Judgment of single touch and double touch with Skiasharp

Question

For example, if there is a code that judges single touch and multi-touch, each judgment can be made, but even if multi-touch is performed, the multi-touch command is executed after the single-touch command is executed. May be done.
Is there a reliable way to do single touch and multi touch respectively?

Dictionary<long, SKPoint> dragDictionary = new Dictionary<long, SKPoint>();

    private void OnTouch(object sender, SKTouchEventArgs e)
    {
        switch (e.ActionType)
        {
            case SKTouchAction.Pressed:
                dragDictionary[e.Id] = e.Location;
                break;
            case SKTouchAction.Entered:
                break;
            case SKTouchAction.Moved:
                if (dragDictionary.Keys.Count > 1)
                {
                    dragDictionary[e.Id] = e.Location;
                    SKPoint? p1 = null;
                    SKPoint? p2 = null;
                    foreach (long key in dragDictionary.Keys)
                    {
                        if (p1 == null)
                        {
                            p1 = dragDictionary[key];
                        }
                        else if (p2 == null)
                        {
                            p2 = dragDictionary[key];
                        }
                    }
                    //MultiTouch handle
                }
                else
                {
                    //SingleTouch handle
                }
                break;
            case SKTouchAction.Released:
                dragDictionary.Remove(e.Id);
                break;
            case SKTouchAction.Exited:
                break;
        }
        // we have handled these events
        e.Handled = true;
        ((SKCanvasView)sender).InvalidateSurface();
    }

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

If you judge single tap or double tap in SKTouchAction.Moved tag, your finger cannot left your screen, it will not work for double tap.

So, you can hanle the single tap or double tap in SKTouchAction.Pressed: like following code.

   private static int clickCount;  
           private static object _sender;  
             
          // Dictionary<long, SKPoint> dragDictionary = new Dictionary<long, SKPoint>();  
           private void CanvasView_Touch(object sender, SKTouchEventArgs e)  
           {  
     
               // throw new System.NotImplementedException();  
                
               switch (e.ActionType)  
               {  
                   case SKTouchAction.Pressed:  
                       
     
     
                       if (clickCount < 1)  
                       {  
                           TimeSpan tt = new TimeSpan(0, 0, 0, 0, 250);  
                           _sender = sender;  
                           Device.StartTimer(tt, ClickHandle);  
                       }  
                       clickCount++;  
     
                       break;  
                       
                   case SKTouchAction.Entered:  
     
                      // Console.WriteLine("======================Entered================");  
                       break;  
                   case SKTouchAction.Moved:  
     
                       // Console.WriteLine("======================Moved================");  
                       //if (dragDictionary.Keys.Count > 1)  
                       //{  
                       //    dragDictionary[e.Id] = e.Location;  
                       //    SKPoint? p1 = null;  
                       //    SKPoint? p2 = null;  
                       //    foreach (long key in dragDictionary.Keys)  
                       //    {  
                       //        if (p1 == null)  
                       //        {  
                       //            p1 = dragDictionary[key];  
                       //        }  
                       //        else if (p2 == null)  
                       //        {  
                       //            p2 = dragDictionary[key];  
                       //        }  
                       //    }  
                       //    //MultiTouch handle  
     
                       //    Console.WriteLine("======================DOUBLE TAP================");  
                       //}  
                       //else  
                       //{  
                       //    //SingleTouch handle  
     
                       //    Console.WriteLine("======================SINGLE  TAP================");  
                       //}  
                       break;  
                   case SKTouchAction.Released:  
                       // dragDictionary.Remove(e.Id);  
     
                     
                       break;  
                   case SKTouchAction.Exited:  
     
                      
                       break;  
               }  
               // we have handled these events  
               e.Handled = true;  
               ((SKCanvasView)sender).InvalidateSurface();  
           }  
     
           private bool ClickHandle()  
           {  
               if (clickCount > 1)  
               {  
                    
                   DisplayAlert("info", "DOUBLE TAP","Ok");  
                  
               }  
               else  
               {  
                    
                   DisplayAlert("info", "single TAP", "Ok");  
                 
               }  
               clickCount = 0;  
               _sender = null;  
               return false;  
           }  

Best Regards,

Leon Lu

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