Xamarin Forms相對布局不會堆疊

Question

使用以下代碼：

<ScrollView Orientation="Vertical" Padding="0">
            <RelativeLayout BackgroundColor="Red" Padding="0">
                <BoxView Color="Blue" WidthRequest="100" HeightRequest="100" 
                RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=0}" 
                RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=0}" />
            </RelativeLayout>
            <RelativeLayout BackgroundColor="Green" Padding="0">
                <BoxView Color="Yellow" WidthRequest="100" HeightRequest="100" 
                RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=0}" 
                RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=0}" />
            </RelativeLayout>
        </ScrollView>

但是由於某種原因，每個新的相對布局都不會像堆疊那樣占據整個屏幕，如下所示：

他們為什么不垂直堆疊？ 堆棧布局通常只會垂直或水平地獲取其子項的組合高度，但是相對布局不會發生這種情況。 我想念什么？

Answer 1

試試這種布局。 我在ScrollView中添加了StackLayout，並為RelativeLayouts添加了VerticalOptions =“ Start”。

<?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="TestChat.ChatPage">
    <ContentPage.Content>
<ScrollView Orientation="Vertical" Padding="0">
    <StackLayout>
            <RelativeLayout BackgroundColor="Red" Padding="0" VerticalOptions="Start">
                <BoxView Color="Blue" WidthRequest="100" HeightRequest="100" 
                RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=0}" 
                RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=0}" />
            </RelativeLayout>
            <RelativeLayout BackgroundColor="Green" Padding="0" VerticalOptions="Start">
                <BoxView Color="Yellow" WidthRequest="100" HeightRequest="100" 
                RelativeLayout.XConstraint="{ConstraintExpression Type=Constant, Constant=0}" 
                RelativeLayout.YConstraint="{ConstraintExpression Type=Constant, Constant=0}" />
            </RelativeLayout>
            </StackLayout>
        </ScrollView>
    </ContentPage.Content>
</ContentPage>