public override void TouchesEnded(NSSet touches, UIEvent evt)
{
base.TouchesEnded(touches, evt);
foreach (UITouch touch in touches.Cast <UITouch>())
{
// Get polyline from dictionary and remove it from dictionary
FingerPaintPolyline polyline = inProgressPolylines[touch.Handle];
inProgressPolylines.Remove(touch.Handle);
// Add final point to path and save with completed polylines
polyline.Path.AddLineToPoint(touch.LocationInView(this));
completedPolylines.Add(polyline);
}
SetNeedsDisplay();
}
public override void TouchesBegan(NSSet touches, UIEvent evt)
{
base.TouchesBegan(touches, evt);
foreach (UITouch touch in touches.Cast <UITouch>())
{
// Create a FingerPaintPolyline, set the initial point, and store it
FingerPaintPolyline polyline = new FingerPaintPolyline
{
Color = StrokeColor,
StrokeWidth = StrokeWidth,
};
polyline.Path.MoveToPoint(touch.LocationInView(this));
inProgressPolylines.Add(touch.Handle, polyline);
}
SetNeedsDisplay();
}
// Overrides
public override bool OnTouchEvent(MotionEvent args)
{
// Get the pointer index
int pointerIndex = args.ActionIndex;
// Get the id to identify a finger over the course of its progress
int id = args.GetPointerId(pointerIndex);
// Use ActionMasked here rather than Action to reduce the number of possibilities
switch (args.ActionMasked)
{
case MotionEventActions.Down:
case MotionEventActions.PointerDown:
// Create a Polyline, set the initial point, and store it
FingerPaintPolyline polyline = new FingerPaintPolyline
{
Color = StrokeColor,
StrokeWidth = StrokeWidth
};
polyline.Path.MoveTo(args.GetX(pointerIndex),
args.GetY(pointerIndex));
inProgressPolylines.Add(id, polyline);
break;
case MotionEventActions.Move:
// Multiple Move events are bundled, so handle them differently
for (pointerIndex = 0; pointerIndex < args.PointerCount; pointerIndex++)
{
id = args.GetPointerId(pointerIndex);
inProgressPolylines[id].Path.LineTo(args.GetX(pointerIndex),
args.GetY(pointerIndex));
}
break;
case MotionEventActions.Up:
case MotionEventActions.Pointer1Up:
inProgressPolylines[id].Path.LineTo(args.GetX(pointerIndex),
args.GetY(pointerIndex));
// Transfer the in-progress polyline to a completed polyline
completedPolylines.Add(inProgressPolylines[id]);
inProgressPolylines.Remove(id);
break;
case MotionEventActions.Cancel:
inProgressPolylines.Remove(id);
break;
}
// Invalidate to update the view
Invalidate();
// Request continued touch input
return(true);
}