Xamarin Forms-NavigationPage.TitleView在iOS上不起作用

Question

我有一个简单的（文件->新项目）XF应用，该应用不会显示iOS的NavigationPage.TitleView内容。 Android运行正常。我在做什么错了？

可以找到源代码here。

XAML

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             x:Class="SampleApp.MainPage">

    <NavigationPage.TitleView>
        <Grid BackgroundColor="Blue">
            <Grid.RowDefinitions>
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>
            <Label Grid.Row="0" Grid.Column="0"
                   TextColor="Black"
                   Text="Page Title" />
        </Grid>
    </NavigationPage.TitleView>

    <StackLayout>
        <!-- Place new controls here -->
        <Label Text="Welcome to Xamarin.Forms!" 
               HorizontalOptions="Center"
               VerticalOptions="CenterAndExpand" />
    </StackLayout>

</ContentPage>

这是输出...

我还尝试了StackLayout，结果相同...

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             x:Class="SampleApp.MainPage">

    <NavigationPage.TitleView>
        <StackLayout BackgroundColor="Blue" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
            <Label Grid.Row="0" Grid.Column="0"
                   TextColor="Black"
                   Text="Page Title" />
        </StackLayout>
    </NavigationPage.TitleView>

    <StackLayout>
        <!-- Place new controls here -->
        <Label Text="Welcome to Xamarin.Forms!" 
               HorizontalOptions="Center"
               VerticalOptions="CenterAndExpand" />
    </StackLayout>

</ContentPage>

Answer 1

如评论中的Jason所述， NavigationPage.TitleView是Navigation Bar中NavigationPage的一部分。要自定义TitleView，您首先应创建一个NavigationPage：

public App ()
{
  MainPage = new NavigationPage (new Page1());
}

然后在ContentPage中设置TitleView：

<NavigationPage.TitleView>
    <Label Text="Page Title" />
</NavigationPage.TitleView>

引用：Hierarchical Navigation