Binding PickerCell on SelectedItem crash on Android and iOS

[mattiasskog]

Description

When binding to SelectedItem I get Object refrerence not set to an instance of an object.
If I remove the binding the view is opened.

Steps to Reproduce

1. Add a PickerCell
   <renderers:PickerCell
   Title="TitelOfPicker"
   ItemsSource="{Binding PickerItems}"
   DisplayMember="Name"
   SelectionMode="Single"
   SelectedItem="{Binding PrimaryPickerItem}"
   SelectedCommand="{Binding PickerSelectedCommand}"
   KeepSelectedUntilBack="true"
   PageTitle="Choose your item!" />

2. Binding is on
   public ReadOnlyObservableCollection PickerItems { get; }

3. PrimaryPickerItem
   public ItemDataV1 PrimaryPickerItem
   {
   get { return _primaryPickerItem; }
   set { SetProperty(ref _primaryPickerItem, value); }
   }

Expected Behavior

View would open

Actual Behavior

Object reference not set to an instance of an object.

10-25 20:16:28.588 I/MonoDroid(11399): UNHANDLED EXCEPTION:
10-25 20:16:28.592 I/MonoDroid(11399): System.NullReferenceException: Object reference not set to an instance of an object.
10-25 20:16:28.592 I/MonoDroid(11399): at AiForms.Renderers.PickerCell.GetSelectedItemsText () [0x0015a] in <372a7272679343959209201f0047d05b>:0
10-25 20:16:28.592 I/MonoDroid(11399): at AiForms.Renderers.Droid.PickerCellView.UpdateSelectedItems (System.Boolean force) [0x00079] in :0
10-25 20:16:28.592 I/MonoDroid(11399): at AiForms.Renderers.Droid.PickerCellView.UpdateCell () [0x00006] in :0
10-25 20:16:28.592 I/MonoDroid(11399): at AiForms.Renderers.Droid.CellBaseRenderer1[TnativeCell].GetCellCore (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context) [0x00046] in <c11b61fab6d348b1b3bb9252504613f0>:0 10-25 20:16:28.592 I/MonoDroid(11399): at Xamarin.Forms.Platform.Android.CellRenderer.GetCell (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context) [0x00075] in D:\a\1\s\Xamarin.Forms.Platform.Android\Cells\CellRenderer.cs:51 10-25 20:16:28.592 I/MonoDroid(11399): at Xamarin.Forms.Platform.Android.CellFactory.GetCell (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context, Xamarin.Forms.View view) [0x0001e] in D:\a\1\s\Xamarin.Forms.Platform.Android\Cells\CellFactory.cs:20 10-25 20:16:28.592 I/MonoDroid(11399): at AiForms.Renderers.Droid.SettingsViewRecyclerAdapter.BindContentView (AiForms.Renderers.Droid.ContentBodyViewHolder holder, System.Int32 position) [0x00043] in <c11b61fab6d348b1b3bb9252504613f0>:0 10-25 20:16:28.593 I/MonoDroid(11399): at AiForms.Renderers.Droid.SettingsViewRecyclerAdapter.OnBindViewHolder (AndroidX.RecyclerView.Widget.RecyclerView+ViewHolder holder, System.Int32 position) [0x000d3] in <c11b61fab6d348b1b3bb9252504613f0>:0 10-25 20:16:28.593 I/MonoDroid(11399): at AndroidX.RecyclerView.Widget.RecyclerView+Adapter.n_OnBindViewHolder_Landroidx_recyclerview_widget_RecyclerView_ViewHolder_I (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_holder, System.Int32 position) [0x00010] in D:\a\1\s\generated\androidx.recyclerview.recyclerview\obj\Release\monoandroid90\generated\src\AndroidX.RecyclerView.Widget.RecyclerView.cs:425 10-25 20:16:28.593 I/MonoDroid(11399): at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.46(intptr,intptr,intptr,int) 10-25 20:16:28.605 E/AppCenterCrashes(11399): Unhandled Exception from source=AndroidEnvironment 10-25 20:16:28.605 E/AppCenterCrashes(11399): System.NullReferenceException: Object reference not set to an instance of an object. 10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.PickerCell.GetSelectedItemsText () [0x0015a] in <372a7272679343959209201f0047d05b>:0 10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.Droid.PickerCellView.UpdateSelectedItems (System.Boolean force) [0x00079] in <c11b61fab6d348b1b3bb9252504613f0>:0 10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.Droid.PickerCellView.UpdateCell () [0x00006] in <c11b61fab6d348b1b3bb9252504613f0>:0 10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.Droid.CellBaseRenderer1[TnativeCell].GetCellCore (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context) [0x00046] in :0
10-25 20:16:28.605 E/AppCenterCrashes(11399): at Xamarin.Forms.Platform.Android.CellRenderer.GetCell (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context) [0x00075] in D:\a\1\s\Xamarin.Forms.Platform.Android\Cells\CellRenderer.cs:51
10-25 20:16:28.605 E/AppCenterCrashes(11399): at Xamarin.Forms.Platform.Android.CellFactory.GetCell (Xamarin.Forms.Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context, Xamarin.Forms.View view) [0x0001e] in D:\a\1\s\Xamarin.Forms.Platform.Android\Cells\CellFactory.cs:20
10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.Droid.SettingsViewRecyclerAdapter.BindContentView (AiForms.Renderers.Droid.ContentBodyViewHolder holder, System.Int32 position) [0x00043] in :0
10-25 20:16:28.605 E/AppCenterCrashes(11399): at AiForms.Renderers.Droid.SettingsViewRecyclerAdapter.OnBindViewHolder (AndroidX.RecyclerView.Widget.RecyclerView+ViewHolder holder, System.Int32 position) [0x000d3] in :0
10-25 20:16:28.605 E/AppCenterCrashes(11399): at AndroidX.RecyclerView.Widget.RecyclerView+Adapter.n_OnBindViewHolder_Landroidx_recyclerview_widget_RecyclerView_ViewHolder_I (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_holder, System.Int32 position) [0x00010] in D:\a\1\s\generated\androidx.recyclerview.recyclerview\obj\Release\monoandroid90\generated\src\AndroidX.RecyclerView.Widget.RecyclerView.cs:425
10-25 20:16:28.605 E/AppCenterCrashes(11399): at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.46(intptr,intptr,intptr,int)
10-25 20:16:28.617 D/Mono (11399): Requesting loading reference 5 (of 6) of /storage/emulated/0/Android/data/se.ceecube.matchup/files/.override/Microsoft.AppCenter.Crashes.dll

Platforms

• Android
• iOS

Basic Information

• AiForms.SettingsView 1.3.3
• Xamarin.Forms 4.8.0.1560
• Affected Devices:

Screenshots

Reproduction Link

Workaround

Do not bind to SelectedItem

[mattiasskog]

Might be related to issue #115