[Bug] Xamarin.Forms label and button show flashing cursors (before and/or after the controls) when page appearing

[KevinHu-au]

Description

Xamarin.Forms label and button show flashing cursors (before and/or after the controls) for 1-2 secs when page appearing, and disappear after that. The label and button are just regular Xamarin.Forms controls (not 3rd party controls)

Steps to Reproduce

Expected Behavior

Actual Behavior

Basic Information

• Version with issue:
• Last known good version:
• IDE: Visual studio for mac (8.5.3 build 16)
• Platform Target Frameworks:
  • Android: 10.0
• Android Support Library Version:
• Nuget Packages: 28.0.0.3
• Affected Devices: Samsung A20, Samsung S7 and emulators
  Xamarin.Forms: 4.5.0.530

Screenshots

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Reproduction Link

Workaround

Did try make the label/button disabled, not help.

[jsuarezruiz]

@KevinHu-au Are those labels and buttons inside a template in a CollectionView (or CarouselView)?. In this case, this issue seems to be the same as #7281 or #10294.

[eriktack]

This happens to me if i have a grid inside a collectionview with any row using GridUnitType.Absolute for height, so labels in this row will have the "cursor":
new RowDefinition{Height = new GridLength(20, GridUnitType.Absolute)}
but not labels inside this:
new RowDefinition{Height = GridLength.Star}, // or auto

[Kubion70]

This workaround may help you with labels.
Create class in android project:

public class CustomLabelRenderer : Xamarin.Forms.Platform.Android.FastRenderers.LabelRenderer
{
    public CustomLabelRenderer(Context context)
        : base(context)
    {
    }

    protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
    {
        base.OnElementChanged(e);

        if (Control == null)
        {
            return;
        }

        Control.HorizontalScrollBarEnabled = false;
        Control.VerticalScrollBarEnabled = false;
    }
}

Then add to android project AssemblyInfo (or over created class namespace if you wish) following code:

[assembly: ExportRenderer(typeof(Label), typeof(CustomLabelRenderer))]

[KevinHu-au]

@KevinHu-au Are those labels and buttons inside a template in a CollectionView (or CarouselView)?. In this case, this issue seems to be the same as #7281 or #10294.

There is not a CollectionView or CarouselView on this page. But I do use PancakeViews (https://github.com/sthewissen/Xamarin.Forms.PancakeView) for the white blocks. (But have tried Frame to replace pancakeview, the issue is still there)

The above screen has UI hierarchy roughly like this. A grid with two rows. The first row contains a scroll view, and the second row contains a Xamarin.Forms button. Each white block is a pancake view with a bunch of labels

 <Grid.RowDefinitions>
     <RowDefinition Height="*"/>
     <RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
 <ScrollView>
      <StackLayout>
            <pancake:PancakeView>
                     <StackLayout> 
                            <Label  ..../>
                     </StackLayout>
            </pancake:PancakeView>

            <pancake:PancakeView>
                     <StackLayout> 
                            <Label  ..../>
                     </StackLayout>
            </pancake:PancakeView>
      </StackLayout>
 </ScrollView>

  <!-- The bottom red button-->
  <Button Grid.Row="1"/></Grid> 

[KevinHu-au]

This workaround may help you with labels.
Create class in android project:

public class CustomLabelRenderer : Xamarin.Forms.Platform.Android.FastRenderers.LabelRenderer
{
    public CustomLabelRenderer(Context context)
        : base(context)
    {
    }

    protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
    {
        base.OnElementChanged(e);

        if (Control == null)
        {
            return;
        }

        Control.HorizontalScrollBarEnabled = false;
        Control.VerticalScrollBarEnabled = false;
    }
}

Then add to android project AssemblyInfo (or over created class namespace if you wish) following code:

[assembly: ExportRenderer(typeof(Label), typeof(CustomLabelRenderer))]

@Kubion70 . Thanks for your recommendation. It is working perfectly. Thanks for your rescue me out.

[KevinHu-au]

Did the same for button to fix this issue

[samhouts]

Duplicate of #9019

[samhouts]

Duplicate of #9591

[eriktack]

Thanks @Kubion70, that will work for me until a proper fix is out.