Android Performance while scrolling long list of items

[abel-coding]

Describe the bug

Very Simple Code Like this will produce far from smooth scrolling on Android real Device. I compare similar (and more complex equivalent that include actual image loading) codes on MAUI and Flutter and the performance is much better. There is any particular configuration needed for Android ir order to achieve a decent scrolling

  <ListBox ItemsSource="{Binding Items}">
    <ListBox.ItemsPanel>
      <ItemsPanelTemplate>
        <VirtualizingStackPanel/>
      </ItemsPanelTemplate>
    </ListBox.ItemsPanel>
    <ListBox.ItemTemplate>
      <DataTemplate DataType="vm:ItemsViewModel">
        <Border Margin="0" HorizontalAlignment="Stretch" Padding="0">
          <Grid ColumnDefinitions="Auto, *" HorizontalAlignment="Stretch">
            <Border CornerRadius="8" Background="LightGray" Width="60" Height="60" HorizontalAlignment="Center" VerticalAlignment="Center">
              <Image/>  
            </Border>
            <StackPanel Grid.Column="1" Orientation="Vertical" VerticalAlignment="Center" HorizontalAlignment="Stretch">
              <Label FontSize="16"
                     Margin="8"
                     Content="{Binding Title}"/>
              <Label Margin="8" 
                     Content="{Binding Description}"
                     FontSize="12"/>
            </StackPanel>
          </Grid>
        </Border>
      </DataTemplate>
    </ListBox.ItemTemplate>
  </ListBox>

To Reproduce

Sample provided Template. Please test on a real device. Compiled Binding does not solve the problem.

Expected behavior

Smooth scrolling

Avalonia version

11.2.1

OS

Android

Additional context

No response

[maxkatz6]

Make sure you are running Release, with or without AOT for comparison.
Making AOT profile for your application is very advised too. See #1 and #2.

It still won't be as fast as Flutter with native compilation, until .NET gets NativeAOT support for Android which is worked on. Likely in .NET 10 we will have early previews of that. MAUI is different and can't be compared directly, since they use native controls for everything, so during scrolling little-to-no C# code is actually executed.

Sample provided Template. Please test on a real device. Compiled Binding does not solve the problem.

I would be much easier with the rest of the code.

[maxkatz6]

Image control is suspicious here. If in your actual code there is source set, it might be a bigger reason for poor performance. If this image is bigger than configured Skia GPU cache that can be increased if that's the case.

[abel-coding]

Image source was never set. I also attached whole project. I compile to device on Release and test multiple AoT flags but still I have to look into a more curated AoT approach as #1 and #2. Is still hard for me to believe why the poor performance on a very simple layout/use case.

AvaloniaApplication1.zip

[msneijders]

You could test what I did, in this discussion: #17511 (reply in thread)
With a custom ListBox, I could cut quite some layout calculations of the recycled containers by not resetting their contents -- this helped me a lot for listbox scrolling on (lower- to mid-end) android devices. The trick in that discussion prevents the same resetting, without a custom listbox.

Profiling could give insights, using dotnet tracing

Also try and prevent using 'Auto' in layouts of your itemtemplate; in my experience performance is mostly about cutting layout calcs.

[abel-coding]

I tried approach with custom ListBox suggested on #17511 but no good results. I haven't profile but I what I can say is there is no client code, the is no client logic, there is no async image/content loading. This is just a simple layout of a fixed list of elements.

I tried equivalent code with other frameworks on the same physical device (Pixel 5) and there performance is so much better. I am just wondering if there some extra configuration that Avalonia does not provide out of the box for fixing this.

[msneijders]

I am just wondering if there some extra configuration that Avalonia does not provide out of the box for fixing this.

No, there is no configuration with listbox to improve its layout performance. In my experience only trying to prevent the content reset of the recycled elements, which should cut layout timings by half.

As an alternative you could try out ItemsRepeater, which is doing the virtualization a bit different compared to ListBox I believe–but it does not have the same feature set as ListBox.