[Bug] [iOS] NavigationBar resetting TextColor to black at every change of BarBackgroundColor

[luccasclezar]

Description

Well, basically the PropertyChanged of BarBackgroundColor resets the NavigationBar's Appearance instead of modifying the current one. You can see this happening at this line:

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/NavigationRenderer.cs

Line 631 in 6a23b84

var navigationBarAppearance = new UINavigationBarAppearance();

If this line is changed to:

var navigationBarAppearance = NavigationBar.StandardAppearance;

The bug is gone.

I can't provide any repro projects as I'm experiencing this issue on a commercial app and couldn't reproduce the issue on a new project, but just looking at the line I linked it's possible to understand that the code should be like I said if nothing is meant to be overwritten.

I tested this modification with the said commercial app and it's working. 🙂

Basic Information

• Version with issue: 4.5
• Platform Target Frameworks:
  • iOS: 13 (13.3.1)

Workaround

On a new NavigationRenderer's PropertyChanged, copy the code of UpdateBarBackgroundColor (

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/NavigationRenderer.cs

Line 618 in 6a23b84

void UpdateBarBackgroundColor()

) and replace new UINavigationBarAppearance() to NavigationBar.StandardAppearance as I said in the description.

[vniehues]

I have the exact same issue. I use the app resources to theme my app based on the OS theme (android 10 & iOS 13) and while everything else changes perfectly, the NavigationBar is off.
Switching the page and going back will result in the correct colors showing again.