Xamarin中的重叠如何形成？

Question

z-index的概念是什么？图为没有重叠. 如何设置z-index？前两个自定义选择框

<AbsoluteLayout Padding="10,10,10,10" VerticalOptions="FillAndExpand">

    <ui:BoxSelector x:Name="selectorExchangs"
                    AbsoluteLayout.LayoutBounds="0,0,0.5,0.3"
                    AbsoluteLayout.LayoutFlags="All"
                    BackgroundColor="Transparent"
                    CommandAfterChanged="{Binding ExchangesAfterChangedCommand}"
                    Items="{Binding ExchangesList}"
                    LabelPath="Name"
                    PanelColor="#f9f9f9"
                    SelectedItem="{Binding SelectedExchange}"
                    SelectorLabel="EXCHANGE" />

    <ui:BoxSelector AbsoluteLayout.LayoutBounds="1,0,0.5,0.3"
                    AbsoluteLayout.LayoutFlags="All"
                    BackgroundColor="Transparent"
                    CommandAfterChanged="{Binding TradingPairAfterChangedCommand}"
                    Items="{Binding AvailableTradinPairsList}"
                    LabelPath="PriceCurrencyName"
                    PanelColor="#f9f9f9"
                    SelectedItem="{Binding SelectedTraingPair}"
                    SelectorLabel="CURRENCY" />

其余的都是.图表,数据等

    <StackLayout AbsoluteLayout.LayoutBounds="1,1,1,0.9" AbsoluteLayout.LayoutFlags="All">...</StackLayout>

BoxSelector.xaml(内容视图),可重用的ContentView扩展

<ContentView.Resources>
    <ResourceDictionary x:Name="AppDictionary">
        <Color x:Key="BackgroundColor">#f9f9f9</Color>
        <Color x:Key="BorderColor">#e2e2e2</Color>
        <Style x:Key="InternalViewStyle" TargetType="ContentView">
            <Setter Property="BackgroundColor" Value="{StaticResource BackgroundColor}" />
            <Setter Property="VerticalOptions" Value="Fill" />
            <Setter Property="Padding" Value="5,5,5,5" />
        </Style>
        <Style x:Key="BorderStyle" TargetType="ContentView">
            <Setter Property="BackgroundColor" Value="{StaticResource BorderColor}" />
            <Setter Property="Padding" Value="1,1,1,1" />
        </Style>
    </ResourceDictionary>
</ContentView.Resources>

<StackLayout BindingContext="{x:Reference Name=ContentView}" HorizontalOptions="FillAndExpand">
    <ContentView BackgroundColor="#f5f5f5" HorizontalOptions="FillAndExpand">
        <StackLayout>
            <ContentView Style="{StaticResource BorderStyle}">
                <ContentView Style="{StaticResource InternalViewStyle}">
                    <StackLayout Orientation="Horizontal">
                        <StackLayout x:Name="selectorBox"
                                     BackgroundColor="{Binding PanelColor}"
                                     HorizontalOptions="FillAndExpand"
                                     Orientation="Horizontal">
                            <StackLayout HorizontalOptions="StartAndExpand" Orientation="Horizontal">
                                <Label FontSize="12"
                                       HorizontalOptions="FillAndExpand"
                                       Text="{Binding SelectorLabel}"
                                       TextColor="#cccccc" />
                                <Label x:Name="valueLabe"
                                       BackgroundColor="{Binding PanelColor}"
                                       FontSize="13"
                                       HorizontalOptions="FillAndExpand"
                                       Text="Choose"
                                       TextColor="#313131" />
                            </StackLayout>
                            <StackLayout HorizontalOptions="EndAndExpand">
                                <Label Text="+" TextColor="#313131" />
                            </StackLayout>
                        </StackLayout>
                    </StackLayout>
                </ContentView>
            </ContentView>

            <Grid x:Name="boxSelectorGrid"
                  BackgroundColor="#f5f5f5"
                  Padding="10,10,10,10">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="*" />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
            </Grid>

        </StackLayout>
    </ContentView>
</StackLayout>

Answer 1

Z-Index是通过容器元素中的Child元素的排序建立的.第一个孩子在Z堆栈的后面,第二个孩子在它上面,依此类推.

您正在使用的布局容器将决定每个孩子的定位方式.A StackLayout不允许重叠.AbsoluteLayout并且RelativeLayout可以轻松实现重叠.A Grid将允许重叠扩展到同一行和列的元素.这些都没有自己的外观(默认情况下将它们视为透明框).如果您希望它们遮挡背后的内容,则需要指定背景颜色或图像,否则它们将仅绘制在其他内容的顶部.