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The top of SfListView doesn't align with first item group

I am using the SfListView control with Xamarin Forms to create an expandable grouped list. After grouping the items and updating the data source, the top of the listview doesn't properly align with the first item in the collection. After loading the listview, the listview displays the first item in the collection properly aligned with the padding/margins however when scrolling, you are able to slide the listview above the first item; leaving a weird space between that doesn't go away. I tried changing the padding but the padding shrinked the listview without fixing the problem. I tried using margins and had the same result. I tried making the Group Header Size smaller and bigger and this didn't fix the problem either. I also tried to use every AutoFitMode property value and still ended up with the same results. Can somebody please help me? I have no clue why this is happening.

<Stacklayout>
    <lv:SfListView ItemsSource="{Binding TestSource}" DataSource="{Binding TestGrouping}" IsScrollBarVisible="True" Padding="10" SelectionMode="None" ItemSize="90" RowSpacing="0" IsVisible="{Binding HideIfEmpty}" AllowGroupExpandCollapse="True" GroupHeaderSize="30">
        <lv:SfListView.GroupHeaderTemplate>
            <DataTemplate x:DataType="de:GroupResult">
                <FlexLayout AlignItems="Center" JustifyContent="SpaceBetween" Direction="Row" BackgroundColor="Gray">
                    <StackLayout Orientation="Horizontal">
                        <Label Text="{Binding Key}"/>
                        <Label>
                            <Label.FormattedText>
                                <FormattedString>
                                    <Span Text="("/>
                                    <Span Text="{Binding Count}"/>
                                    <Span Text=")"/>
                                </FormattedString>
                            </Label.FormattedText>
                        </Label>
                    </StackLayout>
                    <Label Text="{Binding IsExpand, Converter={StaticResource IsExpandedToIcon}}" Style="{StaticResource ListGroupIcon}"/>
                </FlexLayout>
            </DataTemplate>
        </lv:SfListView.GroupHeaderTemplate>
    </lv:SfListView>
</Stacklayout>

Attachment: Images_b6e4683a.zip

6 Replies

SY Suthi Yuvaraj Syncfusion Team November 9, 2022 08:36 AM

We are unable to reproduce the issue at our end. We have created a sample with updating datasource and grouping ,issue is not replicated at our end. With the provided code snippet we suspect that you have used scrollview in your sample, as the content size is less than the screen size, the scrollbar will not be visible even though IsScrollVisible is set to true in SfListView . We have attached the tested sample for your reference, please have a look on it and let us know if we have missed any other customization that you have done in your sample and we have attached the documentation for your reference.


UG Link:

https://help.syncfusion.com/xamarin/listview/grouping?cs-save-lang=1&cs-lang=csharp/

https://help.syncfusion.com/xamarin/listview/getting-started#datasource


Also could you please modify the sample to reproduce the issue or share the below details which will be helpful for us to find the solution as soon as possible.

  1. Code snippet related data population
  2. Code snippet related to the XAML , layout in which have added the SfListView control
  3. Code snippet related to event or any customization with SfListView
  4. Syncfusion.Xamarin.SfListView and Xamarin.Forms version

Attachment: ListViewGroupHeader_6b1bd677.zip


BS Bryson Scales replied to Suthi Yuvaraj November 9, 2022 01:49 PM

Oops, I forgot to mention that I am using Xamarin.Forms v5.0.0.2515 and Xamarin.Essentials v1.7.3 with a Xamarin Forms Shell project. I am using the SfListView on a page that uses a top and bottom tabbar and the emulator emulating the program is an iPhone 14 Pro Max running iOS 16.0 with XCode v14.0.1. My AppShell.xaml looks very similar to this:

<Shell.Resources>
<...>
</Shell.Resources>
<TabBar>
    <Tab x:Name="tab1" Title="Tab1">
        <ShellContent x:Name="tab1SubTab1" Route="tab1SubTab1Page" ContentTemplate="{DataTemplate local:tab1SubTab1Page}"
    </Tab>
    <Tab x:Name="tab2" Title="Tab2">
        <ShellContent x:Name="tab2SubTab1" Route="tab2SubTab1Page" Title="Title1" ContentTemplate="{DataTemplate local:tab2SubTab1Page}"/>
        <ShellContent x:Name="tab2SubTab2" Route="tab2SubTab2Page" Title="Title2" ContentTemplate="{DataTemplate local:tab2SubTab2Page}"/>
        <ShellContent x:Name="tab2SubTab3" Route="tab2SubTab3Page" Title="Title3" ContentTemplate="{DataTemplate local:tab2SubTab3Page}"/>

    </Tab>
</TabBar>

In this example, my SfListView would be placed on any "tab2" "SubTabPage" along with a Stacklayout that's IsVisible property is binded to a "ShowIfEmpty" view model property that is always the opposite value of the "HideIfEmpty" view model property. The "ShowIfEmpty" property is false by default and whenever the value is updated it raises an OnPropertyChanged event for the "HideIfEmpty" property. After the collection's data is fetched, the same method that fetches the data and resets the DataSource Grouping and Sorting uses the following code to evaluate if the list is empty:

ShowIfEmpty = IsListEmpty();
bool IsListEmpty() 
{
    if (TestSource.Count == 0) return true;
    else return false;
}

The data sample of 15 random generated items is then grouped into 4 groups by a "GroupName" property.



BS Bryson Scales November 10, 2022 07:29 AM

After looking at my project again, I also forgot to add that I am using the SfListView inside of a SfPopupLayout that includes a SfPopupLayout.PopupView. My code looks more like this:

<pop:SfPopupLayout Style="{LoadingLayout}">
    <pop:SfPopupLayout.PopupView>
        <...>
    </pop:SfPopupLayout.PopupView>
    <pop:SfPopupLayout.Content>
        <Stacklayout>
            <lv:SfListView>
                <Code from original message...>
            </lv:SfListView>
            <Stacklayout IsVisible="{Binding ShowIfEmpty}">
            </Stacklayout>
        </Stacklayout>
     </pop:SfPopupLayout.Content>
</pop:SfPopupLayout>


SV Suja Venkatesan Syncfusion Team November 10, 2022 12:02 PM

We prepared a simple SfListView with provided code snippet and checked the reported scenario. Unfortunately, we are unable to replicate the reported scenario on our end. We have attached a sample which we used to check this for your reference. Please have a look at the sample and let us know if we missed any customization you have done in your application or revert to us with modified sample to replicate the reported scenario on our end. It will be more helpful for us to provide a timely solution.

MicrosoftTeams-image.png



BS Bryson Scales replied to Suja Venkatesan November 10, 2022 04:41 PM

My apologies for failing to include every detail related to my issue. I was able to replicate the problem in a new Xamarin Forms Shell project. The file is bigger than 30MB so I have uploaded it to DropBox.

Here is the link: https://www.dropbox.com/s/thoiu2o80be8oxk/GroupingFix.zip?dl=0


Thanks,

Bryson



SY Suthi Yuvaraj Syncfusion Team November 18, 2022 09:40 AM

We are able to reproduce the issue at our end, we have found that you have created a shellpage inside the tab on the shellpage , that we are facing the issue the extra space on the top of the listview . we have tested the scenario in the Xamarin.Forms Framework ListView , we have faced the same issue in the Framework listview , we have logged the issue in framework level as the issue occurs only if the Listview is loaded inside the shellpage with tabs inside it. Also we would like to let you know that if you load the control as a direct child inside the shellpage , the extra spacing can be avoided. we have logged this issue is logged as bug in framework level.


Please refer to the framework issue report for more reference,

Bug report: https://github.com/xamarin/Xamarin.Forms/issues/15609


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