.NET MAUI: The tab switching functionality is not working properly on the iOS platform

Question

We have three tabs in our application. Initially, switching from the first tab to the third tab works fine. However, when trying to switch back from the third tab to the first tab, it does not work as expected. Instead, it navigates from the third tab to the second tab, and only then allows switching to the first tab. This issue occurs only on the iOS platform and works fine on Android Platform.

The three tabs are implemented as ContentView pages and are integrated into a CarouselPage. After logging into the app, the three tabs appear. From the CarouselPage, I am using WeakReferenceMessenger to handle the swiping between tabs starting from the first page. Below is a sample code snippet for sending the WeakReferenceMessenger:

<CarouselView 
    x:Name="carouselView"
    CurrentItemChanged="OnCurrentItemChanged"
    Loop="False">
    <CarouselView.ItemsSource>
        <x:Array Type="{x:Type ContentView}">
            <control:HomePage/>
            <control:FriendsPage/>
            <control:HistoryPage/>
        </x:Array>
    </CarouselView.ItemsSource>
    <CarouselView.ItemTemplate>
        <DataTemplate>
            <ContentView Content="{Binding}"/>
        </DataTemplate>
    </CarouselView.ItemTemplate>
</CarouselView>

void OnCurrentItemChanged(object sender, CurrentItemChangedEventArgs e)
{
    try
    {
        Debug.WriteLine("Position:>>" + carouselView.Position);
        int index = carouselView.Position;
        AddWeakReferenceMessenger(index);
    }
    catch (Exception ex)
    {
        Debug.WriteLine("Exception:>>" + ex);
    }
}

private void AddWeakReferenceMessenger(int index)
{
    try
    {
        if (index == 0)
        {
            WeakReferenceMessenger.Default.Send(new HomeTabChangeMessage("home_tab"));
        }
        else if (index == 1)
        {
            WeakReferenceMessenger.Default.Send(new HomeTabChangeMessage("friends_tab"));
        }
        else if (index == 2)
        {
            WeakReferenceMessenger.Default.Send(new HomeTabChangeMessage("history_tab"));
        }
    }
    catch (Exception ex)
    {
        Debug.WriteLine("Exception:>>" + ex);
    }
}

This WeakReferenceMessenger is registered to each tab. Below is a sample code snippet for third tab to subscribe to the message.

WeakReferenceMessenger.Default.Register<HomeTabChangeMessage>(this, async (r, m) =>
{
    if (m.Value == "history_tab")
    {
        Debug.WriteLine("isHistoryLoaded:>>" + Utility.isHistoryLoaded);
        if (!Utility.isHistoryLoaded)
        {
            UserDialogs.Instance.ShowLoading("");
            await Task.Delay(TimeSpan.FromSeconds(0.25));
            Utility.isHistoryLoaded = true;
            await Task.Run(async () => await SetHistoryListItems());
        }
        WeakReferenceMessenger.Default.Unregister<HomeTabChangeMessage>(this);
    }
});

Below is a sample code snippet for sending the WeakReferenceMessenger for switching from third tab to first tab:

public void ShowHome(object sender, EventArgs args)
{
    WeakReferenceMessenger.Default.Send(new TabSelectionMessage("child-0"));
}

Below is a sample code snippet for first tab to subscribe to the message.

WeakReferenceMessenger.Default.Register<TabSelectionMessage>(this, (r, m) =>
{
    try
    {
        string[] childArray = m.Value.Split("-");
        if (childArray[0] == "child")
        {
            carouselView.ScrollTo(Int32.Parse(childArray[1]));
            AddWeakReferenceMessenger(Int32.Parse(childArray[1]));
        }
    }
    catch (Exception ex)
    {
        Debug.WriteLine("TabSelectionException>>:" + ex);
    }
});

Can u please provide a solution for this issue?

Answer 1

If the issue is specific to iOS, you might need to implement platform-specific code to handle the tab switching. You can use conditional compilation to include iOS-specific logic.

implement platform-specific code in .NET MAUI:

C# code

#if IOS

// iOS-specific code

#endif

Another things you can do

1. Check CarouselView behavior on iOS

Ensure that CarouselView is behaving as expected on iOS. Sometimes platform-specific behaviors can cause unexpected issues. You might want to test the CarouselView without the WeakReferenceMessenger to see if the issue persists.

2. Update to the Latest Version

Make sure you are using the latest version of .NET MAUI and all related libraries. There might some bugs.

!Manual Tab Switching

Consider manually setting the CurrentItem of the CarouselView instead of relying solely on the CurrentItemChanged event. This can give you more control over the tab switching process.

please try once this code:

I found this code from a resource put my some code and generate some manualSwitching problem code from the AI

<CarouselView

x:Name="carouselView"

CurrentItemChanged="OnCurrentItemChanged"

Loop="False">

<CarouselView.ItemsSource>

    <x:Array Type="{x:Type ContentView}">

        <control:HomePage/>

        <control:FriendsPage/>

        <control:HistoryPage/>

    </x:Array>

</CarouselView.ItemsSource>

<CarouselView.ItemTemplate>

    <DataTemplate>

        <ContentView Content="{Binding}"/>

    </DataTemplate>

</CarouselView.ItemTemplate>

</CarouselView>

void OnCurrentItemChanged(object sender, CurrentItemChangedEventArgs e)

{

try

{

    Debug.WriteLine("Position:>>" + carouselView.Position);

    int index = carouselView.Position;

    AddWeakReferenceMessenger(index);

}

catch (Exception ex)

{

    Debug.WriteLine("Exception:>>" + ex);

}

}

private void AddWeakReferenceMessenger(int index)

{

try

{

    string tabName = index switch

    {

        0 => "home_tab",

        1 => "friends_tab",

        2 => "history_tab",

        _ => string.Empty

    };

    if (!string.IsNullOrEmpty(tabName))

    {

        WeakReferenceMessenger.Default.Send(new HomeTabChangeMessage(tabName));

    }

}

catch (Exception ex)

{

    Debug.WriteLine("Exception:>>" + ex);

}

}