c# - Xamarin.forms 如何滚动使用 AbsoluteLayout

Question

我有这个 .XAML 页面，但 Scroll 不起作用当我删除 AbsoluteLayout 并采用 stacklayout 时，它工作正常。

<ScrollView>
    <AbsoluteLayout>
        <ListView x:Name="lstView" ItemsSource="{Binding Items}" AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1"
       ItemSelected="lstView_ItemSelected">

            <ListView.Header>
                <Label Text="Store Allocation" BackgroundColor="White" TextColor="Black" FontAttributes="Bold" HorizontalOptions="Fill" HorizontalTextAlignment="Center"  />

            </ListView.Header>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <TextCell Text="{Binding Title}"  Height="200" Detail="{Binding Detail}" DetailColor="Black" TextColor="Red"  />
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        <BoxView AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1" BackgroundColor="LightGray" Opacity="0.7" InputTransparent="False" IsVisible="{Binding Path=IsBusy, Source={x:Reference Page}}" />
        <ActivityIndicator IsRunning="{Binding Path=IsBusy, Source={x:Reference Page}}" AbsoluteLayout.LayoutFlags="PositionProportional" AbsoluteLayout.LayoutBounds=".5,.5,-1,-1" />
    </AbsoluteLayout>
</ScrollView>

Answer 1

您的 XAML 基本上“说”在页面上放置一个 ScrollView，并用一个 AbsoluteLayout 填充该 ScrollView .由于内部布局完全适合 ScrollView，因此无需滚动。此外 ListView 和 BoxView 被设置为占用整个 AbsoluteLayout (AbsoluteLayout.LAyoutBounds="0,0,1,1 "), 不多也不少。为什么应该 ScrollView 滚动？

此外，如果它以这种方式工作，您将滚动 ActivityIndi​​cator 和其他所有内容，这可能不是您想要的。我假设您希望将 ActivityIndi​​cator 保留在 ListView 之上。

您可以尝试(我不是 100% 确定，但它应该有效)是仅使用 ScrollView 包装 ListView 并将 ScrollView 在 AbsoluteLayout 中这样，ScrollView 将识别 ListView 对于屏幕来说太大并启用滚动，而其他所有内容留在原地:

<AbsoluteLayout>
    <ScrollView AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1">
        <ListView x:Name="lstView" ItemsSource="{Binding Items}"
            ItemSelected="lstView_ItemSelected">
            <ListView.Header>
                <Label Text="Store Allocation" BackgroundColor="White" TextColor="Black" FontAttributes="Bold" HorizontalOptions="Fill" HorizontalTextAlignment="Center"  />
            </ListView.Header>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <TextCell Text="{Binding Title}"  Height="200" Detail="{Binding Detail}" DetailColor="Black" TextColor="Red"  />
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </ScrollView>
    <BoxView AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1" BackgroundColor="LightGray" Opacity="0.7" InputTransparent="False" IsVisible="{Binding Path=IsBusy, Source={x:Reference Page}}" />
    <ActivityIndicator IsRunning="{Binding Path=IsBusy, Source={x:Reference Page}}" AbsoluteLayout.LayoutFlags="PositionProportional" AbsoluteLayout.LayoutBounds=".5,.5,-1,-1" />
</AbsoluteLayout>