public static async Task <TResult> ShowModal <TViewController, TResult>(
UIViewController parentViewController,
TViewController viewController,
Action <TViewController, Action> dismissSubscriber = null,
UIModalPresentationStyle presentationStyle = UIModalPresentationStyle.FormSheet,
UIModalTransitionStyle transitionStyle = UIModalTransitionStyle.CoverVertical,
Action completionHandler = null,
Func <TViewController, TResult> resultGetter = null,
bool dismissOnTapOutside = true,
bool disposeOnFinish = false
) where TViewController : UIViewController
{
try {
if (completionHandler == null)
{
completionHandler = Tools.Lambda.NoOp;
}
if (dismissOnTapOutside && presentationStyle.IsIn(UIModalPresentationStyle.FullScreen, UIModalPresentationStyle.OverFullScreen))
{
dismissOnTapOutside = false;
}
if (dismissSubscriber == null && dismissOnTapOutside == false)
{
throw new ArgumentException("dismissSubscriber is null and dismissOnTapOutside is effectively false, this will result in an unclosable modal screen");
}
var signal = new ManualResetEventSlim();
viewController.ModalPresentationStyle = presentationStyle;
viewController.ModalTransitionStyle = transitionStyle;
Action dismissModalDialogAction = signal.Set;
dismissSubscriber(viewController, dismissModalDialogAction);
var currentPresentedController = parentViewController.FindPresentedViewController();
if (currentPresentedController != null)
{
parentViewController = currentPresentedController;
}
viewController.ProvidesPresentationContextTransitionStyle = true;
viewController.DefinesPresentationContext = true;
await parentViewController.PresentViewControllerAsync(viewController, true);
completionHandler();
var window = parentViewController.View.Window;
UITapGestureRecognizerEx tapOutsideGesture = null;
if (dismissOnTapOutside)
{
tapOutsideGesture = new UITapGestureRecognizerEx(async(x) => {
if (x.State == UIGestureRecognizerState.Ended)
{
var location = x.LocationInView(null);//Passing nil gives us coordinates in the window
if (!viewController.View.PointInside(viewController.View.ConvertPointFromView(location, window), null))
{
//Convert tap location into the local view's coordinate system. If outside, dismiss the view.
signal.Set();
}
}
});
tapOutsideGesture.NumberOfTapsRequired = 1;
tapOutsideGesture.CancelsTouchesInView = false;
window.AddGestureRecognizer(tapOutsideGesture);
}
await Task.Run(() => signal.Wait());
if (dismissOnTapOutside)
{
window.RemoveGestureRecognizer(tapOutsideGesture);
}
if (!viewController.IsBeingDismissed && parentViewController.ModalViewController == viewController)
{
await viewController.DismissViewControllerAsync(true);
}
return(resultGetter == null ? default(TResult) : resultGetter(viewController));
} finally {
if (disposeOnFinish)
{
viewController.Dispose();
}
}
}
