Re: GWT Support for Touch Event

Craig:

I appreciate your suggestion. Behind the scene I'm handling multiple touches, though only one touch is being considered. The difference between your approach and mine is drawingPaper.addDomHandler and drawingPaper.addHandler. I will give it a try and let you know.

Thank You

--v

On Monday, September 9, 2019 at 4:40:38 AM UTC-4, Craig Mitchell wrote:

I found this as well.  I think browser implementation of these old single touch events isn't great.  I switched to using the multi touch versions.  Something like this:

private HashMap<Integer, Touch> touches;

private void handleScreenTouches(JsArray<Touch> newTouches, boolean touchDown) {

  // Update the touch collection

  for (int i=0; i<newTouches.length(); i++) {

    Touch touch = newTouches.get(i);

    if (touch != null) {

      if (touchDown) {

        touches.put(touch.getIdentifier(), touch);

      }

      else {

        touches.remove(touch.getIdentifier());

      }

    }

  }

  // Look through the remaining touches
  for (Touch touch : touches.values()) {
    ...
  }

}

drawingPaper.addDomHandler(event -> {
    handleScreenTouches(event.getChangedTouches(), true);
}, TouchStartEvent.getType()));


drawingPaper.addDomHandler(event -> {
    handleScreenTouches(event.getChangedTouches(), true);
}, TouchMoveEvent.getType()));


drawingPaper.addDomHandler(event -> {
    handleScreenTouches(event.getChangedTouches(), false);
}, TouchEndEvent.getType()));

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