如何启用滑动手势以在 Xamarin 表单 UWP 中显示母版页？答案

【问题标题】：How to enable swipe gesture to bring master page in Xamarin forms UWP?如何启用滑动手势以在 Xamarin 表单 UWP 中显示母版页？
【发布时间】：2017-12-24 09:05:22
【问题描述】：

我有一个带有 iOS 和 UWP 的 Xamarin 表单项目，已经实现了主从布局，它在两个平台上都运行良好，但在 iOS 上，如果我们从左侧滑动，将显示母版页（汉堡菜单），但在UWP我们需要点击菜单图标调出母版页，如何在UWP上启用滑动显示母版页？

【问题讨论】：

标签： ios uwp xamarin.forms

【解决方案1】：

目前，Xamarin.Forms 没有这样的“SwipeGestureRecognizer”api。但是您可以基于PanGestureRecognizer 自定义SwipeGestureRecognizer。我编写了以下代码来模拟“SwipeGestureRecognizer”。但我使用的阈值仅用于测试，并非真实阈值，您可以根据需要修改阈值。

public enum SwipeDeriction
{
    Left = 0,
    Rigth,
    Above,
    Bottom
}

public class SwipeGestureReconginzer : PanGestureRecognizer
{
    public delegate void SwipeRequedt(object sender, SwipeDerrictionEventArgs e);

    public event EventHandler<SwipeDerrictionEventArgs> Swiped;

    public SwipeGestureReconginzer()
    {
        this.PanUpdated += SwipeGestureReconginzer_PanUpdated;
    }

    private void SwipeGestureReconginzer_PanUpdated(object sender, PanUpdatedEventArgs e)
    {
        if (e.TotalY > -5 | e.TotalY < 5)
        {
            if (e.TotalX > 10)
            {
                Swiped(this, new SwipeDerrictionEventArgs(SwipeDeriction.Rigth));
            }
            if (e.TotalX < -10)
            {
                Swiped(this, new SwipeDerrictionEventArgs(SwipeDeriction.Left));
            }
        }

        if (e.TotalX > -5 | e.TotalX < 5)
        {
            if (e.TotalY > 10)
            {
                Swiped(this, new SwipeDerrictionEventArgs(SwipeDeriction.Bottom));
            }
            if (e.TotalY < -10)
            {
                Swiped(this, new SwipeDerrictionEventArgs(SwipeDeriction.Above));
            }
        }
    }
}

public class SwipeDerrictionEventArgs : EventArgs
{
    public SwipeDeriction Deriction { get; }

    public SwipeDerrictionEventArgs(SwipeDeriction deriction)
    {
        Deriction = deriction;
    }
}

MainPage.xaml.cs

var swipe = new SwipeGestureReconginzer();
swipe.Swiped += Tee_Swiped;
TestLabel.GestureRecognizers.Add(swipe);

private void Tee_Swiped(object sender, SwipeDerrictionEventArgs e)
{
    switch (e.Deriction)
      {
          case SwipeDeriction.Above:
              {
              }
              break;

          case SwipeDeriction.Left:
              {
              }
              break;

          case SwipeDeriction.Rigth:
              {
              }
              break;

          case SwipeDeriction.Bottom:
              {
              }
              break;

          default:
              break;
     }
}

【讨论】：