[Bug] Image sizing problem with CarouselView inside an Expander

[Softtinn]

Description

The Expander control behaves strangely when a CarouselView is set as its content. The images are being shown as thumbnails instead of their acutal size after the content is collapsed. See the included .GIF-file.

Steps to Reproduce

1. Setup the Expander control according to the official documentation.
2. Inside the Expander, add a CarouselView as the Content.
3. Feed the CarouselView with a few images (web-source).

See the code below:
<Expander.Header> // Some labels ... </Expander.Header> <StackLayout> <CarouselView HeightRequest="240" IndicatorView="indicatorView" ItemsSource="{Binding Images}"> <CarouselView.ItemTemplate> <DataTemplate> <Image Aspect="AspectFit" IsOpaque="True" Source="{Binding Value}" /> </DataTemplate> </CarouselView.ItemTemplate> </CarouselView> <IndicatorView x:Name="indicatorView" HorizontalOptions="Center" IndicatorColor="LightGray" SelectedIndicatorColor="DarkGray" /> </StackLayout> </Expander>

Expected Behavior

You should be able to hide/show the CarouselView inside the Expander without the images being shown as thumbnails.

Actual Behavior

The images inside the CarouselView are shown as thumbnails when the content is collapsed/shown. Please see the included .GIF file.

Basic Information

• Version with issue: Xamarin.Forms version: 4.7.0.1239
• Last known good version: Unknown
• IDE: Visual Studio 2019 Pro, v. 16.5.4
• Platform Target Frameworks:
  • Android: Android 9.0 (API Level 28)
• Android Support Library Version: v28.0.0.3
• Affected Devices:
  • Samsung S10+ (physical device)
  • Pixel 2 (emulator)

Screenshots

Screenshots

Reproduction Link

Example project

[PureWeen]

Seems to work fine on iOS

[jpacov]

Agree with @PureWeen, the issue only happens on Android, but not on iOS.

[thomasgalliker]

@AndreiMisiukevich will Expander still be part of Xamarin Forms in future releases? As I understand, Expander will be moved to some 3rd party library.

[AndreiMisiukevich]

@AndreiMisiukevich will Expander still be part of Xamarin Forms in future releases? As I understand, Expander will be moved to some 3rd party library.

Expander now is a part of XamarinCommunityToolkit (As you can see this ticket was moved to this project).
So, it's out of Xamarin.Forms box, but still under Microsoft's attention (it's hosted on official Xamarin GitHub account)

[thomasgalliker]

@AndreiMisiukevich okay, I'm not sure if this is the best decision. Some time ago they summarized a huge bunch of Xamarin plugins into Xamarin.Essentials. One of the reasons was to reduce app startup time (by having fewer dlls referenced?!). Now, we split parts of Xamarin.Forms off to another library. I just hope this ends up well 👍

[thomasgalliker]

@Softtinn I'm having the same issue with Expander when I use a CarouselView as Content. When I set the animation length and duration to 0, the CarouselView works as expected:

<Expander
  ExpandAnimationEasing="{x:Static Easing.CubicIn}"
  ExpandAnimationLength="0"
  CollapseAnimationEasing="{x:Static Easing.CubicOut}"
  CollapseAnimationLength="0"
  ...

It's just a workaround; I'd love to have the animations back.

[Cfun1]

@pictos you moved this issue to done (not sure if it was intended to move it or mistake), shouldn't be closed? (don't know the context)

[Softtinn]

@Cfun1 this is still an existing problem. Although setting the animation to 0 seems to be working, it would be better to fix the problem and keep the beautiful animations.