[Bug] CollectionView Layout issues

[daves1992]

I noticed since switching to CollectionView from ListView there is multiple layout issues

These issues are apparent when the screen first loads but disappear when you scroll.

XAML:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MaceXamarinSharedStandardProject.Views.SelectionPage"
             x:Name="CPSelectionPage"
             Title ="{Binding Title}"
             Style="{StaticResource contentPage}">
    <ContentPage.Content>
        <StackLayout Orientation="Vertical" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Padding="0,10,0,0">
            <Entry Text="{Binding FilterText}" IsVisible="{Binding ShowFilter}" Placeholder="Filter" />
            <CollectionView x:Name="lstSelection" SelectionChangedCommand="{Binding SelectionChangedCommand}" SelectedItem="{Binding SelectedItem}" ItemsSource="{Binding SelectionList}" VerticalOptions="FillAndExpand" SelectionMode="Single" ItemSizingStrategy="MeasureAllItems">
                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Frame Style="{StaticResource borderFrame}" Padding="1" HasShadow="False" CornerRadius="0" >
                            <Frame Style="{StaticResource backgroundFrame}" Padding="10" HasShadow="False" CornerRadius="0">
                                <StackLayout Orientation="Vertical" >
                                    <Label Text="{Binding ID}" FontAttributes="Bold" Style="{StaticResource textLabel}" />
                                    <Label Text="{Binding Description}" FontSize="Small" Style="{StaticResource detailLabel}" />
                                </StackLayout>
                            </Frame>
                        </Frame>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

Issue:

• Version with issue: 4.8.0.1560

• Last known good version: Unknown

• IDE: VS 4.8.04084

• Affected Devices:
  Seems to only affect IOS

[rmarinho]

Hi @daves1992 thanks for your report, is it possible to upload a small repro of the issue so we can investigate better the problem?!

Thanks

[ClaytonIndustries]

@rmarinho You can repro this easily by creating a collection view where the items are different heights. ItemSizingStrategy="MeasureAllItems" doesn't seem to work properly on iOS, pretty sure this issue has been raised many times before, links to just a few of them

#12554
#11511
#11011
#10842

[rmarinho]

Tested with 4.8.0.1560 and 5.0.0-pre3
Seems i can reproduce this , and this happens with and without ItemSizingStrategy="MeasureAllItems"

on load:

after i scroll :

[hartez]

This is fixed in 5.0.0.1931.