the function directly without using MessagingCenter. Try testing the following to check if it would work.

   void IOnSuccessListener.OnSuccess(Java.Lang.Object result)  
   {  
       var link = result.JavaCast<PendingDynamicLinkData>();  
       Android.Net.Uri deeplink = null;  
       if (link != null)  
       {  
           ...  
     
           //MessagingCenter.Send((App)Xamarin.Forms.Application.Current, "dynamicLink", Model);  
           App.Current.MainPage.Navigation.PushAsync(Model.page);  
       }  
   }  

Best Regards,

Jarvan Zhang

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