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javascriptjqueryjquery-mobilemobiletouch

How to detect touchmove length/offsets?


In developer tools I can see that touchmove event is fired multiple times while performing finger move*.

I'm looking for solution that should move div on which touchmove is performed - for exact number of touch move pixels, for either one or both axis.

What have I done so far?

I've tried to bind anonymous function to div's touchmove event, expecting that e argument of anonymous function will have something like offsetX & offsetY like mousemove do, so I could update position parameters of div accordingly.

Something like this:

$('div').on('touchmove', function(e){
  console.log(e);
  //e has no offset or similar param known to me
});

No results.

What should I do instead?

Special appeal: I will upvote any working solution, but accepted answer goes to the one that will give me at least a starting point about what should I do in plain JavaScript, without abstractions like jQuery mobile.

* I'm actually doing cursor touch emulation in Chrome dev tools


Solution

  • I would recommend looking at this article that demonstrates a simple setup for the "touchmove" event and obtaining the offset position in jQuery: http://www.devinrolsen.com/basic-jquery-touchmove-event-setup/

    In case the article disappears, here is the code setup with the offset calculated from the event from the article.

    $('#someElm').bind('touchmove',function(e){
      e.preventDefault();
      var touch = e.originalEvent.touches[0] || e.originalEvent.changedTouches[0];
      var elm = $(this).offset();
      var x = touch.pageX - elm.left;
      var y = touch.pageY - elm.top;
    });
    

    Hopefully this can help find a solution in plain javascript as well.