In iOS only, the first time I navigate from my home page to a ListView page it renders fine. When I hit back on the navigation breadcrumb to go back to my home page... I get a runtime error "System.NullReferenceException: Object reference not set to an instance of an object"
If I use a regular Image control it works fine.
Not sure if this is related to linker options, but here is what I have tried for linker options:
I have tried Link SDK Assemblies only and none. I have added the Additional mtouch argument: --linkskip=ImageCircle.Forms.Plugin.iOS --linkskip=ImageCircle.Forms.Plugin.Abstractions
Any other ideas?
Note: I posted on the Xamarin forums too...
https://forums.xamarin.com/discussion/87828/imagecircle-causes-ios-null-reference-exception/p1?new=1
3 Answers, 1 is accepted
Thank you for contacting us! Would it be possible to share some additional information regarding the setup of the navigation as well as the layout of the page (xaml,cs) where listview resides.
Also, if you are running the app on device in debug mode can you make sure that incremental build is disabled - http://docs.telerik.com/devtools/xamarin/troubleshooting/ios-app-issues-on-device-but-not-on-simulator
Regards,
Tsvyatko
Telerik by Progress
Rank 1
Using Navigation Page to start the app, then content pages are navigated to. Note the HeighRequest need to be set really high for the images to appear. All images are embedded resources. Here is the XAML:
<telerikDataControls:RadListView HeightRequest="1500" x:Name="RADlistView"
BackgroundColor="White"
SelectedItem="{Binding objSelectedTumor, Mode=TwoWay}" >
<telerikDataControls:RadListView.ItemTemplate>
<DataTemplate>
<telerikListView:ListViewTemplateCell>
<telerikListView:ListViewTemplateCell.View>
<Grid Padding="10" RowSpacing="5" HorizontalOptions="Center" VerticalOptions="Center">
<Grid.RowDefinitions>
<RowDefinition Height="6*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<!--these options cause System.NullReferenceException: Object reference not set to an instance of an object in iOS.
HorizontalOptions="Center"
VerticalOptions="Center"-->
<controls:CircleImage Grid.Row="0"
Source="{Binding thumb_file_image_name} Converter={StaticResource ImageConverter}"
Aspect="AspectFit"
IsVisible="{StaticResource showSectionAndroidWin}"
>
<controls:CircleImage.WidthRequest>
<OnPlatform x:TypeArguments="x:Double"
iOS="55"
Android="55"
WinPhone="75"
/>
</controls:CircleImage.WidthRequest>
<controls:CircleImage.HeightRequest>
<OnPlatform x:TypeArguments="x:Double"
iOS="55"
Android="55"
WinPhone="75"
/>
</controls:CircleImage.HeightRequest>
</controls:CircleImage>
<Image Grid.Row="0"
Source="{Binding thumb_file_image_name} Converter={StaticResource ImageConverter}"
Aspect="AspectFit"
IsVisible="{StaticResource showSectioniOS}"
>
<Image.WidthRequest>
<OnPlatform x:TypeArguments="x:Double"
iOS="55"
Android="55"
WinPhone="75"
/>
</Image.WidthRequest>
<Image.HeightRequest>
<OnPlatform x:TypeArguments="x:Double"
iOS="55"
Android="55"
WinPhone="75"
/>
</Image.HeightRequest>
</Image>
<Grid Grid.Row="1"
Grid.Column="0"
RowSpacing="1"
VerticalOptions="Start"
HorizontalOptions="Center"
>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0"
Grid.Column="0"
LineBreakMode="NoWrap"
BackgroundColor="Transparent"
HorizontalTextAlignment="Center"
VerticalTextAlignment="Center"
Text="{Binding name}"
TextColor="#81AABC">
<Label.FontSize>
<OnPlatform x:TypeArguments="x:Double">
<OnPlatform.WinPhone>
<OnIdiom x:TypeArguments="x:Double">
<OnIdiom.Phone>14</OnIdiom.Phone>
</OnIdiom>
</OnPlatform.WinPhone>
<OnPlatform.Android>
<OnIdiom Phone="10"
Tablet="12"
x:TypeArguments="x:Double" />
</OnPlatform.Android>
<OnPlatform.iOS>
<OnIdiom Phone="10"
Tablet="12"
x:TypeArguments="x:Double" />
</OnPlatform.iOS>
</OnPlatform>
</Label.FontSize>
</Label>
</Grid>
</Grid>
</telerikListView:ListViewTemplateCell.View>
</telerikListView:ListViewTemplateCell>
</DataTemplate>
</telerikDataControls:RadListView.ItemTemplate>
<telerikDataControls:RadListView.LayoutDefinition>
<telerikListView:ListViewGridLayout x:Name="gridLayout"
VerticalItemSpacing="5"
HorizontalItemSpacing="5"
SpanCount="5"
ItemLength="180" />
</telerikDataControls:RadListView.LayoutDefinition>
</telerikDataControls:RadListView>
Thank you for the information. I tried to reproduce the issue on our side but to no avail. Could you please check the sample project and modify it in order to reproduce the problem.
I look forward to your reply.
Regards,
Rosy Topchiyska
Telerik by Progress