/**
* We have an issue with Android that makes it pretty much impossible to compose gestures.
* Below is my stab at picking up gestures from the activity - the idea is that the main activity would pass all touches to this method
* the system will work, and will work very richly (with delay touch, cancel touches, delegate callback for should
* recognize in parallel, etc)
* However, my time is limited, so this is crude for now.
*/
public void ProcessGestureMotionEvent(GestureMotionEvent gestureEvent)
{
var ev = gestureEvent.MotionEvent;
//TODO work out if it's our view in here, then update the coordinates
int[] location = new int[2];
NativeView.GetLocationOnScreen(location);
var nativeViewScreenLocation = new Xamarin.Forms.Point(location [0], location [1]);
var offset = Xamarin.Forms.Point.Zero;
var touchPoint = new Xamarin.Forms.Point(ev.GetX(), ev.GetY());
var mainPointerId = ev.GetPointerId(0);
//1. is it inside the view?
Console.WriteLine("touch point {0} view bounds {1} size {2},{3}", touchPoint, nativeViewScreenLocation, NativeView.Width, NativeView.Height);
var isInsideOfView = touchPoint.X >= nativeViewScreenLocation.X && touchPoint.Y >= nativeViewScreenLocation.Y &&
touchPoint.X <= (NativeView.Width + nativeViewScreenLocation.X) && touchPoint.Y <= (NativeView.Height + nativeViewScreenLocation.Y);
//2. report touches inside, or outside but tracked? (so cancels can occur)
//TODO track more touches
if (isInsideOfView || PointerId == mainPointerId)
{
//if letting the view know, translate the coords into local view coords (apply the offsets to the touch)
offset.X = -nativeViewScreenLocation.X;
offset.Y = -nativeViewScreenLocation.Y;
ev.OffsetLocation((float)offset.X, (float)offset.Y);
var offsetLocation = new Xamarin.Forms.Point(ev.GetX(), ev.GetY());
if (isInsideOfView)
{
Console.WriteLine("INSIDE " + ev.Action + " offset " + offset + " results in " + offsetLocation);
}
else
{
Console.WriteLine("touch outside view, but was tracked " + offset);
}
//TODO - ask the view if it's happy to process this touch at the same time as another gesture - I see no way to make it work for views.. (without
//an entire Touch dispatching mechanism:/)
//that will be done by 2 parses - one to discover all *gestures* that want the touch, then another parse to go back through and either cancel
//or pass the touches long
//that's not implemented yet though (time)
ProcessMotionEvent(gestureEvent);
//remove the offset
ev.OffsetLocation((float)-offset.X, (float)-offset.Y);
}
// Console.WriteLine ("location " + ev.GetX () + ", " + ev.GetY () + " offset " + offset);
}
protected Xamarin.Forms.Point GetLocationInAncestorView(Xamarin.Forms.Point location, Xamarin.Forms.VisualElement view)
{
int[] nativeViewLocation = new int[2];
NativeView.GetLocationOnScreen(nativeViewLocation);
var nativeViewLocationOnScreen = new Xamarin.Forms.Point(nativeViewLocation [0], nativeViewLocation [1]);
var offsetLocation = new Xamarin.Forms.Point(location.X + nativeViewLocationOnScreen.X, location.Y + nativeViewLocationOnScreen.Y);
var targetViewRenderer = view.GetRenderer();
var targetView = targetViewRenderer.ViewGroup;
int[] targetViewLocation = new int[2];
targetView.GetLocationOnScreen(targetViewLocation);
var nativeViewScreenLocation = new Xamarin.Forms.Point(targetViewLocation [0], targetViewLocation [1]);
var returnPoint = offsetLocation;
returnPoint.X -= nativeViewScreenLocation.X;
returnPoint.Y -= nativeViewScreenLocation.Y;
// Console.WriteLine ("offsetLocation {0} nativeViewLocationOnScreen {1} returnPoint", offsetLocation, nativeViewLocationOnScreen);
// Console.WriteLine ("location {0} parentViewLoc {1} returnPoint {2}", location, nativeViewScreenLocation, returnPoint);
return(returnPoint);
}
