Xamarin.Forms - Label text disappears on android in Listview

dai15002

As the code shows below, I did bind a label to the myViewModel's string LabelInfo. When I receive the data in scrollview, everything shows fine on Android and iOS. But on Android when I scroll down or up until the label is not shown and then I scroll back again, the label text is dissapeard and it appears again when I bring the phone keyboard up again by pressing a searchBar above the listview. Is there a way to force showing/rendering the label text?

<ListView.ItemTemplate >




<Grid.ColumnDefinitions >






</Grid.ColumnDefinitions>
<Grid.RowDefinitions>

                                                    </Grid.RowDefinitions>

                                          ..........

                                                    <StackLayout Grid.Column="3" Grid.Row="1" Orientation="Vertical">
                                                        <Label Text="{Binding UserName}"  FontSize="15" FontAttributes="Bold" TextColor="#474747"  VerticalOptions="Center" FontFamily="{StaticResource EncodeSansSemiCondensed-Bold}"/>

                                                        <StackLayout Padding="0" Orientation="Horizontal">

                                //the labelinfo text dissapears when outside listview
                                                            <Label Text="{Binding LabelInfo}" TextDecorations="Underline" TextColor="#3366BB" LineBreakMode="TailTruncation"  FontFamily="{StaticResource EncodeSansSemiCondensed-Bold}" FontSize="10">
                                                                <Label.GestureRecognizers>
                                                                    <TapGestureRecognizer Tapped="ShowCompToastInfo" />
                                                                </Label.GestureRecognizers>
                                                            </Label>
                                                        </StackLayout>

                                                    </StackLayout>

                                                     .........

                                                </Grid>
                                        </StackLayout>
                                    </ViewCell>
                                </DataTemplate>
                            </ListView.ItemTemplate>

AlessandroCaliaro

Try CollectionView

dai15002

the collectionview does not have the properties below that the listview has and also i get the error "No property, bindable property, or event found for 'GroupHeaderTemplate', or mismatching type between value and property"

            CachingStrategy="RecycleElement" 
                            IsGroupingEnabled="True"
                            SeparatorVisibility="None"
                            HasUnevenRows="true"
                            ItemTapped="myUserList_ItemTapped"

AlessandroCaliaro

With CollectionView
1- you don't need RecycleElement
2- does not include built-in separators; users can provide these (if desired) in their templates.
3- does not need HasUnevenRows
4- use SelectedItemCommand instead of ItemTapped
5- Grouping: https://docs.microsoft.com/it-it/xamarin/xamarin-forms/user-interface/collectionview/grouping

dai15002

The property does not have SelectedItemCommand

Is there an easier way to force rendering since CollectionView must use bindable data?

AlessandroCaliaro

@dai15002 said:
The property does not have SelectedItemCommand

Is there an easier way to force rendering since CollectionView must use bindable data?

I don't understand… what does it mean "the property does not have SelectedItemCommand"? SelectedItemCommand is a Command that is raised when you select an item on CollectionView and you can use it in MVVM.

dai15002

Thanks. The problem was due to the CachingStrategy of the listview.