Made tap events on mobile less sensitive to touch moves. closes #1111

CHANGELOG.md

@@ -13,6 +13,7 @@ CHANGELOG
 * Added a more informative and styled fallback message for non-html5 browsers [[view](https://github.com/videojs/video.js/pull/1181)]
 * Added the option to provide an array of child components instead of an object [[view](https://github.com/videojs/video.js/pull/1093)]
 * Fixed casing on webkitRequestFullscreen [[view](https://github.com/videojs/video.js/pull/1101)]
+* Made tap events on mobile less sensitive to touch moves [[view](https://github.com/videojs/video.js/pull/1111)]
 
 --------------------
 

src/js/button.js

@@ -15,23 +15,9 @@ vjs.Button = vjs.Component.extend({
   init: function(player, options){
     vjs.Component.call(this, player, options);
 
-    var touchstart = false;
-    this.on('touchstart', function(event) {
-      // Stop click and other mouse events from triggering also
-      event.preventDefault();
-      touchstart = true;
-    });
-    this.on('touchmove', function() {
-      touchstart = false;
-    });
-    var self = this;
-    this.on('touchend', function(event) {
-      if (touchstart) {
-        self.onClick(event);
-      }
-      event.preventDefault();
-    });
+    this.emitTapEvents();
 
+    this.on('tap', this.onClick);
     this.on('click', this.onClick);
     this.on('focus', this.onFocus);
     this.on('blur', this.onBlur);

src/js/component.js

@@ -864,35 +864,61 @@ vjs.Component.prototype.onResize;
  * @private
  */
 vjs.Component.prototype.emitTapEvents = function(){
-  var touchStart, touchTime, couldBeTap, noTap;
+  var touchStart, firstTouch, touchTime, couldBeTap, noTap,
+      xdiff, ydiff, touchDistance, tapMovementThreshold;
 
   // Track the start time so we can determine how long the touch lasted
   touchStart = 0;
+  firstTouch = null;
+
+  // Maximum movement allowed during a touch event to still be considered a tap
+  tapMovementThreshold = 22;
 
   this.on('touchstart', function(event) {
-    // Record start time so we can detect a tap vs. "touch and hold"
-    touchStart = new Date().getTime();
-    // Reset couldBeTap tracking
-    couldBeTap = true;
+    // If more than one finger, don't consider treating this as a click
+    if (event.touches.length === 1) {
+      firstTouch = event.touches[0];
+      // Record start time so we can detect a tap vs. "touch and hold"
+      touchStart = new Date().getTime();
+      // Reset couldBeTap tracking
+      couldBeTap = true;
+    }
+  });
+
+  this.on('touchmove', function(event) {
+    // If more than one finger, don't consider treating this as a click
+    if (event.touches.length > 1) {
+      couldBeTap = false;
+    } else if (firstTouch) {
+      // Some devices will throw touchmoves for all but the slightest of taps.
+      // So, if we moved only a small distance, this could still be a tap
+      xdiff = event.touches[0].pageX - firstTouch.pageX;
+      ydiff = event.touches[0].pageY - firstTouch.pageY;
+      touchDistance = Math.sqrt(xdiff * xdiff + ydiff * ydiff);
+      if (touchDistance > tapMovementThreshold) {
+        couldBeTap = false;
+      }
+    }
   });
 
   noTap = function(){
     couldBeTap = false;
   };
   // TODO: Listen to the original target. http://youtu.be/DujfpXOKUp8?t=13m8s
-  this.on('touchmove', noTap);
   this.on('touchleave', noTap);
   this.on('touchcancel', noTap);
 
   // When the touch ends, measure how long it took and trigger the appropriate
   // event
   this.on('touchend', function(event) {
+    firstTouch = null;
     // Proceed only if the touchmove/leave/cancel event didn't happen
     if (couldBeTap === true) {
       // Measure how long the touch lasted
       touchTime = new Date().getTime() - touchStart;
       // The touch needs to be quick in order to consider it a tap
       if (touchTime < 250) {
+        event.preventDefault(); // Don't let browser turn this into a click
         this.trigger('tap');
         // It may be good to copy the touchend event object and change the
         // type to tap, if the other event properties aren't exact after

test/unit/component.js

@@ -255,7 +255,7 @@ test('should use a defined content el for appending children', function(){
 });
 
 test('should emit a tap event', function(){
-  expect(1);
+  expect(2);
 
   // Fake touch support. Real touch support isn't needed for this test.
   var origTouch = vjs.TOUCH_ENABLED;
@@ -267,13 +267,27 @@ test('should emit a tap event', function(){
   comp.on('tap', function(){
     ok(true, 'Tap event emitted');
   });
-  comp.trigger('touchstart');
+
+  // A touchstart followed by touchend should trigger a tap
+  vjs.trigger(comp.el(), {type: 'touchstart', touches: [{}]});
   comp.trigger('touchend');
 
-  // This second test should not trigger another tap event because
-  // a touchmove is happening
-  comp.trigger('touchstart');
-  comp.trigger('touchmove');
+  // A touchmove with a lot of movement should not trigger a tap
+  vjs.trigger(comp.el(), {type: 'touchstart', touches: [
+    { pageX: 0, pageY: 0 }
+  ]});
+  vjs.trigger(comp.el(), {type: 'touchmove', touches: [
+    { pageX: 100, pageY: 100 }
+  ]});
+  comp.trigger('touchend');
+
+  // A touchmove with not much movement should still allow a tap
+  vjs.trigger(comp.el(), {type: 'touchstart', touches: [
+    { pageX: 0, pageY: 0 }
+  ]});
+  vjs.trigger(comp.el(), {type: 'touchmove', touches: [
+    { pageX: 10, pageY: 10 }
+  ]});
   comp.trigger('touchend');
 
   // Reset to orignial value