Windows Phone 7 开发探索笔记3——触控操作之GestureListener

上篇文章介绍了Silverlight for Windows Phone中的高级触控编程接口，本文将讲解Silverlight for Windows Phone Toolkit中的GestureListener对象。有了上篇文章的铺垫，再来看GestureListener的相关操作就很容易了。

一．Silverlight for Windows Phone Toolkit

Silverlight for Windows Phone Toolkit为Windows Phone提供了很多方便易用的控件，我们可以通过上面的地址下载后进行安装，下面是安装过程的截图：

装好后，需要在项目中添加程序集的引用，如下图：

然后在Code-Behind文件中添加相应的名称空间：

using Microsoft.Phone.Controls;

在XAML代码中添加xmlns：

xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit"

二．使用GestureListener

注意GestureListener是在XAML元素上应用的，所以要使用 GestureListener，首先要在那个元素中添加<GestureService.GestureListener>对象，然后再为我们要监听的手势添加事件处理程序。由于是在XAML元素中应用，所以手势只有在被应用到的那个元素中才能被识别。GestureListener支持以下手势：

Tap
DoubleTap
Hold
Flick
Pinch
Drag and Drop

我使用了上篇文章中那个程序的UI，来看一下程序的Logic Tree和效果图：

我对这个矩形添加了以下手势的监听：

代码

在Code-Behind文件中的事件处理程序如下：

代码

using System;
using System.Diagnostics;
using System.Windows;
using System.Windows.Media;
using Microsoft.Phone.Controls;

namespace WindowsPhoneGestureListenerDemo
{
    public partial class MainPage : PhoneApplicationPage
    {
        Random rand = new Random();

        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }

        private void GestureListener_Tap(object sender, GestureEventArgs e)
        {
            if (e.OriginalSource == rectangle)
            {
                rectangle.Fill = new SolidColorBrush(
                            Color.FromArgb(255, (byte)rand.Next(256),
                                                (byte)rand.Next(256),
                                                (byte)rand.Next(256)));
            }
            var position = e.GetPosition(rectangle);
            Debug.WriteLine("Tap\n");
        }

        private void GestureListener_DoubleTap(object sender, GestureEventArgs e)
        {
            translation.X = translation.Y = 0;
            Debug.WriteLine("DoubleTap\n");
        }

        private void GestureListener_Flick(object sender, FlickGestureEventArgs e)
        {
            Debug.WriteLine("Flick");
            Debug.WriteLine("Angle: " + e.Angle);
            Debug.WriteLine("Direction: " + e.Direction.ToString());
            Debug.WriteLine("HorizontalVelocity(X): " + e.HorizontalVelocity.ToString() + " VerticalVelocity(Y):" + e.VerticalVelocity.ToString() + "\n");
        }

        private void GestureListener_Hold(object sender, GestureEventArgs e)
        {
            Debug.WriteLine("Hold\n");
            MessageBox.Show("You are holding the rectangle!", "Hold", MessageBoxButton.OK);
        }

        private void GestureListener_GestureBegin(object sender, GestureEventArgs e)
        {
            var position = e.GetPosition(rectangle);
            Debug.WriteLine("GestureBegin");
            Debug.WriteLine("GestureBegin Point: X:" + position.X + " Y:" + position.Y + "\n");
        }

        private void GestureListener_GestureCompleted(object sender, GestureEventArgs e)
        {
            var position = e.GetPosition(rectangle);
            Debug.WriteLine("GestureCompleted");
            Debug.WriteLine("GestureCompleted Point: X:" + position.X + " Y:" + position.Y + "\n");
        }

        private void GestureListener_DragStarted(object sender, DragStartedGestureEventArgs e)
        {
            Debug.WriteLine("DragStarted");
            Debug.WriteLine("Direction: " + e.Direction.ToString() + "\n");
        }

        private void GestureListener_DragDelta(object sender, DragDeltaGestureEventArgs e)
        {
            this.translation.X += e.HorizontalChange;
            this.translation.Y += e.VerticalChange;
            Debug.WriteLine("DragDelta");
            Debug.WriteLine("Direction: " + e.Direction.ToString());
            Debug.WriteLine("Change: " + "X: " + e.HorizontalChange.ToString() + " Y: " + e.VerticalChange + "\n");
        }

        private void GestureListener_DragCompleted(object sender, DragCompletedGestureEventArgs e)
        {
            Debug.WriteLine("DragCompleted");
            Debug.WriteLine("Direction: " + e.Direction.ToString());
            Debug.WriteLine("HorizontalChange(X): " + e.HorizontalChange.ToString() + " VerticalChange(Y): " + e.VerticalChange);
            Debug.WriteLine("HorizontalVelocity(X): " + e.HorizontalVelocity.ToString() + " VerticalVelocity(Y):" + e.VerticalVelocity.ToString() + "\n");
        }
    }
}

这些事件使用起来非常方便。GestureBegin和GestureCompleted类似于上一篇文章中的ManipulationStarted和ManipulationCompleted，与Manipulation事件最为相似的尤属Drag事件了。

在单击（Tap）时，矩形的颜色会随机变化，输出如下：