windows-8 - 触摸时 FlipView 崩溃

Question

在 Windows 应用商店应用程序中

XAML

<Page
    x:Class="FunctionTest.BlankPage1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:FunctionTest"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">
    <Page.Resources>
        <Storyboard x:Name="FloatingFlipOver">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Projection).(PlaneProjection.GlobalOffsetZ)" Storyboard.TargetName="FloatingRoot">
                <EasingDoubleKeyFrame KeyTime="0" Value="-2000"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="0">
                    <EasingDoubleKeyFrame.EasingFunction>
                        <QuarticEase/>
                    </EasingDoubleKeyFrame.EasingFunction>
                </EasingDoubleKeyFrame>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Projection).(PlaneProjection.RotationY)" Storyboard.TargetName="FloatingRoot">
                <EasingDoubleKeyFrame KeyTime="0" Value="180"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="0">
                    <EasingDoubleKeyFrame.EasingFunction>
                        <QuarticEase/>
                    </EasingDoubleKeyFrame.EasingFunction>
                </EasingDoubleKeyFrame>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="FloatingRoot">
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.2" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>
    </Page.Resources>

    <Grid>        
        <Grid x:Name="FloatingRoot" Visibility="Collapsed" Width="500" Height="300">
            <Grid.Projection>
                <PlaneProjection  CenterOfRotationX="0.5" CenterOfRotationY="0.5"/>
            </Grid.Projection>
            <Rectangle x:Name="FloatingBackground" Fill="SkyBlue" />
            <FlipView>
                <Grid x:Name="FloatingContainer" Width="300" Height="300">

                </Grid>
            </FlipView>
        </Grid>
        <Button Content="Test" HorizontalAlignment="Left" Margin="46,36,0,0" VerticalAlignment="Top" Click="Test_Click"/>
    </Grid>
</Page>

代码

private void Test_Click(object sender, RoutedEventArgs e)
{
    Button msiBtn = new Button();
    msiBtn.Content = "addBtn";
    msiBtn.Width = 100; msiBtn.Height = 50;
    msiBtn.Tapped += msiBtn_Tapped;
    FloatingContainer.Children.Add(msiBtn);
    FloatingRoot.Opacity = 0;
    FloatingRoot.Visibility = Visibility.Visible;
    FloatingFlipOver.Begin();
}

void msiBtn_Tapped(object sender, TappedRoutedEventArgs e)
{
    FloatingRoot.Visibility = Visibility.Collapsed;
    FloatingContainer.Children.Clear();
}

这在与鼠标一起使用时有效，
但是当我触摸 FloatingContainer 中添加的按钮时它会崩溃，
有时，即使我触摸 FloatingContainer(不是按钮)，它也会崩溃。
这是一个错误吗？

Answer 1

我想你的意思是崩溃，而不是崩溃，对吧？因为这就是我所看到的。

存在与 ScrollViewers 和投影相关的已知错误。我不确定它是否被公开讨论过，但我在 WinRT XAML 工具包(在 FlipAnimation 中)中听到的一种解决方法似乎对我有用，因为 FlipView 将 ScrollViewer 作为其模板的一部分。基本上，您需要将 ScrollViewer 的 ZoomMode 更改为其他内容然后返回，然后它就可以正常工作而不会崩溃。为了修复代码片段中的代码，我引用了 WinRT XAML 工具包以使用 VisualTreeHelperExtensions 来帮助提取 ScrollViewer 并在动画完成后来回更改 ZoomMode，如下所示:

using WinRTXamlToolkit.Controls.Extensions;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Input;

namespace App96
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }

        private void Test_Click(object sender, RoutedEventArgs e)
        {
            Button msiBtn = new Button();
            msiBtn.Content = "addBtn";
            msiBtn.Width = 100; msiBtn.Height = 50;
            msiBtn.Tapped += msiBtn_Tapped;
            FloatingContainer.Children.Add(msiBtn);
            FloatingRoot.Opacity = 0;
            FloatingRoot.Visibility = Visibility.Visible;
            FloatingFlipOver.Begin();
            FloatingFlipOver.Completed -= FloatingFlipOver_Completed;
            FloatingFlipOver.Completed += FloatingFlipOver_Completed;
        }

        void FloatingFlipOver_Completed(object sender, object e)
        {
            foreach (var sv in FloatingRoot.GetDescendantsOfType<ScrollViewer>())
            {
                sv.ZoomMode = (ZoomMode)(((int)sv.ZoomMode + 1) % 2);
                sv.ZoomMode = (ZoomMode)(((int)sv.ZoomMode + 1) % 2);
            }
        }

        void msiBtn_Tapped(object sender, TappedRoutedEventArgs e)
        {
            FloatingRoot.Visibility = Visibility.Collapsed;
            FloatingContainer.Children.Clear();
        }
    }
}

如果您不想要整个 Toolkit，可以使用 VisualTreeHelperExtensions 的相关位:

public static class VisualTreeHelperExtensions
{
    public static IEnumerable<T> GetDescendantsOfType<T>(this DependencyObject start) where T : DependencyObject
    {
        return start.GetDescendants().OfType<T>();
    }

    public static IEnumerable<DependencyObject> GetDescendants(this DependencyObject start)
    {
        var queue = new Queue<DependencyObject>();
        var count = VisualTreeHelper.GetChildrenCount(start);

        for (int i = 0; i < count; i++)
        {
            var child = VisualTreeHelper.GetChild(start, i);
            yield return child;
            queue.Enqueue(child);
        }

        while (queue.Count > 0)
        {
            var parent = queue.Dequeue();
            var count2 = VisualTreeHelper.GetChildrenCount(parent);

            for (int i = 0; i < count2; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                yield return child;
                queue.Enqueue(child);
            }
        }
    }
}