Xamarin Forms on Android: ScrollView on ListView header crashes app when closing page

[Mirksar]

Bug report best practices: https://github.com/xamarin/Xamarin.Forms/wiki/Submitting-Issues

Description

In a page with this structure:

    <ListView>
        <ListView.Header>
            <ScrollView Orientation="Horizontal">
                <StackLayout Orientation="Horizontal">
                    <BoxView Color="Green ">
                    </BoxView>
                </StackLayout>
            </ScrollView>
        </ListView.Header>
    </ListView>

The app crashes when pressing back on the device with this stack trace:

ScrollViewRenderer.Dispose (System.Boolean disposing)
D:\agent_work\1\s\Xamarin.Forms.Platform.Android\Renderers\ScrollViewRenderer.cs - line 180
System.NullReferenceException: Object reference not set to an instance of an object.
Object reference not set to an instance of an object.
ScrollViewRenderer.Dispose (System.Boolean disposing) D:\agent_work\1\s\Xamarin.Forms.Platform.Android\Renderers\ScrollViewRenderer.cs:180
Object.Dispose () /Users/builder/data/lanes/5809/413eed68/source/monodroid/external/xamarin-android/src/Mono.Android/Java.Lang/Object.cs:203
ListViewRenderer.Dispose (System.Boolean disposing) D:\agent_work\1\s\Xamarin.Forms.Platform.Android\Renderers\ListViewRenderer.cs:60
Object.Dispose () /Users/builder/data/lanes/5809/413eed68/source/monodroid/external/xamarin-android/src/Mono.Android/Java.Lang/Object.cs:203
VisualElementRenderer`1[TElement].Dispose (System.Boolean disposing) D:\agent_work\1\s\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:234
Object.Dispose () /Users/builder/data/lanes/5809/413eed68/source/monodroid/external/xamarin-android/src/Mono.Android/Java.Lang/Object.cs:203

Steps to Reproduce

Please, find atached a project that reproduces the crash. Execute the project and just press back on Android

Expected Behavior

Going back from the app doesn't crash the app

Actual Behavior

When pressing back on the navigation the app crashes

Basic Information

• Version with issue:
• Last known good version:
• IDE:
• Platform Target Frameworks:
  • Android: 8.0

Reproduction Link

https://www.dropbox.com/s/di52t93ag4kewxe/ScrollCrashTest.7z?dl=0

[HoussemDellai]

For now you can put the ScrollView inside a Grid and that should work.

<ListView>
    <ListView.Header>
        <Grid>
            <ScrollView Orientation="Horizontal">
                <StackLayout Orientation="Horizontal">
                    <BoxView Color="Green ">
                    </BoxView>
                </StackLayout>
            </ScrollView>
        </Grid>
    </ListView.Header>
</ListView>

[tekinc]

@hartez is this resolved?

[hartez]

@tekinc Yes. Fixed in XF 3.1.0 and later.

[tekinc]

@hartez I tested with 3.1.* and 3.2.* preview, both failed. My use case is on a push notification within the app, App() is called again and my mainpage is reloaded. That's when I get the exception.

[hartez]

@tekinc And your app has a ListView with a Header which contains a ScrollView?

[tekinc]

Yes it does. Tarek Ahmed TEK Inc http://www.tek.us o.(855) 354-5TEK m.917. <917.696.8126>304.9444

…

On Tue, Aug 7, 2018 at 6:22 PM, E.Z. Hart ***@***.***> wrote: @tekinc <https://github.com/tekinc> And your app has a ListView with a Header which contains a ScrollView? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1931 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABI45Xqgd4nPePkX3nmzzG-TvFLDBkPaks5uOhM0gaJpZM4SMQYL> .