//https://stackoverflow.com/a/26569703/1981314
void HandleRecognizer(UIScreenEdgePanGestureRecognizer recognizer, UINavigationController navigationController)
{
var translate = recognizer.TranslationInView(recognizer.View);
var percent = translate.X / recognizer.View.Bounds.Width * 2;
var velocity = recognizer.VelocityInView(recognizer.View);
if (percent > 1)
{
percent = 1;
}
if (recognizer.State == UIGestureRecognizerState.Began)
{
interactor = new UIPercentDrivenInteractiveTransition();
navigationController.PopViewController(true);
}
else if (recognizer.State == UIGestureRecognizerState.Changed)
{
interactor.UpdateInteractiveTransition(percent);
}
else if (recognizer.State == UIGestureRecognizerState.Ended)
{
if (percent > 0.5 || velocity.X > 0)
{
interactor.FinishInteractiveTransition();
}
else
{
interactor.CancelInteractiveTransition();
}
interactor = null;
}
}
void InteractiveTransitionRecognizerAction(UIScreenEdgePanGestureRecognizer sender, IReadOnlyList <Page> pageStack)
{
var percent = sender.TranslationInView(sender.View).X / sender.View.Frame.Width;
var finishTransitionOnEnd = percent > 0.5 || sender.VelocityInView(sender.View).X > 300;
_renderer.EdgeGesturePanned(new EdgeGesturePannedArgs
{
State = sender.State,
Percent = percent,
FinishTransitionOnEnd = finishTransitionOnEnd
});
switch (sender.State)
{
case UIGestureRecognizerState.Began:
_renderer.PercentDrivenInteractiveTransition = new UIPercentDrivenInteractiveTransition();
((UINavigationController)_renderer).PopViewController(true);
break;
case UIGestureRecognizerState.Changed:
_renderer.PercentDrivenInteractiveTransition.UpdateInteractiveTransition(percent);
break;
case UIGestureRecognizerState.Cancelled:
case UIGestureRecognizerState.Failed:
_renderer.PercentDrivenInteractiveTransition.CancelInteractiveTransition();
_renderer.PercentDrivenInteractiveTransition = null;
break;
case UIGestureRecognizerState.Ended:
if (finishTransitionOnEnd)
{
_renderer.PercentDrivenInteractiveTransition.FinishInteractiveTransition();
/*
* IMPORTANT!
*
* at the end of this transition, we need to check if we want a normal pop gesture or the custom one for the new page
* as we said before, the custom pop gesture doesnt play well with "normal" pages.
* So, at the end of the transition, we check if a page exists before the one we are opening and then check the mapstack
* If the previous page of the pop destination doesnt have shared transitions, we remove our custom gesture
*/
var pageCount = pageStack.Count;
if (pageCount > 2 && _renderer.TransitionMap.GetMap(pageStack[pageCount - 3], null).Count == 0)
{
RemoveInteractiveTransitionRecognizer();
}
}
else
{
_renderer.PercentDrivenInteractiveTransition.CancelInteractiveTransition();
}
_renderer.PercentDrivenInteractiveTransition = null;
break;
}
}