Maui android 捏合手势容器问题

Question

你好

 

我使用 Ver 17.10 preview 1 和 Android Ver 34。

 

我尝试添加捏合手势容器，但收到错误消息。

 

如下：

//Error I get
//MainPage.xaml : XamlC error : Failed to resolve assembly: 'PinchGesture, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'
// File
// MainPage.xml
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="
http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="
http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="RazKmoShed.MainPage" Loaded="MainPage_Loaded" x:Name="myContentPage"
             xmlns:mct="
http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
             xmlns:local="clr-namespace:RazKmoShed;assembly=PinchGesture"
             xmlns:label="clr-namespace:RazKmoShed"
             xmlns:entry="clr-namespace:RazKmoShed"
             FlowDirection="LeftToRight" BackgroundColor="#ECE5DD"  >
<ScrollView x:Name="topscroll" HorizontalScrollBarVisibility="Never" VerticalScrollBarVisibility="Never" >
<local:PinchToZoomContainer>
<VerticalStackLayout x:Name="vLayout" Margin="10" Padding="5" Spacing="5" BackgroundColor="#ECE5DD" >
   . . . . . . . . ...
</VerticalStackLayout>
</local:PinchToZoomContainer>
</ScrollView>
</ContentPage>
// File
// PinchToZoomContainer.cs 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace RazKmoShed
{
  public class PinchToZoomContainer : ContentView
  {
    double currentScale = 1;
    double startScale = 1;
    double xOffset = 0;
    double yOffset = 0;
    public PinchToZoomContainer()
    {
        PinchGestureRecognizer pinchGesture = new PinchGestureRecognizer();
        pinchGesture.PinchUpdated += OnPinchUpdated;
        GestureRecognizers.Add(pinchGesture);
    }
    void OnPinchUpdated(object sender, PinchGestureUpdatedEventArgs e)
    {
        if (e.Status == GestureStatus.Started)
        {
            // Store the current scale factor applied to the wrapped user interface element,
            // and zero the components for the center point of the translate transform.
            startScale = Content.Scale;
            Content.AnchorX = 0;
            Content.AnchorY = 0;
        }
        if (e.Status == GestureStatus.Running)
        {
            // Calculate the scale factor to be applied.
            currentScale += (e.Scale - 1) * startScale;
            currentScale = Math.Max(1, currentScale);
            // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
            // so get the X pixel coordinate.
            double renderedX = Content.X + xOffset;
            double deltaX = renderedX / Width;
            double deltaWidth = Width / (Content.Width * startScale);
            double originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;
            // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
            // so get the Y pixel coordinate.
            double renderedY = Content.Y + yOffset;
            double deltaY = renderedY / Height;
            double deltaHeight = Height / (Content.Height * startScale);
            double originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;
            // Calculate the transformed element pixel coordinates.
            double targetX = xOffset - (originX * Content.Width) * (currentScale - startScale);
            double targetY = yOffset - (originY * Content.Height) * (currentScale - startScale);
            // Apply translation based on the change in origin.
            Content.TranslationX = Math.Clamp(targetX, -Content.Width * (currentScale - 1), 0);
            Content.TranslationY = Math.Clamp(targetY, -Content.Height * (currentScale - 1), 0);
            // Apply scale factor
            Content.Scale = currentScale;
        }
        if (e.Status == GestureStatus.Completed)
        {
            // Store the translation delta's of the wrapped user interface element.
            xOffset = Content.TranslationX;
            yOffset = Content.TranslationY;
        }
    }
  }
}

 

我需要做什么? 请帮助我。谢谢。

 

 

 

此问题整理于：https://learn.microsoft.com/en-us/answers/questions/1634481/maui-for-android-pinch-gesture-container-issue

Answer 1

你好，

 

此错误是由 assembly=PinchGesture 引起的。

 

根据 XAML Namespaces and Namespace Mapping - WPF .NET Framework | Microsoft Learn 文档中的说明，此属性通常指向 dll 或其他扩展文件。

 

assembly= The assembly that contains some or all of the referenced CLR namespace. This value is typically just the name of the assembly, not the path, and does not include the extension (such as .dll or .exe). The path to that assembly must be established as a project reference in the project file that contains the XAML you are trying to map. In order to incorporate versioning and strong-name signing, the assembly value can be a string as defined by AssemblyName, rather than the simple string name.

 

解决方法 1：

 

将 xmlns:local="clr-namespace:RazKmoShed;assembly=PinchGesture" 修改为 xmlns:local="clr-namespace:RazKmoShed"

 

解决方法 2：

 

将 xmlns:local="clr-namespace:RazKmoShed;assembly=PinchGesture" 修改为 xmlns:local="clr-namespace:RazKmoShed;assembly=RazKmoShed"

 

 

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