将本机UIManager.measureInWindow坐标反应为android MotionEvent坐标

Question

I am using a native function that works fine using the coords i get from MotionEvent:

    @Override
    public boolean onTap(MotionEvent e) {

        int x = Math.round(e.getX());
        int y = Math.round(e.getY());
        myFunction(x, y);
    }

What i need to do, is to get the coordinates of a view in react native to be able to use the same java function. For some reason when i use measure view position it seems that x and y are in a different scale than MotionEvent e.getX() and e.getY().

This is the i am using in my React Native component:

UIManager.measureInWindow(findNodeHandle(this.view),
      (x, y, w, h) => {
         this.myNativeComponent.mapDeviceCoordsToPage(x, y);
      });

Answer 1

After doing some reasearch i found the answer in this article . The coordinates returned by UIManager.measureInWindow's callback are layout coordinates. To get the pixel coordinates like MotionEvent you need to use react native's PixelRatio.getPixelSizeForLayoutSize function. So my final solution looks like this:

UIManager.measureInWindow(findNodeHandle(this.view),
  (x, y, w, h) => {
     const pixelX = PixelRatio.getPixelSizeForLayoutSize(x);
     const pixelY = PixelRatio.getPixelSizeForLayoutSize(y);
     this.myNativeComponent.mapDeviceCoordsToPage(pixelX, pixelY);
  });