为什么横向模式下的扩展布局在 Xamarin Forms 中显示半黑屏?

Why does extented layout on landscape mode shows half black screen in Xamarin Forms?

我有两个视图和两个内容页面,其中一个是垂直排列的,当设备处于 纵向 模式时显示,如下所示:

<StackLayout>
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="Auto"/>
                </Grid.RowDefinitions>

                <views:ScoresView Grid.Row="0"/>
                <views:CategoriesView Grid.Row="1"/>

            </Grid>
        </StackLayout>

以及横向模式

的其他内容页面
<StackLayout>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="Auto"/>
            </Grid.ColumnDefinitions>

            <views:ScoresView Grid.Column="0"/>
            <views:CategoriesView Grid.Column="1"/>
        </Grid>
    </StackLayout>

我希望它看起来像这样:

但看起来像这样:

这就是我在旋转时调用一个或另一个的方式

protected override void OnSizeAllocated(double width, double height)
        {
            base.OnSizeAllocated(width, height);
            if (width > height)
            {
                //device is landscape
                App.Current.MainPage = new CategoriesLands();
            }
            else
            {
                //device is portrait (or square)
            }
        }

您可以更改 StackLayout StackOrientation 属性 来实现效果。

<StackLayout x:Name="outerStack">       
     <views:ScoresView HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>
     <views:CategoriesView HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>
</StackLayout>

在后面的代码中:

private double width;
private double height;
protected override void OnSizeAllocated(double width, double height)
    {
        base.OnSizeAllocated(width, height);
        if (width != this.width || height != this.height)
        {
            this.width = width;
            this.height = height;
            if (width > height)
            {
                outerStack.Orientation = StackOrientation.Horizontal;
            }
            else
            {
                outerStack.Orientation = StackOrientation.Vertical;
            }
        }
    }

你可以参考的越多this