LottieXamarin: Bug: InitAnimationViewForElement throws: ArgumentNullException (Value cannot be null.)

Steps to reproduce 📜

1. Run SimpleAppIntro sample project on iOS or Android and start the animated app intro: https://github.com/galadril/Xam.Plugin.SimpleAppIntro
2. I now show the lottie animation within a carouselview… moving between view via gestures has no issue. But as soon as i use a next button (that sets the currentPosition in the viewmodel) i get a crash on the lottie animation (see crash details below)
3. The lottie view has a binding for the Animation, and I’m sure that all animations have a valid json file (all animations are correctly loaded via gestures)

Expected behavior 🤔

The animation should show up

Actual behavior 🐛

I get an exception on the Init of AnimationViewRenderer.InitAnimationViewForElement: System.ArgumentNullException: Value cannot be null. Parameter name: path

Configuration 🔧

Version: 2.5.4

Platform:

• 📱 iOS
• 🤖 Android
• 🏁 WPF
• 🌎 UWP
• 🍎 MacOS
• 📺 tvOS
• 🐒 Xamarin.Forms

Tested via Xamarin forms build to Android and iOS

Crash report

**Unhandled Exception:**
System.ArgumentNullException: Value cannot be null.
Parameter name: path
  at Foundation.NSUrl..ctor (System.String path, System.Boolean isDir) [0x0000e] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/Foundation/NSUrl.g.cs:112 
  at Foundation.NSUrl.FromFilename (System.String url) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/Foundation/NSUrl.cs:85 
  at Lottie.Forms.iOS.Renderers.AnimationViewRenderer.InitAnimationViewForElement (Lottie.Forms.AnimationView theElement) [0x00000] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/Platforms/Ios/AnimationViewRenderer.cs:113 
  at Lottie.Forms.iOS.Renderers.AnimationViewRenderer.OnElementPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00047] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/Platforms/Ios/AnimationViewRen
derer.cs:89 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:150 
  at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:398 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00114] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:623 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\
Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0003d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:573 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:99 
  at Lottie.Forms.AnimationView.set_Animation (System.String value) [0x00000] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/AnimationView.cs:55 
  at Xam.Plugin.SimpleAppIntro.Views.AnimatedSlideView.OnIconSelected (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00001] in C:\intro\Xam.Plugin.SimpleAppIntro\Views\AnimatedSlideView.xaml.cs:28 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Xamarin.Forms.BindableObject.OnPropertyChanged (Syste
m.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:150 
  at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:398 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00114] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:623 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean
 fromTarget) [0x00216] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:173 
  at Xamarin.Forms.BindingExpression.Apply (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property) [0x0006b] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:78 
  at Xamarin.Forms.Binding.Apply (System.Object newContext, Xamarin.Forms.BindableObject bindObj, Xamarin.Forms.BindableProperty targetProperty, System.Boolean fromBindingContextChanged) [0x00057] in D:\a\1\s\Xamarin.Forms.Core\Binding.cs:131 
  at Xamarin.Forms.BindableObject.ApplyBindings (System.Boolean skipBindingContext, System.Boolean fromBindingContextChanged) [0x0003c] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:448 
  at Xamarin.Forms.BindableObject.SetInheritedBindingContext (Xamarin.Forms.BindableObject bindable, System.Object value) [0x0005a] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:135 
  at Xamarin.Forms.Element.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object conte
xt) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:532 
  at Xamarin.Forms.Element.OnBindingContextChanged () [0x00021] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:352 
  at Xamarin.Forms.View.OnBindingContextChanged () [0x00042] in D:\a\1\s\Xamarin.Forms.Core\View.cs:150 
  at Xamarin.Forms.BindableObject.SetInheritedBindingContext (Xamarin.Forms.BindableObject bindable, System.Object value) [0x00062] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:136 
  at Xamarin.Forms.Element.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object context) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:532 
  at Xamarin.Forms.TemplatedView.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object context) [0x00008] in D:\a\1\s\Xamarin.Forms.Core\TemplatedView.cs:65 
  at Xamarin.Forms.Element.OnBindingContextChanged () [0x00021] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:352 
  at Xamarin.Forms.View.OnBindingContextChanged () [0x00042] in D:\a\1\s\Xamarin.Forms.Core\View.cs:1
50 
  at Xamarin.Forms.ContentView.OnBindingContextChanged () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\ContentView.cs:16 
  at Xamarin.Forms.BindableObject.BindingContextPropertyChanged (Xamarin.Forms.BindableObject bindable, System.Object oldvalue, System.Object newvalue) [0x0000f] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:468 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:625 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindableObject.SetValue (Xama
rin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0003d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:573 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:99 
  at Xamarin.Forms.BindableObject.set_BindingContext (System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:25 
  at PanCardView.CardsView.CleanView (Xamarin.Forms.View view) [0x0001b] in <20a969e797574362a007100645ed2545>:0 
  at PanCardView.CardsView.EndAutoNavigation (Xamarin.Forms.View oldView, Xamarin.Forms.View newView, System.Guid animationId, PanCardView.Enums.AnimationDirection animationDirection) [0x00028] in <20a969e797574362a007100645ed2545>:0 
  at PanCardView.CardsView+<TryAutoNavigate>d__197.MoveNext () [0x001c5] in <20a969e797574362a007100645ed2545>:0 
--- End of stack trace from previous location where exception was thrown ---
 
 at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00037] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187 
  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156 
  at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128 
  at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/
class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357 
  at PanCardView.CardsView+<SetCurrentView>d__194.MoveNext () [0x0007d] in <20a969e797574362a007100645ed2545>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018 
  at Foundation.NSAsyncSynchronizationContextDispatcher.Apply () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/Foundation/NSAction.cs:178 
--- End of stack trace from previous location where exception was thrown ---
  at (wrapper managed-to-native) UIKit.UIApplication.UIApplicationMain(int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate
) [0x00005] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/UIKit/UIApplication.cs:79 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0002c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/UIKit/UIApplication.cs:63 
  at Xam.Plugin.SimpleAppIntro.iOS.Application.Main (System.String[] args) [0x00001] in C:\intro\Samples\Xam.Plugin.SimpleAppIntro.Samples\Xam.Plugin.SimpleAppIntro.Samples.iOS\Main.cs:17 
2018-08-17 02:18:16.481 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] Unhandled managed exception:
Value cannot be null.
Parameter name: path (System.ArgumentNullException)
  at Foundation.NSUrl..ctor (System.String path, System.Boolean isDir) [0x0000e] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/Foundation/NSUrl.g.cs:112 
  at Foundation.NSUrl.FromFilename (System.String url) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versi
ons/11.14.0.11/src/Xamarin.iOS/Foundation/NSUrl.cs:85 
  at Lottie.Forms.iOS.Renderers.AnimationViewRenderer.InitAnimationViewForElement (Lottie.Forms.AnimationView theElement) [0x00000] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/Platforms/Ios/AnimationViewRenderer.cs:113 
  at Lottie.Forms.iOS.Renderers.AnimationViewRenderer.OnElementPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00047] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/Platforms/Ios/AnimationViewRenderer.cs:89 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:150 
  at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:398 
  at Xamarin.Forms.BindableObject.SetValu
eActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00114] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:623 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0003d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:573 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:99 
  at Lottie.Forms.AnimationView.se
t_Animation (System.String value) [0x00000] in /Users/martijn/Documents/OpenSource/LottieXamarin/Lottie.Forms/AnimationView.cs:55 
  at Xam.Plugin.SimpleAppIntro.Views.AnimatedSlideView.OnIconSelected (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00001] in C:\intro\Xam.Plugin.SimpleAppIntro\Views\AnimatedSlideView.xaml.cs:28 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:150 
  at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:398 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attri
butes, System.Boolean silent) [0x00114] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:623 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x00216] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:173 
  at Xamarin.Forms.BindingExpression.Apply (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property) [0x0006b] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:78 
  at Xamarin.Forms.Binding.Apply (System.Object newContext, Xamarin.Forms.BindableObject bindObj, Xamarin.Forms.BindableProperty targetProperty, System.Boolean fromBindingCo
ntextChanged) [0x00057] in D:\a\1\s\Xamarin.Forms.Core\Binding.cs:131 
  at Xamarin.Forms.BindableObject.ApplyBindings (System.Boolean skipBindingContext, System.Boolean fromBindingContextChanged) [0x0003c] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:448 
  at Xamarin.Forms.BindableObject.SetInheritedBindingContext (Xamarin.Forms.BindableObject bindable, System.Object value) [0x0005a] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:135 
  at Xamarin.Forms.Element.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object context) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:532 
  at Xamarin.Forms.Element.OnBindingContextChanged () [0x00021] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:352 
  at Xamarin.Forms.View.OnBindingContextChanged () [0x00042] in D:\a\1\s\Xamarin.Forms.Core\View.cs:150 
  at Xamarin.Forms.BindableObject.SetInheritedBindingContext (Xamarin.Forms.BindableObject bindable, System.Object value) [0x00062] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:136 
  at X
amarin.Forms.Element.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object context) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:532 
  at Xamarin.Forms.TemplatedView.SetChildInheritedBindingContext (Xamarin.Forms.Element child, System.Object context) [0x00008] in D:\a\1\s\Xamarin.Forms.Core\TemplatedView.cs:65 
  at Xamarin.Forms.Element.OnBindingContextChanged () [0x00021] in D:\a\1\s\Xamarin.Forms.Core\Element.cs:352 
  at Xamarin.Forms.View.OnBindingContextChanged () [0x00042] in D:\a\1\s\Xamarin.Forms.Core\View.cs:150 
  at Xamarin.Forms.ContentView.OnBindingContextChanged () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\ContentView.cs:16 
  at Xamarin.Forms.BindableObject.BindingContextPropertyChanged (Xamarin.Forms.BindableObject bindable, System.Object oldvalue, System.Object newvalue) [0x0000f] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:468 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePro
pertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:625 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0015b] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:417 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0003d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:573 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:99 
  at Xamarin.Forms.BindableObject.set_BindingContext (System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Bindable
Object.cs:25 
  at PanCardView.CardsView.CleanView (Xamarin.Forms.View view) [0x0001b] in <20a969e797574362a007100645ed2545>:0 
  at PanCardView.CardsView.EndAutoNavigation (Xamarin.Forms.View oldView, Xamarin.Forms.View newView, System.Guid animationId, PanCardView.Enums.AnimationDirection animationDirection) [0x00028] in <20a969e797574362a007100645ed2545>:0 
  at PanCardView.CardsView+<TryAutoNavigate>d__197.MoveNext () [0x001c5] in <20a969e797574362a007100645ed2545>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00037] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187 
  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in /Library/Frameworks/Xamarin.iOS.framework/Versions/1
1.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156 
  at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128 
  at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357 
  at PanCardView.CardsView+<SetCurrentView>d__194.MoveNext () [0x0007d] in <20a969e797574362a007100645ed2545>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/
mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018 
  at Foundation.NSAsyncSynchronizationContextDispatcher.Apply () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/Foundation/NSAction.cs:178 
--- End of stack trace from previous location where exception was thrown ---
  at (wrapper managed-to-native) UIKit.UIApplication.UIApplicationMain(int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate) [0x00005] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/UIKit/UIApplication.cs:79 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0002c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.14.0.11/src/Xamarin.iOS/UIKit/UIApplication.cs:63 
  at Xam.Plugin.SimpleAppIntro.iOS.Application.Main (System.String[] args) [0x00001] in C:\intro\Samples\Xam.Pl
ugin.SimpleAppIntro.Samples\Xam.Plugin.SimpleAppIntro.Samples.iOS\Main.cs:17 
2018-08-17 02:18:16.482 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: Stacktrace:

2018-08-17 02:18:16.482 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 
Native stacktrace:

2018-08-17 02:18:16.484 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	0   Xam.Plugin.SimpleAppIntro.iOS       0x00000001033fdeb4 mono_handle_native_crash + 244
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	1   libsystem_platform.dylib            0x00000001143e4f5a _sigtramp + 26
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	2   libsystem_pthread.dylib             0x000000011440330b _pthread_keys + 9723
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	3   libsystem_c.dylib                   0x000000011401ac97 abort + 127
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	4   Xam.Plugin.SimpleAppIntro.iO
S       0x00000001035ee07f xamarin_unhandled_exception_handler + 47
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	5   Xam.Plugin.SimpleAppIntro.iOS       0x000000010349520e mono_invoke_unhandled_exception_hook + 158
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	6   Xam.Plugin.SimpleAppIntro.iOS       0x00000001033fda80 mono_handle_exception_internal + 6240
2018-08-17 02:18:16.485 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	7   Xam.Plugin.SimpleAppIntro.iOS       0x00000001033fc219 mono_handle_exception + 25
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	8   Xam.Plugin.SimpleAppIntro.iOS       0x000000010337d533 mono_amd64_throw_exception + 131
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	9   ???                                 0x000000012e6225a7 0x0 + 5073151399
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	10  Xam.Plugin.Si
mpleAppIntro.iOS       0x00000001032dbe9c _ZL31native_to_managed_trampoline_20P11objc_objectP13objc_selectorPP11_MonoMethodj + 284
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	11  Xam.Plugin.SimpleAppIntro.iOS       0x00000001032e0434 -[__MonoMac_NSAsyncSynchronizationContextDispatcher xamarinApplySelector] + 52
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	12  Foundation                          0x000000010e752d5e __NSThreadPerformPerform + 330
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	13  CoreFoundation                      0x0000000111f63bb1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
2018-08-17 02:18:16.486 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	14  CoreFoundation                      0x0000000111f484af __CFRunLoopDoSources0 + 271
2018-08-17 02:18:16.487 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	15  CoreFoundation                      0x00000001
11f47a6f __CFRunLoopRun + 1263
2018-08-17 02:18:16.487 Xam.Plugin.SimpleAppIntro.iOS[37838:10565884] critical: 	16  CoreFoundation