Problem Loading MainPage

Question

Problem Loading MainPage

Asgar Ali 86

I have this code to set the Mainpage in my application.

 public async void LoadMainPage()  
        {  
            try  
            {  
                bool signedin = false;  
                signedin = Auth.IsUserSignedIn();  
                   
                if (!signedin)  
                {   
                MainPage = new NavigationPage(new MainPage());  
                }  
                else if (signedin && !(await Firestore.IsUserRegistered()))  
                    MainPage = new NavigationPage(new RegistrationPage());  
                else if (signedin && (await Firestore.IsUserRegistered()))  
                {   
                    MainPage = new NavigationPage(new FlyoutPage1());  
                }    
            }  
            catch (Exception ex) { await App.Current.MainPage.DisplayAlert("Error", ex.Message, "OK"); }  
        }  
         
    }

on starting the application the registrationpage and the flyoutpage fails to load properly.
it appears only when i tap the triple line icon on my phone wait for some time and tap the application again to launch it.
the code for Firestore.IsUserRegistered is as below

   public async Task<bool> IsUserRegistered()  
        {  
             
           FirebaseFirestore collection = FirebaseFirestore.Instance;  
            string email = FirebaseAuth.Instance.CurrentUser.Email;  
            collection.Collection("User").WhereEqualTo("Email", email)  
                    .Limit(1).Get()  
                    .AddOnSuccessListener(this);  
            for (int i = 0; i < 25; i++)  
            {  
                await Task.Delay(100);  
                if (isregistered) break;  
            }  
            return isregistered;  
        }  
  public void OnSuccess(Java.Lang.Object result)  
        {  
            if (result == null) return;  
            else  
            {  
                var documents = (QuerySnapshot)result;  
                isregistered = ! documents.IsEmpty;  
            }  
             
        }

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-09-30T05:52:02.637+00:00

It should be caused by await Task.Delay(100);, please delete it.

In addition, You could use a variable to receive the value from Firestore.IsUserRegistered() to prevent it from being executed twice.
Asgar Ali 86 Reputation points

2022-10-01T05:27:56.557+00:00

I removed awit Task.Delaay(100) . and aded a variable to recieve value from Firestore.IsUserRegistered.

Now the IsuserUserRegistered aiways returns false even if the user is Registered.
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-10-04T08:27:38.837+00:00

You could use Task.Run(async () => await LoadMainPage()).Wait(); to execute the function, if await Task.Delay(100) is necessary.
Asgar Ali 86 Reputation points

2022-10-04T18:59:09.427+00:00

if iI use Task.Run(async () => await LoadMainPage()).Wait(); thenIsUserRegistered always returns false.
if i remove the Wait() method and simply use Task.Run(async () => await LoadMainPage()); then i get Java.Lang.IllegalArgumentException no view found for id 0x1(Unknown).
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-10-06T06:21:40.123+00:00

Task.Wait() means it waits for the Task to complete execution. Please refer to Task.Wait Method.

It's strange that isregistered is still false when the LoadMainPage() method execution ends.

For further investigation, could you please provide more detailed information about if you set breakpoint in the OnSuccess(Java.Lang.Object result) method, will the program execute it?
Asgar Ali 86 Reputation points

2022-10-06T12:37:30.107+00:00

I place two breakpoints on IsUserRegistered() and on OnSuccess(Java.Lang.Object result)
when i use LoadMainPage() the OnSuccess(Java.Lang.Object result)) is hit And the isregistered returns true;When i use Task.Run(async()=> await LoadMainPage()).Wait();First the sUserRegistered() is hit and the isregistered returns false. after that if i hit the continue button OnSuccess(Java.Lang.Object result) is hit and the IsRegistered returns true.

1 answer

Your answer

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-09-30T05:52:02.637+00:00

It should be caused by await Task.Delay(100);, please delete it.

In addition, You could use a variable to receive the value from Firestore.IsUserRegistered() to prevent it from being executed twice.
Asgar Ali 86 Reputation points

2022-10-01T05:27:56.557+00:00

I removed awit Task.Delaay(100) . and aded a variable to recieve value from Firestore.IsUserRegistered.

Now the IsuserUserRegistered aiways returns false even if the user is Registered.
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-10-04T08:27:38.837+00:00

You could use Task.Run(async () => await LoadMainPage()).Wait(); to execute the function, if await Task.Delay(100) is necessary.
Asgar Ali 86 Reputation points

2022-10-04T18:59:09.427+00:00

if iI use Task.Run(async () => await LoadMainPage()).Wait(); thenIsUserRegistered always returns false.
if i remove the Wait() method and simply use Task.Run(async () => await LoadMainPage()); then i get Java.Lang.IllegalArgumentException no view found for id 0x1(Unknown).
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-10-06T06:21:40.123+00:00

Task.Wait() means it waits for the Task to complete execution. Please refer to Task.Wait Method.

It's strange that isregistered is still false when the LoadMainPage() method execution ends.

For further investigation, could you please provide more detailed information about if you set breakpoint in the OnSuccess(Java.Lang.Object result) method, will the program execute it?
Asgar Ali 86 Reputation points

2022-10-06T12:37:30.107+00:00

I place two breakpoints on IsUserRegistered() and on OnSuccess(Java.Lang.Object result)
when i use LoadMainPage() the OnSuccess(Java.Lang.Object result)) is hit And the isregistered returns true;When i use Task.Run(async()=> await LoadMainPage()).Wait();First the sUserRegistered() is hit and the isregistered returns false. after that if i hit the continue button OnSuccess(Java.Lang.Object result) is hit and the IsRegistered returns true.

Answer 1

Asgar Ali 86

I added a Splashscreen to the Application and called LoadMainPage() from the OnAppearing Method of the Page.Now everything is working Fine.

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,126 Reputation points Microsoft External Staff

2022-10-11T06:38:58.06+00:00

Thanks for your sharing.

Could you please convert this comment to an answer? It would be helpful for others who meet the same issue.

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Problem Loading MainPage

1 answer

Your answer