The map is displayed properly with pins etc. However under iOS I'm receiving this error when switching to a different view, even without pins etc. Maybe a configuration issue in Info.plist?
System.NullReferenceException: Object reference not set to an instance of an object
at Xamarin.Forms.GoogleMaps.iOS.MapRenderer.OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) [0x00069] in <0bdc53fe1bce4b6e878e432cac02c7af>:0
at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].SetElement (TElement element) [0x00110] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.iOS\VisualElementRenderer.cs:167
at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].Dispose (System.Boolean disposing) [0x0007b] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.iOS\VisualElementRenderer.cs:218
at Xamarin.Forms.Platform.iOS.ViewRenderer`2[TView,TNativeView].Dispose (System.Boolean disposing) [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.iOS\ViewRenderer.cs:42
at Xamarin.Forms.GoogleMaps.iOS.MapRenderer.Dispose (System.Boolean disposing) [0x000a8] in <0bdc53fe1bce4b6e878e432cac02c7af>:0
at Foundation.NSObject.Dispose () [0x00000] in /Users/builder/data/lanes/4292/e66c6f19/source/xamarin-macios/src/Foundation/NSObject2.cs:133
at Xamarin.Forms.Platform.iOS.Platform.DisposeModelAndChildrenRenderers (Xamarin.Forms.Element view) [0x00038] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.iOS\Platform.cs:231
at Xamarin.Forms.Platform.iOS.Platform.HandleChildRemoved (System.Object sender, Xamarin.Forms.ElementEventArgs e) [0x00007] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.iOS\Platform.cs:342
at Xamarin.Forms.Element.OnDescendantRemoved (Xamarin.Forms.Element child) [0x00008] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Element.cs:601
at Xamarin.Forms.Element.OnDescendantRemoved (Xamarin.Forms.Element child) [0x00022] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Element.cs:604
I had similar issue but once i updated xamarin.Forms.googlemaps to this version
https://www.nuget.org/packages/Xamarin.Forms.GoogleMaps/1.8.1
Related
I have tried a lot of combination to test the code in LoadData function.
The first time the Page loaded, the LoadData function got called. Later user change the date which causing the LoadData function to be called again. This time there was an error quoted below. If I commented the Collection = programs line, the code have no problem.
The problem even if the programs has 0 item in the second execution of the function.
public async Task LoadData (DateTime day)
{
this.day = day;
var programs = await new ECEProgramLogic().GetGrouppedProgram(day.Date, actionNameType);
Collection = programs;
}
private ObservableCollection<GroupViewModel<object>> collection;
public ObservableCollection<GroupViewModel<object>> Collection
{
get
{
return collection;
}
set
{
collection = value;
Banner = new NoDataBannerViewModel<GroupViewModel<object>>(value, AppResources.NoDataToShow);
OnPropertyChanged(nameof(Collection));
}
}
Specified argument was out of the range of valid values. Parameter
name: index
Stacktrace from Xamarin:
at Xamarin.Forms.ListProxy.get_Item (System.Int32 index) [0x0000b] in D:\agent_work\1\s\Xamarin.Forms.Core\ListProxy.cs:127
at Xamarin.Forms.ListProxy.System.Collections.IList.get_Item (System.Int32 index) [0x00000] in D:\agent_work\1\s\Xamarin.Forms.Core\ListProxy.cs:444
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].get_Item (System.Int32 index) [0x00008] in <afec569c85894ae9a18371a2fecd2d37>:0
at Xamarin.Forms.Platform.iOS.ListViewRenderer+ListViewDataSource.HeaderViewDisplayingEnded (UIKit.UITableView tableView, UIKit.UIView headerView, System.nint section) [0x0001f] in <82f6100a289642ae988dc0d85a373bef>:0
at (wrapper managed-to-native) ObjCRuntime.Messaging.void_objc_msgSend(intptr,intptr)
at UIKit.UITableView.ReloadData () [0x00008] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.9.1.24/src/Xamarin.iOS/UIKit/UITableView.g.cs:792
at Xamarin.Forms.Platform.iOS.ListViewRenderer.UpdateItems (System.Collections.Specialized.NotifyCollectionChangedEventArgs e, System.Int32 section, System.Boolean resetWhenGrouped) [0x002b8] in <82f6100a289642ae988dc0d85a373bef>:0
at Xamarin.Forms.Platform.iOS.ListViewRenderer.OnCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00000] in <82f6100a289642ae988dc0d85a373bef>:0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].OnCollectionChanged (System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x0000a] in :0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].GroupedReset () [0x000b6] in <afec569c85894ae9a18371a2fecd2d37>:0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].OnCollectionChangedGrouped (System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00459] in :0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].OnProxyCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e, System.Boolean fixWindows) [0x00008] in <afec569c85894ae9a18371a2fecd2d37>:0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].OnProxyCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00000] in :0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].OnItemsSourceChanged (System.Boolean fromGrouping) [0x00069] in <afec569c85894ae9a18371a2fecd2d37>:0
at Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].BindableOnPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00020] in :0
at (wrapper delegate-invoke) .invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x0000a] in D:\agent_work\1\s\Xamarin.Forms.Core\BindableObject.cs:146
at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in D:\agent_work\1\s\Xamarin.Forms.Core\Element.cs:401
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) [0x00107] in D:\agent_work\1\s\Xamarin.Forms.Core\BindableObject.cs:602
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:\agent_work\1\s\Xamarin.Forms.Core\BindableObject.cs:399
at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x001f9] in D:\agent_work\1\s\Xamarin.Forms.Core\BindingExpression.cs:172
at Xamarin.Forms.BindingExpression.Apply (System.Boolean fromTarget) [0x0003e] in D:\agent_work\1\s\Xamarin.Forms.Core\BindingExpression.cs:56
at Xamarin.Forms.BindingExpression+BindingExpressionPart.b__47_0 () [0x00000] in D:\agent_work\1\s\Xamarin.Forms.Core\BindingExpression.cs:557
at Foundation.NSAsyncActionDispatcher.Apply () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.9.1.24/src/Xamarin.iOS/Foundation/NSAction.cs:163
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/11.9.1.24/src/Xamarin.iOS/UIKit/UIApplication.cs:79
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.9.1.24/src/Xamarin.iOS/UIKit/UIApplication.cs:63
at Tux.iOS.Application.Main (System.String[] args) [0x00001] in /Users/simon/Documents/AimyPlus/EceAdmin/Tux/Tux.iOS/Main.cs:17
> Xamarin.Android
Version: 8.2.0.16 (Visual Studio Community)
Android SDK: /Users/simon/Library/Developer/Xamarin/android-sdk-macosx
Supported Android versions:
6.0 (API level 23)
7.1 (API level 25)
8.0 (API level 26)
SDK Tools Version: 25.2.5
SDK Platform Tools Version: 25.0.5
SDK Build Tools Version: 25.0.3
Java SDK: /usr
java version "1.8.0_101"
Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL
Xamarin Inspector
Version: 1.4.0
Hash: b3f92f9
Branch: master
Build date: Fri, 19 Jan 2018 22:00:34 GMT
Client compatibility: 1
Apple Developer Tools
Xcode 9.2 (13772)
Build 9C40b
Xamarin.Mac
Version: 4.2.1.28 (Visual Studio Community)
Xamarin.iOS
Version: 11.9.1.24 (Visual Studio Community)
Hash: f62de472
Branch: xcode9.3
Build date: 2018-03-29 19:30:53-0400
It was an issue of the updated Xamarin.Forms 2.51444934. It happened when doing a groupped listview. In order to solve:
ListView.HasUnevenRows = false;
ListView.IsGroupingEnabled = false;
((ObservableCollection<T>)listView.ItemsSource).Clear();
ListView.HasUnevenRows = true;
ListView.IsGroupingEnabled = true;
Put similar code before replacing new data collection. The problem will be solved.
Adding those lines to listview properties works for me.
IsGroupingEnabled="false"
CachingStrategy="RecycleElement"
I am using the latest version of Xamarin.Forms. My page has a ListView which shows ViewCells containing an Image. Now I would like to react to a tap on these images. Therefore, I added this code
<Image Grid.Column="1" Source="download_cloud.png" WidthRequest="32" HeightRequest="32">
<Image.GestureRecognizers>
<TapGestureRecognizer NumberOfTapsRequired="1" Tapped="SynchronizeItem_Clicked"/>
</Image.GestureRecognizers>
</Image>
This works flawless on Android. Sadly, this is not working on iOS but causes an exception (Object reference not set to an instance). The strange thing is, that when I add this TapGestureRecognizer to a Label which is displayed next to the Image everything is working perfectly.
So, is this a bug in Xamarin.Forms on iOS or am I doing something wrong?
Edit: This is the stacktrace:
Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object
at Xamarin.Forms.Platform.iOS.EventTracker.LoadRecognizers () [0x0005d] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\EventTracker.cs:373
at Xamarin.Forms.Platform.iOS.EventTracker.OnElementChanged (System.Object sender, Xamarin.Forms.Platform.iOS.VisualElementChangedEventArgs e) [0x0004e] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\EventTracker.cs:439
at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) [0x00020] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\VisualElementRenderer.cs:279
at Xamarin.Forms.Platform.iOS.ViewRenderer`2[TView,TNativeView].OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) [0x00000] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\ViewRenderer.cs:85
at Xamarin.Forms.Platform.iOS
.ImageRenderer.<>n__0 (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) <0x13780f3f0 + 0x0005a> in <13d193f5a21b4e309afc67e0a5508db5>:0
at Xamarin.Forms.Platform.iOS.ImageRenderer+<OnElementChanged>d__2.MoveNext () [0x000d6] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\Renderers\ImageRenderer.cs:70
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.6.1.2/src/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:152
at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.6.1.2/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018
at UIKit.UIKitSynchronizationContext+<Post>c__AnonStorey0.<>m__0 () [0x00000] in /Users
/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIKitSynchronizationContext.cs:24
at Foundation.NSAsyncActionDispatcher.Apply () [0x00000] in /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/Foundation/NSAction.cs:163
--- 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 /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIApplication.cs:79
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIApplication.cs:63
at SMSIP2.iOS.Application.Main (System.String[] args) [0x00001] in C:\Users\Roland\Source\Repos\SMSIP2\SMSIP2\SMSIP2.iOS\Main.cs:12
2018-01-28 10:06:25.613 SMSIP2.iOS[73968:6382644] Unhandled managed exception:
Object reference not set to an instance of an object (System.NullReferenceException)
at Xamarin.Forms.Platform.iOS.EventTracker.LoadRecognizers () [0x0005d] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\EventTracker.cs:373
at Xamarin.Forms.Platform.iOS.EventTracker.OnElementChanged (System.Object sender, Xamarin.Forms.Platform.iOS.VisualElementChangedEventArgs e) [0x0004e] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\EventTracker.cs:439
at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) [0x00020] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\VisualElementRenderer.cs:279
at Xamarin.Forms.Platform.iOS.ViewRenderer`2[TView,TNativeView].OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) [0x00000] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\ViewRenderer.cs:85
at Xamarin.Forms.Plat
form.iOS.ImageRenderer.<>n__0 (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1[TElement] e) <0x13780f3f0 + 0x0005a> in <13d193f5a21b4e309afc67e0a5508db5>:0
at Xamarin.Forms.Platform.iOS.ImageRenderer+<OnElementChanged>d__2.MoveNext () [0x000d6] in D:\agent\_work\1\s\Xamarin.Forms.Platform.iOS\Renderers\ImageRenderer.cs:70
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.6.1.2/src/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:152
at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/11.6.1.2/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018
at UIKit.UIKitSynchronizationContext+<Post>c__AnonStorey0.<>m__0 () [0x00000] i
n /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIKitSynchronizationContext.cs:24
at Foundation.NSAsyncActionDispatcher.Apply () [0x00000] in /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/Foundation/NSAction.cs:163
--- 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 /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIApplication.cs:79
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Users/builder/data/lanes/5665/6857dfcc/source/xamarin-macios/src/UIKit/UIApplication.cs:63
at SMSIP2.iOS.Application.Main (System.String[] args) [0x00001] in C:\Users\Roland\Source\Repos\SMSIP2\SMSIP2\SMSIP2.iOS\Main.cs:12
2018-01-28 10
and this is the callback:
void SynchronizeItem_Clicked(object sender, EventArgs ee)
{
}
Edit2: When I use this code somewhere else and not in the ListView it is working on iOS, too.
Edit3: I fixed this problem now - but the solution is very strange and I do not know at all, why it is working. But here we go: My CellView contained a Grid in which I wanted to place my Image. This is not working. What is working instead is: place the Image inside a StackLayout and place this StackLayout in the Grid. This looks just like the code without the additional StackLayout and suddenly the GestureRecognizer works. Can someone tell me why this is happening?
Edit4: Apparently this is not a great solution as this Command of the GestureListener is now also executed sometimes when you click on the ViewCell instead of the Image. So this is no real solution.
I am trying to write an MvvmCross app using StoryBoards. I know there are similar questions, but I have followed the solutions and I cannot get it to work. I have referenced one of the solutions I have tried in this question.
I'll explain what I have done from the beginning, hopefully this will help in the diagnosis of my problem
Create a project using the the Universal iOS Single View App in Visual Studio.
I do the standard MvvmCross setup, adding nuget, updating AppDelegate etc.
I get it to compile.
I add a new ViewController to the iPhone storyboard. I call it LogonViewController. I set the Class, Storyboard ID and Restoration ID to LogonViewController. The LogonViewController class is generated. I change it to derive it from MvxViewController
I move the entry arrow from the RootViewController (the view controller on the storyboard when it was initially created) to point to the LogonViewController. I leave the RootViewController on the storyboard
I Change the LogonViewController class to derive from MvxViewController and set the Register attribute to LogonView eg
[Register ("LogonView")]
partial class LogonViewController
I add a label to the LogonViewController just as something to display.
I create a custom container derived from MvxTouchViewsContainers as per the post in
MVVMCross support for Xamarin.iOS Storyboards
The problem is that when the overridden method (shown below) is called in the custom container I get An invalid cast exception as it cannot cast a UIKit.UIViewController to a IMvxTouchView
I also get an arithmetic overflow exception
protected override IMvxTouchView CreateViewOfType(Type viewType, MvxViewModelRequest request)
{
return (IMvxTouchView)UIStoryboard.FromName("MyStoryBoard", null)
.InstantiateViewController(viewType.Name);
}
In the trace log I get the following errors
2015-01-28 18:12:09.833 MyApp[3743:68927] mvx:Diagnostic: 8.61 Setup: LastChance start
[0:] mvx:Diagnostic: 8.61 Setup: LastChance start
[0:]
2015-01-28 18:12:10.247 MyApp[3743:68927] mvx:Diagnostic: 9.05 Setup: Secondary end
[0:] mvx:Diagnostic: 9.05 Setup: Secondary end
[0:]
2015-01-28 18:12:10.647 MyApp[3743:68927] mvx:Diagnostic: 9.43 Showing ViewModel LogonViewModel
[0:] mvx:Diagnostic: 9.43 Showing ViewModel LogonViewModel
[0:]
2015-01-28 18:12:11.049 MyApp[3743:68927] TouchNavigation:Diagnostic: 9.83 Navigate requested
[0:] TouchNavigation:Diagnostic: 9.83 Navigate requested
2015-01-28 18:12:11.254 MyApp[3743:68927] Unknown class LogonViewController in Interface Builder file.
2015-01-28 18:12:23.962 MyApp[3743:68927] -[UIViewController bottomLayoutGuide]: guide not available before the view controller's view is loaded
System.OverflowException: Arithmetic operation resulted in an overflow.
at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
System.OverflowException: Arithmetic operation resulted in an overflow.
at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
System.OverflowException: Arithmetic operation resulted in an overflow.
at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression(EvaluationContext ctx, Object obj)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue(EvaluationContext ctx, IObjectValueSource source, ObjectPath path, Object obj, ObjectValueFlags flags)
Unhandled Exception:
System.InvalidCastException: Unable to cast object of type 'UIKit.UIViewController' to type 'Cirrious.MvvmCross.Touch.Views.IMvxTouchView'.
I'm at a loss to know what I am doing wrong here. Has anyone got any ideas? This is the versions of software installed
MvvmCross 3.5.0
Visual Studio 2012 Update 4,
Xamarin Universal Installer v3.5.0.0
Xamarin Studio 5.7 v5.7.0.661
Xamarin v3.9.236.0
Update
I took EShy's advice and added the controller and named it LogonView, however I still get a problem where the LogonViewModel is not getting contructed. The log is shown below. Any ideas?
2015-01-29 11:31:33.579 MyApp[12631:273902] mvx:Diagnostic:286.77 Message = [Failed to construct and initialize ViewModel for type MyApp.Core.ViewModels.LogonViewModel from locator MvxDefaultViewModelLocator - check InnerException for more information]
[0:] mvx:Diagnostic:286.77 Message = [Failed to construct and initialize ViewModel for type MyApp.Core.ViewModels.LogonViewModel from locator MvxDefaultViewModelLocator - check InnerException for more information]
[0:]
2015-01-29 11:31:33.985 MyApp[12631:273902] mvx:Diagnostic:287.17 Stack Trace = [ at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState, IMvxViewModelLocator viewModelLocator) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.LoadViewModel (IMvxTouchView touchView) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Views.MvxViewExtensionMethods.OnViewCreate (IMvxView view, System.Func`1 viewModelLoader) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.OnViewCreate (IMvxTouchView touchView) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerAdapter.HandleViewDidLoadCalled
[0:] mvx:Diagnostic:287.17 Stack Trace = [ at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState, IMvxViewModelLocator viewModelLocator) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.ViewModels.MvxViewModelLoader.LoadViewModel (Cirrious.MvvmCross.ViewModels.MvxViewModelRequest request, IMvxBundle savedState) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.LoadViewModel (IMvxTouchView touchView) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Views.MvxViewExtensionMethods.OnViewCreate (IMvxView view, System.Func`1 viewModelLoader) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.OnViewCreate (IMvxTouchView touchView) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerAdapter.HandleViewDidLoadCalled (System.Object sender, System.EventArgs e) [0x00000] in <filename unknown>:0
at (wrapper delegate-invoke) <Module>:invoke_void_object_EventArgs (object,System.EventArgs)
at Cirrious.CrossCore.Core.MvxDelegateExtensionMethods.Raise (System.EventHandler eventHandler, System.Object sender) [0x00000] in <filename unknown>:0
at Cirrious.CrossCore.Touch.Views.MvxEventSourceViewController.ViewDidLoad () [0x00000] in <filename unknown>:0
at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
at UIKit.UIApplication.Main (System.String[] args, IntPtr principal, IntPtr delegate) [0x00005] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:62
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:46
at MyApp.iOS.Application.Main (System.String[] args) [0x00002] in c:\MyApp.iOS\Main.cs:21 ]
(System.Object sender, System.EventArgs e) [0x00000] in <filename unknown>:0
at (wrapper delegate-invoke) <Module>:invoke_void_object_EventArgs (object,System.EventArgs)
at Cirrious.CrossCore.Core.MvxDelegateExtensionMethods.Raise (System.EventHandler eventHandler, System.Object sender) [0x00000] in <filename unknown>:0
at Cirrious.CrossCore.Touch.Views.MvxEventSourceViewController.ViewDidLoad () [0x00000] in <filename unknown>:0
at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
at UIKit.UIApplication.Main (System.String[] args, IntPtr principal, IntPtr delegate) [0x00005] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:62
at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:46
at MyApp.iOS.Application.Main (System.String[] args) [0x00002] in c:\MyApp\
MyApp.iOS\Main.cs:21 ]
[0:]
2015-01-29 11:31:34.393 MyApp[12631:273902] mvx:Diagnostic:287.58 Inner Exception message = [Problem creating viewModel of type LogonViewModel]
[0:] mvx:Diagnostic:287.58 Inner Exception message = [Problem creating viewModel of type LogonViewModel]
You should name your viewcontroller in the storyboard LogonView and not LogonViewController. That's the viewType.Name that MvvmCross is looking for.
The problem was that a service injected into the LogonViewModel used the MvvmCross Messenger plugin. I had not added the plugin via nuget to the project. The exception that informed me of this was an inner exception of an inner exception. I should have dug deeper. Thanks again to you Stuart for this help and MvvmCross goodness in general. Thanks also to EShy for the naming help.
I'm currently using MvvmCross for new app projects, and I'm trying to display a header view with a MvxListView. Reading discussions such as this has led me to understand that a headerview cannot be added after the adapter has been set, so the constructor must be overridden so that the header is added before the MvxAdapter is set. This has led me to implement the following class:
public class HeaderListView : MvxListView
{
public FrameLayout HeaderFrame { get; set; }
public HeaderListView(Context context, IAttributeSet attrs)
: this(context, attrs, new MvxAdapter(context))
{
}
public HeaderListView(Context context, IAttributeSet attrs, IMvxAdapter adapter)
: base(context, attrs, null)
{
InitializeHeader(context);
// Note: Any calling derived class passing a null adapter is responsible for setting
// it's own itemTemplateId
if (adapter == null)
return;
var itemTemplateId = MvxAttributeHelpers.ReadListItemTemplateId(context, attrs);
adapter.ItemTemplateId = itemTemplateId;
Adapter = adapter;
}
private void InitializeHeader(Context context)
{
HeaderFrame = new FrameLayout(context);
AddHeaderView(HeaderFrame);
}
}
Pay particular attention to the InitializeHeader call in the second constructor. When I comment this line out, the test application starts up fine and this HeaderListView behaves indistinguishably from a standard MvxListView. However, uncomment that line and you are greeted with a blank ListView and a number of binding errors:
MvxBind:Error: 10.86 Problem seen during binding execution for binding ItemsSource for Names - problem TargetInvocationException: Exception has been thrown by the target of an invocation.
02-02 23:33:01.948 I/mono-stdout( 2323): MvxBind:Error: 10.86 Problem seen during binding execution for binding ItemsSource for Names - problem TargetInvocationException: Exception has been thrown by the target of an invocation.
at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Binding.Bindings.Target.MvxPropertyInfoTargetBinding.SetValueImpl (System.Object target, System.Object value) [0x00000] in <filename unknown>:0
02-02 23:33:01.948 I/mono-stdout( 2323): at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
02-02 23:33:01.948 I/mono-stdout( 2323): at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <filename unknown>:0
02-02 23:33:01.958 I/mono-stdout( 2323): at Cirrious.MvvmCross.Binding.Bindings.Target.MvxPropertyInfoTargetBinding.SetValueImpl (System.Object target, System.Object value) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00000] in <filename unknown>:0
at Cirrious.MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00000] in <filename unknown>:0
InnerException was NullReferenceException: Object reference not set to an instance of an object
at Cirrious.MvvmCross.Binding.Droid.Views.MvxListView.set_ItemsSource (IEnumerable value) [0x00000] in <filename unknown>:0
at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
02-02 23:33:01.958 I/mono-stdout( 2323): at Cirrious.MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00000] in <filename unknown>:0
02-02 23:33:01.968 I/mono-stdout( 2323): at Cirrious.MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00000] in <filename unknown>:0
02-02 23:33:01.968 I/mono-stdout( 2323): InnerException was NullReferenceException: Object reference not set to an instance of an object
02-02 23:33:01.968 I/mono-stdout( 2323): at Cirrious.MvvmCross.Binding.Droid.Views.MvxListView.set_ItemsSource (IEnumerable value) [0x00000] in <filename unknown>:0
02-02 23:33:01.968 I/mono-stdout( 2323): at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
I can't make any sense at all of this error, because the only difference that causes its appearance is that I assign a header view before assigning the adapter, but that has nothing whatsoever to do with the adapter. What is the source of this error, and how can I work around it?
The full source of my sample project demonstrating this problem is available on github.
The reason has to do with the hacky way that headers and footers were added to ListView. When you add a header or footer to a ListView, when you set the adapter for the list view, it wraps your adapter in a HeaderViewListAdapter that returns the headers and footers as though they were just rows before and after the actual rows your adapter returns.
The reason this fails with MvxListView is its Adpater property which looks like this:
public new IMvxAdapter Adapter
{
get { return base.Adapter as IMvxAdapter; }
set
{
// Code to copy ItemsSource and template ID
base.Adapter = value;
}
}
It does not store the IMvxAdapter instance you give it. It just sets it in the base.Adapter and expects when it gets base.Adapter later it will be the same value it set earlier. But that is not true when headers and footers are added to the list. The class you get back from base.Adapter will be a HeaderViewListAdapter that wraps the instance of IMvxAdapter that was set earlier.
There is no good way to work around this as a user of MvxList (other than copy and change MvxList). The fix for Stuart would be to not rely on base.Adapter for the getter, but instead store the value into a field in the setter and return that from the getter.
By adding ItemsSource in the .axml file causes the List to set an Adapter and you can not add a header/footer to a listview when an Adapter is set.
I had a similar issue and ended using
MvxListWithHeader - It allows you to add a header and footer to a MvxListView.
I can't see any obvious reason behind the error.
It doesn't look like the "binding process" is being disrupted from your trace. Instead it looks like the Adapter is somehow being stuck at null.
One suggestion to help debug further - if you add a new ItemsSource to your custom list view, then this will be used for binding - and will give you a place to put a breakpoint so that you can investigate the state of the ListView control during the set_ItemsSource null reference problem.
[MvxSetToNullAfterBinding]
public new IEnumerable ItemsSource
{
get { return Adapter.ItemsSource; }
set {
// here is where null is being reported
// add a breakpoint and examine Adapter and ((ListView)this).Adapter in the watch window
Adapter.ItemsSource = value;
}
}
Beyond this, you could try copying all the MvxListView code into your view to see if that helps identify the issue.
I use MvvmCross for develop a CrossPlatform App.
I work on my Mac and I have not errors when I build my solution.
When I run it... I have this error : failed to find constructor for type Cirrious.MvvmCross.ViewModels.MvxViewModelLoader and highlights base.ViewDidLoad();
Code :
public partial class MainView : MvxViewController
{
static bool UserInterfaceIdiomIsPhone {
get { return UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Phone; }
}
public MainView ()
: base (UserInterfaceIdiomIsPhone ? "MainView_iPhone" : "MainView_iPad", null)
{
}
public override void DidReceiveMemoryWarning ()
{
// Releases the view if it doesn't have a superview.
base.DidReceiveMemoryWarning ();
// Release any cached data, images, etc that aren't in use.
}
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
// Perform any additional setup after loading the view, typically from a nib.
}
It's a default code, I just changed super-class (UIViewController to MvxViewController)
Stacktrace :
Failed to find constructor for type Cirrious.MvvmCross.ViewModels.MvxViewModelLoader
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer.IoCConstruct (System.Type type) [0x00000] in :0
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer+ConstructingResolver.Resolve () [0x00000] in :0
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer.InternalTryResolve (System.Type type, ResolveOptions resolveOptions, System.Object& resolved) [0x00000] in :0
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer.InternalTryResolve (System.Type type, System.Object& resolved) [0x00000] in :0
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer.Resolve (System.Type t) [0x00000] in :0
at Cirrious.CrossCore.IoC.MvxSimpleIoCContainer.Resolve[IMvxViewModelLoader] () [0x00000] in :0
at Cirrious.CrossCore.Mvx.Resolve[IMvxViewModelLoader] () [0x00000] in :0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.LoadViewModel (IMvxTouchView touchView) [0x00000] in :0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods+<>c_DisplayClass1.b_0 () [0x00000] in :0
at Cirrious.MvvmCross.Views.MvxViewExtensionMethods.OnViewCreate (IMvxView view, System.Func`1 viewModelLoader) [0x00000] in :0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerExtensionMethods.OnViewCreate (IMvxTouchView touchView) [0x00000] in :0
at Cirrious.MvvmCross.Touch.Views.MvxViewControllerAdapter.HandleViewDidLoadCalled (System.Object sender, System.EventArgs e) [0x00000] in :0
at (wrapper delegate-invoke) :invoke_void_this__object_EventArgs (object,System.EventArgs)
at Cirrious.CrossCore.Core.MvxDelegateExtensionMethods.Raise (System.EventHandler eventHandler, System.Object sender) [0x00000] in :0
at Cirrious.CrossCore.Touch.Views.MvxEventSourceViewController.ViewDidLoad () [0x00000] in :0
at TrainingCatalog.Touch.MainView.ViewDidLoad () [0x00002] in /Users/a_masteruser/Projects/DefaultCollection/_git/HapplyTrainingCatalog/TrainingCatalog.Touch/Views/MainView.cs:30
at (wrapper managed-to-native) MonoTouch.ObjCRuntime.Messaging:void_objc_msgSend (intptr,intptr)
at MonoTouch.UIKit.UIWindow.MakeKeyAndVisible () [0x00008] in /Developer/MonoTouch/Source/monotouch/src/UIKit/.pp-UIWindow.g.cs:129
at TrainingCatalog.Touch.AppDelegate.FinishedLaunching (MonoTouch.UIKit.UIApplication app, MonoTouch.Foundation.NSDictionary options) [0x0003c] in /Users/a_masteruser/Projects/DefaultCollection/_git/HapplyTrainingCatalog/TrainingCatalog.Touch/AppDelegate.cs:21
at (wrapper managed-to-native) MonoTouch.UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
at MonoTouch.UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0004c] in /Developer/MonoTouch/Source/monotouch/src/UIKit/.pp-UIApplication.cs:38
at TrainingCatalog.Touch.Application.Main (System.String[] args) [0x00008] in /Users/a_masteruser/Projects/DefaultCollection/_git/HapplyTrainingCatalog/TrainingCatalog.Touch/Main.cs:17
Failed to find constructor for type Cirrious.MvvmCross.ViewModels.MvxViewModelLoader
From the stack trace, I'm guessing the line that is failing is: https://github.com/MvvmCross/MvvmCross/blob/v3.1/Cirrious/Cirrious.MvvmCross.Touch/Views/MvxViewControllerExtensionMethods.cs#L44
This is looking in IoC for a type which has been registered in setup as:
protected virtual void InitializeViewModelFramework()
{
Mvx.RegisterType<IMvxViewModelLoader, MvxViewModelLoader>();
}
(from https://github.com/MvvmCross/MvvmCross/blob/v3.1/Cirrious/Cirrious.MvvmCross/Platform/MvxSetup.cs#L192)
Looking at MvxViewModelLoader, this is defined in: https://github.com/MvvmCross/MvvmCross/blob/v3.1/Cirrious/Cirrious.MvvmCross/ViewModels/MvxViewModelLoader.cs - so it should have a default public parameterless constructor added by the compiler...
With this in mind...
I'm guessing that maybe Xamarin is stripping out the constructor from your deployed binaries. This might be because of your linker settings - so please check that you have set the linker to link "SDK only". But if that doesn't help then this might be down to some Xamarin optimisation/feature - so you might need to .
As a simple workaround you could try overriding Setup so that you use:
protected override void InitializeViewModelFramework()
{
Mvx.RegisterSingleton<IMvxViewModelLoader>(() => new MvxViewModelLoader>());
}
However, even if this works, then I'd be worried that the linker might be stripping out other symbols in your app - so this might not be enough... you might need to chase this through with Xamarin.