private static void PrepareSharedTransition(ITransitionMapper tm, Page pageFrom, Page pageTo, bool isPop)
{
IReadOnlyList <TransitionDetail> transFrom = null;
if (isPop)
{
// current page is pageFrom being popped; new page will be pageTo
transFrom = tm.GetMap(pageFrom, null, isPop);
}
else
{
// current page == pageFrom; new page to push pageTo
// group is used when pushing from a page with the group defined
var group = (string)pageFrom?.GetValue(SharedTransitionNavigationPage.TransitionSelectedGroupProperty);
transFrom = tm.GetMap(pageFrom, group, isPop);
}
// save this so that when we return to the page, we don't have to guess which items to use
pageFrom?.SetValue(SharedTransitionNavigationPage.TransitionFromMapProperty, transFrom);
var cas = ConnectedAnimationService.GetForCurrentView();
if (pageFrom != null)
{
cas.DefaultDuration = TimeSpan.FromMilliseconds((long)pageFrom.GetValue(SharedTransitionNavigationPage.TransitionDurationProperty));
}
// TODO: better indication of Background items to do first...
foreach (var bg in transFrom.Where(td => td.TransitionName.Contains("Background")))
{
if (bg.NativeView.IsAlive)
{
var ca = cas.PrepareToAnimate(bg.TransitionName, (UIElement)bg.NativeView.Target);
}
}
foreach (var detail in transFrom.Where(td => !td.TransitionName.Contains("Background")))
{
if (detail.NativeView.IsAlive)
{
var ca = cas.PrepareToAnimate(detail.TransitionName, (UIElement)detail.NativeView.Target);
}
}
}
private static void ExecutePreparedTransition(ITransitionMapper tm, Page pageFrom, Page pageTo, bool isPop)
{
var cas = ConnectedAnimationService.GetForCurrentView();
var transFrom = (IReadOnlyList <TransitionDetail>)pageFrom?.GetValue(SharedTransitionNavigationPage.TransitionFromMapProperty);
pageFrom?.SetValue(SharedTransitionNavigationPage.TransitionFromMapProperty, null);
// group is used when popping back to a page with the group defined
var group = (string)pageTo?.GetValue(SharedTransitionNavigationPage.TransitionSelectedGroupProperty);
var transTo = tm.GetMap(pageTo, group, !isPop);
foreach (var detail in transTo)
{
ConnectedAnimation animation = cas.GetAnimation(detail.TransitionName);
if (animation != null)
{
if (detail.NativeView.IsAlive)
{
if (detail.View.Height == -1)
{
// need to capture the value and then use that in the event handler since it changes with each time through the loop
var acapture = animation;
detail.View.SizeChanged += (s, e) =>
{
// save this so we only call TryStart on the first time through
var atemp = acapture;
acapture = null;
if (atemp != null && detail.NativeView.IsAlive)
{
atemp.TryStart((UIElement)detail.NativeView.Target);
}
};
}
else
{
var b = animation.TryStart((UIElement)detail.NativeView.Target);
}
}
}
}
foreach (var transChk in transFrom ?? Enumerable.Empty <TransitionDetail>())
{
if (!transTo.Any(t => t.TransitionName == transChk.TransitionName))
{
// transFrom item not in transTo
ConnectedAnimation animation = cas.GetAnimation(transChk.TransitionName);
if (animation != null)
{
animation.Cancel();
}
if (isPop)
{
// TODO: figure out why this is needed
transChk.View.IsVisible = false;
if (transChk.NativeView.IsAlive)
{
((UIElement)transChk.NativeView.Target).Visibility = Visibility.Collapsed;
}
}
}
}
}