在Xamarin Forms中爲Windows Phone（8.1和10）平臺刷卡手勢識別器

Question

如何在Xamarin Forms for Windows Phone（8.1 & 10）平臺中最佳實現刷卡gesture recognizer？

我在renderers的Android和iOS平臺上看到很多例子。但不適用於WinRT或UWP。

Answer 1

我看到很多適用於Android和iOS平臺的渲染器的示例。但不適用於WinRT或UWP。

目前，Xamarin.Forms沒有這樣的「SwipeGestureRecognizer」api。但你可以根據PanGestureRecognizer定製SwipeGestureRecognizer。我編寫了下面的代碼來模擬「SwipeGestureRecognizer」。但是我使用的閾值僅用於測試，而不是真實的閾值，您可以根據您的要求修改閾值。

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中

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; 
     } 
    }