Xamarin Forms listview out of memory error - xamarin

Question

In Xamarin Forms i have the following listview:
<ListView x:Name="StudentView" RowHeight="55" SeparatorVisibility="None" CachingStrategy="RecycleElement">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="55"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Image Source="{Binding Image}" Grid.Row="0" Grid.Column="0" Aspect="AspectFill"></Image>
<Image Source="{Binding Image}" Grid.Row="0" Grid.Column="1" Aspect="AspectFill"></Image>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
In the code behind i have declared an array of 1000 items.
The problem is that if i scroll up and down the listview, everytime i see in the xamarin profile that the memory usage increase and seems that CachingStrategy="RecycleElement" not work properly (tested on real android device).
After scroll some times, the program crash with out of memory.
What's the problem? How can i resolve it?

Answer 1

Not sure how you are setting the ItemSource of the list view, or what it is. It would be useful to also show some of the code-behind file for this.
As a blind guess there can be performance issues with the recycling if your source is not indexable. The recommendation from Xamarin is to use an IList for the itemsource, using something like an IEnumerable will cause performance issues for a large array because it essentially has to keep looping through the data to find the right item for display.

Answer 2

1000 Image items are a lot! I bet this is Android, I suggest to use different solutions like:
1.- Pagging strategies (Load 10, the load another 10 and so).
2.- Reduce the images sizes.
3.- Use a cacheable image like:
https://github.com/luberda-molinet/FFImageLoading
4.- Implement a View custom renderer with a Recycler view.
And then the topic gets bigger and bigger on how you can improve your ListView performance, here are some useful links:
-https://developer.xamarin.com/guides/android/deployment,_testing,_and_metrics/performance/
-https://blog.xamarin.com/creating-highly-performant-smooth-scrolling-android-listviews/
-https://blog.xamarin.com/tips-for-creating-a-smooth-and-fluid-android-ui/
-http://kent-boogaart.com/blog/jason-smith's-xamarin-forms-performance-tips

Answer 3

I had the same issue , large list of images or images with large resolution causes this problem, I solved this by using FFImageLoading found here, also available on nuget , Also try to bind thumbnails instead of the actual Image if possible.
<ContentPage xmlns:ci="clr-namespace:FFImageLoading.Forms;assembly=FFImageLoading.Forms">
<ci:CachedImage Source="{Binding ActualImageThumbnail}" Aspect="Fill"/>