[iOS] Fix Background issue in Button CustomRenderer

[jsuarezruiz]

Description of Change

Fix Background issue in Button CustomRenderer in iOS.

Issues Resolved

• fixes [Bug] XF 4.8 breaks custom renderer (Button) background color on iOS #12372

API Changes

None

Platforms Affected

• iOS

Behavioral/Visual Changes

None

Before/After Screenshots

Testing Procedure

Launch Core Gallery and navigate to the issue 12372. If you can see the background color of the custom Button below, the test has passed.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[PureWeen]

Should this be using a locally stored _defaultBackgroundColor instead of a bool check?

Basically how SetBackgroundColor is setup?

		protected override void SetBackgroundColor(Color color)
		{
			if (IsElementOrControlEmpty)
				return;
#if __MOBILE__
			if (color == Color.Default)
				Control.BackgroundColor = _defaultColor;
			else
				Control.BackgroundColor = color.ToUIColor();
#else
			Control.Layer.BackgroundColor = color == Color.Default ? _defaultColor : color.ToCGColor();
#endif
		}

[jsuarezruiz]

Yes, we already have a variable with the default color, the new bool variable only indicates if a brush is being used or not. We have two properties Background and BackgroundColor and this variable just indicate us when we can update the background using a color.

[PureWeen]

This still feels a little bit off to me. _useBackgroundBrush can only ever be toggled one direction so once it's true it's always true

So, after you set the Background to something it becomes impossible to use the BackgroundColor. If you set the Background back to "Default" then use the BackgroundColor property it'll just set the Control.BackgroundColor to null

        private void Button_Clicked(object sender, EventArgs e)
        {
           // this code stops working after you've set the Background to a brush. 
            btnMe.Background = SolidColorBrush.Default;
            btnMe.BackgroundColor = Color.Green;
        }

        private void Button_Clicked2(object sender, EventArgs e)
        {
            btnMe.Background = SolidColorBrush.Purple;
        }

Is this expected behavior?

[jsuarezruiz]

Shane, I totally see your feedback and I understand it. I have applied changes with a different approach with more sense.
Now, the custom renderer works and also your case works without using any internal variable etc.