Fix crash in Chat sample and make it work correctly (#365)

* Fix crash in Chat sample and make it work correctly

* Update Chat/Chat/ChatViewController.cs

---------

Co-authored-by: Martin Loebger <extmloebger@gnresound.com>
Co-authored-by: Manuel de la Pena <mandel@microsoft.com>
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>

Author: 4 people

Chat/Chat/ChatViewController.cs

@@ -19,7 +19,6 @@ public class ChatViewController : UIViewController {
 
 		NSLayoutConstraint toolbarBottomConstraint;
 		NSLayoutConstraint toolbarHeightConstraint;
-		int notifCount = 0;
 
 		ChatInputView chatInputView;
 
@@ -142,9 +141,10 @@ void SetUpToolbar ()
 
 			if (UIDevice.CurrentDevice.CheckSystemVersion (11, 0)) {   // iPhone X layout
 				var safeGuide = View.SafeAreaLayoutGuide;
-				toolbar.HeightAnchor.ConstraintEqualTo (44).Active = true;
 				toolbar.LeadingAnchor.ConstraintEqualTo (safeGuide.LeadingAnchor).Active = true;
 				toolbar.TrailingAnchor.ConstraintEqualTo (safeGuide.TrailingAnchor).Active = true;
+				toolbarHeightConstraint = toolbar.HeightAnchor.ConstraintEqualTo (44);
+				toolbarHeightConstraint.Active = true;
 				toolbarBottomConstraint = toolbar.BottomAnchor.ConstraintEqualTo (safeGuide.BottomAnchor);
 				toolbarBottomConstraint.Active = true;
 			} else {
@@ -228,33 +228,18 @@ void AdjustInputToolbar (nfloat change)
 
 		void KeyboardWillShowHandler (object sender, UIKeyboardEventArgs e)
 		{
-			UpdateButtomLayoutConstraint (e);
+			if (UIDevice.CurrentDevice.CheckSystemVersion (11, 0)) {   // iPhone X layout
+				SetToolbarContstraint (-e.FrameEnd.Height);
+			} else {
+				SetToolbarContstraint (e.FrameEnd.Height);
+			}
 		}
 
 		void KeyboardWillHideHandler (object sender, UIKeyboardEventArgs e)
 		{
-			notifCount = 0;
 			SetToolbarContstraint (0);
 		}
 
-		void UpdateButtomLayoutConstraint (UIKeyboardEventArgs e)
-		{
-			UIViewAnimationCurve curve = e.AnimationCurve;
-			if (UIDevice.CurrentDevice.CheckSystemVersion (11, 0)) {
-				UIView.Animate (e.AnimationDuration, 0, ConvertToAnimationOptions (e.AnimationCurve), () => {
-					nfloat offsetFromBottom = toolbar.Frame.GetMaxY () - e.FrameEnd.GetMinY ();
-					offsetFromBottom = NMath.Max (0, offsetFromBottom);
-					if (++notifCount >= 2) { SetToolbarContstraint (-offsetFromBottom); }
-				}, null);
-			} else {
-				UIView.Animate (e.AnimationDuration, 0, ConvertToAnimationOptions (e.AnimationCurve), () => {
-					nfloat offsetFromBottom = tableView.Frame.GetMaxY () - e.FrameEnd.GetMinY ();
-					offsetFromBottom = NMath.Max (0, offsetFromBottom);
-					SetToolbarContstraint (offsetFromBottom);
-				}, null);
-			}
-		}
-
 		void SetToolbarContstraint (nfloat constant)
 		{
 			toolbarBottomConstraint.Constant = constant;