/// <summary>
/// <see cref="T:Xamarin.Forms.Platform.iOS.PageRenderer"/> override that is called whenever the associated
/// <see cref="T:Xamarin.Forms.ContentPage"/> instance changes
/// </summary>
/// <param name="e"><see cref="T:Xamarin.Forms.Platform.iOS.VisualElementChangedEventArgs"/> that specifies the
/// previously and newly assigned <see cref="T:Xamarin.Forms.ContentPage"/> instances
/// </param>
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
e.OldElement.PropertyChanging -= OnElementPropertyChanging;
e.OldElement.PropertyChanged -= OnElementPropertyChanged;
Gradient bkgrndGradient = ContentPageGloss.GetBackgroundGradient(e.OldElement);
if (bkgrndGradient != null)
{
bkgrndGradient.DetachRenderer(this);
}
}
if (e.NewElement != null)
{
e.NewElement.PropertyChanging += OnElementPropertyChanging;
e.NewElement.PropertyChanged += OnElementPropertyChanged;
Gradient bkgrndGradient = ContentPageGloss.GetBackgroundGradient(Element);
if (bkgrndGradient != null)
{
bkgrndGradient.AttachRenderer(ContentPageGloss.BackgroundGradientProperty.PropertyName,
this);
}
}
}
/// <summary>
/// Private event handler that is called whenever a <see cref="T:Xamarin.Forms.BindableObject.PropertyChanging"/>
/// event is fired.
/// </summary>
/// <param name="sender">Sender.</param>
/// <param name="args">Property changing event arguments</param>
void OnElementPropertyChanging(object sender, Xamarin.Forms.PropertyChangingEventArgs args)
{
if (args.PropertyName == ContentPageGloss.BackgroundGradientProperty.PropertyName)
{
Gradient bkgrndGradient = ContentPageGloss.GetBackgroundGradient(Element);
if (bkgrndGradient != null)
{
bkgrndGradient.DetachRenderer(this);
}
}
}
/// <summary>
/// Dispose any created resources and prepare the instance for garbage collection
/// </summary>
/// <param name="disposing">If set to <c>true</c>, dispose any created resources</param>
protected override void Dispose(bool disposing)
{
if (disposing)
{
Gradient bkgrndGradient = ContentPageGloss.GetBackgroundGradient(Element);
if (bkgrndGradient != null)
{
bkgrndGradient.DetachRenderer(this);
}
}
base.Dispose(disposing);
}
