[Bug] TabView - Tab is not being selected

[MauricioCodeguez]

Description

The penultimate tab isn't being selected after selecting the last one

Steps to Reproduce

1. Download the sample code provided in the re-production link.
2. Run the sample on an Android device or simulator.
3. Tap on the last tab.
4. Try selecting the last but one tab.

Expected Behavior

Tab is selected

Actual Behavior

Tab isn't being selected

Basic Information

• Version with issue: XF 4.8.0.1687
• Last known good version: N/A
• Platform Target Frameworks:
  • Android: 9, 10

Reproduction imagery

Reproduction Link

https://github.com/MauricioCodeguez/TabViewDemo

[Cfun1]

You have specified versin with issue for Xamarin.Forms only, could you specify XamarinCommunityToolkit version as well ?

[MauricioCodeguez]

@Cfun1
The XamarinCommunityToolkit version is 1.0.0-pre5

[jfversluis]

@MauricioCodeguez would you be so kind to try pre6 that has been released this week and verify this is still an issue?

cc: @jsuarezruiz

[MauricioCodeguez]

@jfversluis I have tested on the latest version of the XamarinCommunityToolkit (pre6) and XF (5.0.0.1791-pre5). Unfortunately I am still having the same issue as before

[jsuarezruiz]

@MauricioCodeguez Thanks for the feedback. Will review the issue.

[petrofahed]

I am having the same issue here.
It could be easily reproduced on the xct.Sample / CustomTabsPage.xaml

• Add new <xct:TabViewItem Text="Tab5" ....>
• If you select the last Tab then tap tab-1 cannot be selected directly, you need to select other tabs to reenable it
• Add more tabs on the right side, all tab-1 tap has an issue

So the main issue is after adding TabViewItem on the right side of the FAB

[MauricioCodeguez]

@jsuarezruiz Is there any news about this issue or a workaround that could be used to avoid the problem?

[gresolio]

The issue can be easily reproduced if the TabItems[0] has no content:

var customItemNoContent = new TabViewItem { Text = "Custom", Content = null };
var regularItem1 = new TabViewItem { Text = "Tab1", Content = new Label { Text = "Content1" } };
var regularItem2 = new TabViewItem { Text = "Tab2", Content = new Label { Text = "Content2" } };
var regularItem3 = new TabViewItem { Text = "Tab3", Content = new Label { Text = "Content3" } };
var regularItem4 = new TabViewItem { Text = "Tab4", Content = new Label { Text = "Content4" } };

var tabView = new TabView
{
    TabItems =
    {
        customItemNoContent,
        regularItem1,
        regularItem2,
        regularItem3,
        regularItem4,
    }
};

TabViewItem.TabTappedEventHandler onTabTapped = (_, e)
    => Debug.WriteLine($"TabTapped {e.Position}");

TabView.TabSelectionChangedEventHandler onSelectionChanged = (_, e)
    => Debug.WriteLine($"SelectionChanged {e.OldPosition} {e.NewPosition}");

tabView.SelectionChanged += onSelectionChanged;
customItemNoContent.TabTapped += onTabTapped;
regularItem1.TabTapped += onTabTapped;
regularItem2.TabTapped += onTabTapped;
regularItem3.TabTapped += onTabTapped;
regularItem4.TabTapped += onTabTapped;

Log with customItemNoContent at index 0:

TabTapped 1
SelectionChanged 0 1
TabTapped 2
SelectionChanged 1 2
SelectionChanged 2 1 // SelectionChanged twice
TabTapped 3
SelectionChanged 1 3
SelectionChanged 3 2
TabTapped 2 // Cannot return to index tab-1
TabTapped 2
TabTapped 2

Log without customItemNoContent, all items have content, everything works as expected:

TabTapped 1
SelectionChanged 0 1
TabTapped 2
SelectionChanged 1 2
TabTapped 1
SelectionChanged 2 1
TabTapped 0
SelectionChanged 1 0

My use case: two custom elements on the sides without content (status ico + button) and the regular tab items in the middle:
x Tab1 Tab2 Tab3 x

At the moment I cannot implement this layout due to the tab switching issue.

Xamarin.Forms v5.0.0.1829-pre6
Xamarin.CommunityToolkit v1.0.0-pre6

[PrajeetShrestha]

Just tried the TabView from, Xamarin.CommunityToolkit (1.0.0) Stable. This issue still exists. When we select the last TabViewItem, we can't select the second last TabViewItem. Even in the demo given by @davidortinau
here: https://github.com/davidortinau/LosGatos this issue exists. Hoping for the fix soon :) @jsuarezruiz.