Xamarin.forms: [Visual] [iOS] [Material] Button.BackgroundColor not working in C#

[xXdRaGoNrIdDeRXx]

Description

If i have a Button on the screen with Visual="Material" when i change BackgroundColor property of the button in code the change does nothing on iOS, this works if the button is Visual="Default", and works fine on Android for both.

Steps to Reproduce

1. Open a xamarin project with iOS
2. place a button on the screen with Visual="Material"
3. change button's background colour (toggle between 2 colours) in code using button click event

Expected Behavior

The background colour should toggle/change every click

Actual Behavior

Nothing happens

Basic Information

• Version with issue: v3.6.0.264807
• Last known good version: N/A
• IDE: Visual Studio 2017: 15.9.10
• Platform Target Frameworks:
  
  
  
  • iOS: 12.2
  
  
• Affected Devices:
  Simulator and physical

Reproduced in TheLittleThingsPlayground by simply adding this to ButtonsPage.xaml.cs Constructor:

``` C#
Task.Run( async () =>
{
while( true )
{
if( testColorChange.BackgroundColor == Color.Black )
{
testColorChange.BackgroundColor = Color.Green;
}
else
{
testColorChange.BackgroundColor = Color.Black;
}

await Task.Delay( 1000 );

}
} );
```

and changing any button to have the x:Name="testColorChange"

[xXdRaGoNrIdDeRXx]

has there been any update on this issue?

[darshanio]

Replicated.

System Information
Visual Studio: 16.1.1
Xamarin.iOS and Xamarin.Mac SDK version: 12.10.0.153(750a879)
Xamarin.Forms version: 4.0.0.425677
Xamarin.Forms.Visual.Material version: 4.0.0.425677

---

Implementing a custom renderer solves this problem.

internal class CustomMaterialButtonRenderer : MaterialButtonRenderer
{
    protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        base.OnElementPropertyChanged(sender, e);

        if (e.PropertyName == nameof(Element.BackgroundColor))
        {
            Control.BackgroundColor = Element.BackgroundColor.ToUIColor();
        }
    }
}

[davidortinau]

Happening in 4.2-nightly. I wonder if it's the material SemanticColorScheme check...wild guess. https://github.com/xamarin/Xamarin.Forms/blob/master/Xamarin.Forms.Material.iOS/MaterialButtonRenderer.cs#L149

[kicsiede]

for those wondering how to export the workaround custom renderer (@darshanio ) to override material renderer only:

[assembly: ExportRenderer(typeof(Button), typeof(CustomRenderers.iOS.CustomMaterialButtonRenderer), new[] { typeof(VisualMarker.MaterialVisual) })]

[xXdRaGoNrIdDeRXx]

I don't like the idea of requiring to use a custom renderer for this, Is there an eta on official fix from Xamarin.Forms side?

[Raystorm7]

HI all!
Any news on this?

Thank you!

[xXdRaGoNrIdDeRXx]

@PureWeen, it has been a few months has there been any development on this issue?