private void OnActivityListLoaded(object sender, RoutedEventArgs e)
{
_scrollViewer = ActivityList.GetVisualDescendents <ScrollViewer>().FirstOrDefault();
if (_scrollViewer != null)
{
_scrollViewer.ViewChanged += OnScrollViewerViewChanged;
_scrollViewer.ViewChanging += OnScrollViewerViewChanging;
_scrollViewer.IsScrollInertiaEnabled = true;
}
}
private void OnActivityListLoaded(object sender, RoutedEventArgs e)
{
_scrollViewer = ActivityList.GetVisualDescendents <ScrollViewer>().FirstOrDefault();
if (_scrollViewer != null)
{
_scrollViewer.ViewChanged += OnScrollViewerViewChanged;
_scrollViewer.ViewChanging += OnScrollViewerViewChanging;
_scrollViewer.IsScrollInertiaEnabled = true;
_scrollViewer.DirectManipulationStarted += OnDirectManipStarted;
_scrollViewer.DirectManipulationCompleted += OnDirectManipCompleted;
#region PullToRefresh Animation Setup
// Retrieve the ScrollViewer manipulation and the Compositor.
_scrollerViewerManipulation = ElementCompositionPreview.GetScrollViewerManipulationPropertySet(_scrollViewer);
//Compositor = _scrollerViewerManipulation.Compositor;
// Create a rotation expression animation based on the overpan distance of the ScrollViewer.
_rotationAnimation = Compositor.CreateExpressionAnimation();
_rotationAnimation.SetScalarParameter("MyMultiplier", 10.0f);
_rotationAnimation.SetScalarParameter("MyMaxDegree", 400.0f);
_rotationAnimation.SetReferenceParameter("MyScrollManipulation", _scrollerViewerManipulation);
_rotationAnimation.Expression = "min(max(0, MyScrollManipulation.Translation.Y) * MyMultiplier, MyMaxDegree)";
// Create an opacity expression animation based on the overpan distance of the ScrollViewer.
_opacityAnimation = Compositor.CreateExpressionAnimation();
_opacityAnimation.SetScalarParameter("MyDivider", 30.0f);
_opacityAnimation.SetReferenceParameter("MyScrollManipulation", _scrollerViewerManipulation);
_opacityAnimation.Expression = "min(max(0, MyScrollManipulation.Translation.Y) / MyDivider, 1)";
// Create an offset expression animation based on the overpan distance of the ScrollViewer.
_offsetAnimation = Compositor.CreateExpressionAnimation();
_offsetAnimation.SetScalarParameter("MyDivider", 30.0f);
_offsetAnimation.SetScalarParameter("MyMaxOffsetY", REFRESH_ICON_MAX_OFFSET_Y);
_offsetAnimation.SetReferenceParameter("MyScrollManipulation", _scrollerViewerManipulation);
_offsetAnimation.Expression = "(min(max(0, MyScrollManipulation.Translation.Y) / MyDivider, 1)) * MyMaxOffsetY";
// Create a keyframe animation to reset properties like Offset.Y, Opacity, etc.
_resetAnimation = Compositor.CreateScalarKeyFrameAnimation();
_resetAnimation.InsertKeyFrame(1.0f, 0.0f);
// Create a loading keyframe animation (in this case, a rotation animation).
_loadingAnimation = Compositor.CreateScalarKeyFrameAnimation();
_loadingAnimation.InsertKeyFrame(1.0f, 360);
_loadingAnimation.Duration = TimeSpan.FromMilliseconds(800);
_loadingAnimation.IterationBehavior = AnimationIterationBehavior.Forever;
// Get the RefreshIcon's Visual.
_refreshIconVisual = ElementCompositionPreview.GetElementVisual(RefreshIcon);
// Set the center point for the rotation animation.
_refreshIconVisual.CenterPoint = new Vector3(Convert.ToSingle(RefreshIcon.ActualWidth / 2), Convert.ToSingle(RefreshIcon.ActualHeight / 2), 0);
// Get the ListView's inner Border's Visual.
var border = (Border)VisualTreeHelper.GetChild(ActivityList, 0);
_borderVisual = ElementCompositionPreview.GetElementVisual(border);
_refreshIconVisual.StartAnimation(nameof(_refreshIconVisual.RotationAngleInDegrees), _rotationAnimation);
_refreshIconVisual.StartAnimation(nameof(_refreshIconVisual.Opacity), _opacityAnimation);
_refreshIconVisual.StartAnimation($"{nameof(_refreshIconVisual.Offset)}.{nameof(_refreshIconVisual.Offset.Y)}", _offsetAnimation);
_borderVisual.StartAnimation($"{nameof(_borderVisual.Offset)}.{nameof(_borderVisual.Offset.Y)}", _offsetAnimation);
#endregion
}
}
