public static void UpdateBackground(this GradientDrawable gradientDrawable, Brush brush, int height, int width)
{
if (gradientDrawable == null || brush == null || brush.IsEmpty)
{
return;
}
if (brush is SolidColorBrush solidColorBrush)
{
Color bgColor = solidColorBrush.Color;
gradientDrawable.SetColor(bgColor.IsDefault ? Color.Default.ToAndroid() : bgColor.ToAndroid());
}
if (brush is LinearGradientBrush linearGradientBrush)
{
var p1 = linearGradientBrush.StartPoint;
var x1 = (float)p1.X;
var y1 = (float)p1.Y;
var p2 = linearGradientBrush.EndPoint;
var x2 = (float)p2.X;
var y2 = (float)p2.Y;
const double Rad2Deg = 180.0 / Math.PI;
var angle = Math.Atan2(y2 - y1, x2 - x1) * Rad2Deg;
var gradientBrushData = linearGradientBrush.GetGradientBrushData();
var colors = gradientBrushData.Item1;
if (colors.Length < 2)
{
return;
}
gradientDrawable.SetGradientType(GradientType.LinearGradient);
gradientDrawable.SetColors(colors);
gradientDrawable.SetGradientOrientation(angle);
}
if (brush is RadialGradientBrush radialGradientBrush)
{
var center = radialGradientBrush.Center;
float centerX = (float)center.X;
float centerY = (float)center.Y;
float radius = (float)radialGradientBrush.Radius;
var gradientBrushData = radialGradientBrush.GetGradientBrushData();
var colors = gradientBrushData.Item1;
if (colors.Length < 2)
{
return;
}
gradientDrawable.SetGradientType(GradientType.RadialGradient);
gradientDrawable.SetGradientCenter(centerX, centerY);
gradientDrawable.SetGradientRadius(Math.Max(height, width) * radius);
gradientDrawable.SetColors(colors);
}
}
protected override void OnElementChanged(ElementChangedEventArgs <Button> e)
{
base.OnElementChanged(e);
if (e.OldElement == null)
{
var button = Control;
// See ButtonRendererWithNavFix.cs
CustomClickHandler(button);
// Applies a "blue" gradient to our Android navigation buttons
var gradientDrawable = new GradientDrawable();
gradientDrawable.SetOrientation(GradientDrawable.Orientation.TlBr);
gradientDrawable.SetColors(new int[] { Color.Argb(255, 20, 143, 194), Color.Argb(255, 0, 44, 119) });
gradientDrawable.SetGradientType(GradientType.RadialGradient);
gradientDrawable.SetGradientRadius(300);
gradientDrawable.SetGradientCenter(0.5f, 0);
button.SetBackgroundDrawable(gradientDrawable);
// Sets a small drop shadow to the buttons' text
button.SetShadowLayer(1, 1, 1, Color.Black);
}
}
protected override void OnElementChanged(ElementChangedEventArgs <Button> e)
{
base.OnElementChanged(e);
if (e.OldElement == null)
{
var button = Control;
// Applies a "gray" gradient to our Android popup buttons
var gradientDrawable = new GradientDrawable();
gradientDrawable.SetOrientation(GradientDrawable.Orientation.TlBr);
gradientDrawable.SetColors(new int[] { Color.Argb(255, 167, 169, 172), Color.Argb(255, 76, 76, 76) });
gradientDrawable.SetGradientType(GradientType.RadialGradient);
gradientDrawable.SetGradientRadius(300);
gradientDrawable.SetGradientCenter(0.5f, 0);
button.SetBackgroundDrawable(gradientDrawable);
// Sets a small drop shadow to the buttons' text
button.SetShadowLayer(1, 1, 1, Color.Black);
}
}