Android: Master Navigation page displayed as third bottom tabbar item

[alekseevabah]

Description

We have the following pages structure: MainPage = MasterDetailPage:

• Master: a Navigation page with a single Content page
• Detail: a Tabbed page with 5 tabs: --- each tab is a Navigation page with a single Content page in it

Toolbar placement is set to Bottom for Android.

Steps to Reproduce

Run the attached test project on android device.

Expected Behavior

Third bottom tabbar item is displayed similar to other tabbar items. Master page is accessible via the hamburger icon.

Actual Behavior

Master page is displayed instead of third bottom tabbar item. Master page is not displayed when tapping on the hamburger icon.

Basic Information

• Version with issue: 4.3.0.908675
• Last known good version: 4.2.0.910310
• IDE: Visual Studio 2019 (16.4.0) for Windows
• Platform Target Frameworks:
  • Android: 9.0
• Nuget Packages: NETStandard.Library (2.0.3), Xamarin.Essentials (1.3.1)
• Affected Devices: HUAWEI VTR-L09 and others (we experienced this on multiple of our test devices)

Screenshots

Reproduction Link

AppWithMenuInsteadOfTabbedItem.zip

Notes

Looks like the issue was introduced with this pull request: https://github.com/xamarin/Xamarin.Forms/pull/6471 (we reverted this file and the bottom tabbar behaved correctly). Using random numbers as Ids for MasterDetailContainer also solves the issue (looks like Master navigation page gets the same ID assigned as third bottom tabbar item?).

[PureWeen]

@kvpt

[kvpt]

I use this code in my apps for more than 6 months, but I don't use bottom bar. I will look at it, thanks for the reproduction. I will add an UI test at the same time as the fix.

[kvpt]

@alekseevabah You was right, the issue is caused because BottomNavigationItem id was set manually in a for loop. So the GeneratedViewId of the MasterDetailPageContainer was the same. But why it's working in all others cases and not this one 🤷‍♂.