[Bug] The NavigationBar fails to refresh when the existing child of a TabbedPage is substituted with a different NavigationPage.

[HMorales-ChipSoft]

Description

Hi,

In our scenario, every tab within the TabbedPage contains a distinct NavigationPage. However, when an existing NavigationPage is substituted with a new one, the NavigationBar ceases to refresh. It's important to note that this issue only occurs when the TabbedPage is presented as a Modal. On iOS, the functionality operates as anticipated.

Steps to Reproduce

I have composed the following code to replicate our scenario:

The MainPage includes a button. When pressed, another MainPage will be presented as a Modal, and the scenario described above will repeat.

Expected Behavior

Actual Behavior

Link to public reproduction project repository

https://github.com/HMorales-ChipSoft/Maui_Issues/tree/main/ReproMaui

Version with bug

8.0.40 SR5

Is this a regression from previous behavior?

Yes, this used to work in Xamarin.Forms

Last version that worked well

Unknown/Other

Affected platforms

Android, Windows

Affected platform versions

No response

Did you find any workaround?

Unfortunately no.

Relevant log output

No response

[github-actions]

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Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it. Thank you!

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[ninachen03]

Verified this issue with Visual Studio 17.11.0 Preview 1.1(8.0.40 & 8.0.3). Can repro on android platform with sample project.

[HMorales-ChipSoft]

Any progression or workaround?

[NanthiniMahalingam]

Sample level fix

• When dynamically adding a new tapped page to the root of the content page, we can use the PushModalAsync method because content page is not possible to set the tapped page.
• If we need to push another navigation page onto the tapped page, we must create a new instance of the tapped page using the existing instance, then add the navigation page and its content.
• After initializing tapped page, we can push the navigation page using PushModalAsync method.
• Now, the first and second navigation pages are updated by providing a task delay duration.

public class MainPageViewModel
{
        public MainPageViewModel()
        {
                ShowModalCommand = new Command(async obj =>
                {
                        Microsoft.Maui.Controls.TabbedPage tabbedPage = new Microsoft.Maui.Controls.TabbedPage
                        {
                                Children =
                                        {
                                                new NavigationPage(new MainPage { Title = "Main_Start_Modal_NavigationBar" }) { BarBackgroundColor = Colors.Red,  Title = "Start_Modal_NavigationBar"  }
                                        }
                        };

        //tabbedPage.On<Microsoft.Maui.Controls.PlatformConfiguration.Android>().SetToolbarPlacement(ToolbarPlacement.Bottom);

        if (Microsoft.Maui.Controls.Application.Current?.MainPage?.Navigation is INavigation navigation)
        {
                await navigation.PushModalAsync(tabbedPage);
        }

        await Task.Delay(3000);

        tabbedPage = new Microsoft.Maui.Controls.TabbedPage
        {
                Children =
                        {
                                new NavigationPage(new MainPage { Title = "Main_New_Modal_NavigationBar" }) { BarBackgroundColor = Colors.Green,  Title = "New_Modal_NavigationBar"  }
                        }
        };

        // tabbedPage.Children[0] = new NavigationPage(new MainPage { Title = "Main_New_Modal_NavigationBar" }) { BackgroundColor = Colors.Yellow , Title = "New_Modal_NavigationBar" };

        if (Microsoft.Maui.Controls.Application.Current?.MainPage?.Navigation is INavigation navigation1)
        {
                await navigation1.PushModalAsync(tabbedPage);
        }

        });
        }

        public ICommand ShowModalCommand { get; set; }
}