private async void StartGradientAnimation()
{
_cancellationTokenSource = new CancellationTokenSource();
var gradientStates = new List <(Color, Color)>
{
(Color.FromHex("#4A148C"), Color.FromHex("#D500F9")),
(Color.FromHex("#FF6F00"), Color.FromHex("#FFC400")),
(Color.FromHex("#1B5E20"), Color.FromHex("#00E676")),
(Color.FromHex("#B71C1C"), Color.FromHex("#FF1744"))
};
var state = 0;
while (!_cancellationTokenSource.Token.IsCancellationRequested)
{
var fromColorStart = gradientStates[state].Item1;
var fromColorEnd = gradientStates[state].Item2;
var nextState = state + 1 > 3 ? 0 : state + 1;
var toColorStart = gradientStates[nextState].Item1;
var toColorEnd = gradientStates[nextState].Item2;
var taskCompletionSource = new TaskCompletionSource <bool>();
new Animation
{
{
0, 1, new Animation(d =>
{
BackgroundEffect.GetBackground(BackgroundView).GradientBrush.Gradients =
new List <GradientStop>
{
new GradientStop(GetColor(d, fromColorStart, toColorStart), 0),
new GradientStop(GetColor(d, fromColorEnd, toColorEnd), 1)
};
})
}
}.Commit(BackgroundView, "name", 16, 4000, Easing.Linear,
(d, b) => taskCompletionSource.TrySetResult(true));
await taskCompletionSource.Task;
if (_cancellationTokenSource.Token.IsCancellationRequested)
{
break;
}
state++;
if (state > 3)
{
state = 0;
}
}
}
private void SetVisualElement(VisualElement oldElement, VisualElement newElement)
{
if (oldElement != null)
{
_context = null;
_nativeView = null;
oldElement.PropertyChanged -= OnElementPropertyChanged;
}
if (newElement != null)
{
ResolveNativeView();
_context = _nativeView.Context;
newElement.PropertyChanged += OnElementPropertyChanged;
}
IMaterialVisualElement oldMaterialVisualElement;
IMaterialVisualElement newMaterialVisualElement;
switch (oldElement)
{
case IBackgroundElement oldBackgroundElement:
oldMaterialVisualElement = oldBackgroundElement.Background;
break;
case IMaterialVisualElement oldMaterialElement:
oldMaterialVisualElement = oldMaterialElement;
break;
default:
oldMaterialVisualElement = oldElement == null ? null : BackgroundEffect.GetBackground(oldElement);
break;
}
switch (newElement)
{
case IBackgroundElement newBackgroundElement:
newMaterialVisualElement = newBackgroundElement.Background;
break;
case IMaterialVisualElement newMaterialElement:
newMaterialVisualElement = newMaterialElement;
break;
default:
newMaterialVisualElement = newElement == null ? null : BackgroundEffect.GetBackground(newElement);
break;
}
_visualElement = newElement;
SetBackgroundElement(oldMaterialVisualElement, newMaterialVisualElement);
}
private static IMaterialVisualElement GetMaterialVisualElement(VisualElement element)
{
switch (element)
{
case IBackgroundElement oldBackgroundElement:
return(oldBackgroundElement.Background);
case IMaterialVisualElement oldMaterialElement:
return(oldMaterialElement);
default:
return(element == null ? null : BackgroundEffect.GetBackground(element));
}
}
private void SetVisualElement(VisualElement oldElement, VisualElement newElement)
{
if (oldElement != null)
{
oldElement.PropertyChanged -= OnElementPropertyChanged;
}
if (newElement != null)
{
newElement.PropertyChanged += OnElementPropertyChanged;
}
IMaterialVisualElement oldMaterialVisualElement;
IMaterialVisualElement newMaterialVisualElement;
switch (oldElement)
{
case IBackgroundElement oldBackgroundElement:
oldMaterialVisualElement = oldBackgroundElement.Background;
break;
case IMaterialVisualElement oldMaterialElement:
oldMaterialVisualElement = oldMaterialElement;
break;
default:
oldMaterialVisualElement = oldElement == null ? null : BackgroundEffect.GetBackground(oldElement);
break;
}
switch (newElement)
{
case IBackgroundElement newBackgroundElement:
newMaterialVisualElement = newBackgroundElement.Background;
break;
case IMaterialVisualElement newMaterialElement:
newMaterialVisualElement = newMaterialElement;
break;
default:
newMaterialVisualElement = newElement == null ? null : BackgroundEffect.GetBackground(newElement);
break;
}
_visualElement = newElement;
SetBackgroundElement(oldMaterialVisualElement, newMaterialVisualElement);
}