javascript - 触摸事件不返回触摸数据

Question

编辑:“这不能在 Angular UI 模式中完成”是一个有效的答案，如果确实如此的话。

这是我从触摸事件中获得的返回数据。明显缺少任何有用的触摸 X/Y 坐标 (https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/changedTouches)。这是一个无可救药的通用问题，但是，有什么想法吗？传递给触摸时执行的函数的“事件”对象:

{
      "originalEvent": {
        "isTrusted": true
      },
      "type": "touchstart",
      "timeStamp": 1450388006795,
      "jQuery203026962137850932777": true,
      "which": 0,
      "view": "$WINDOW",
      "target": {},
      "shiftKey": false,
      "metaKey": false,
      "eventPhase": 3,
      "currentTarget": {},
      "ctrlKey": false,
      "cancelable": true,
      "bubbles": true,
      "altKey": false,
      "delegateTarget": {},
      "handleObj": {
        "type": "touchstart",
        "origType": "touchstart",
        "data": null,
        "guid": 2026,
        "namespace": ""
      },
      "data": null
    }

现在，这是在 Canvas 中的 Angular UI 模式中，但鼠标事件工作正常。顺便说一句，这是我的元素:

link: function(scope, element, attrs, model){
                //scope.canvasElem = element[0].children[0].children[0];
                scope.canvasElem = angular.element($('.touchScreen'))[0];
                scope.ctx = scope.canvasElem.getContext('2d');

这是我如何绑定(bind)的示例:

element.bind('touchstart', scope.touchStart);

编辑，这里有一个mousedown事件对象用于对比:

{
  "originalEvent": {
    "isTrusted": true
  },
  "type": "mousedown",
  "timeStamp": 1450389131400,
  "jQuery20309114612976554781": true,
  "toElement": {},
  "screenY": 436,
  "screenX": 726,
  "pageY": 375,
  "pageX": 726,
  "offsetY": 81,
  "offsetX": 41,
  "clientY": 375,
  "clientX": 726,
  "buttons": 1,
  "button": 0,
  "which": 1,
  "view": "$WINDOW",
  "target": {},
  "shiftKey": false,
  "relatedTarget": null,
  "metaKey": false,
  "eventPhase": 3,
  "currentTarget": {},
  "ctrlKey": false,
  "cancelable": true,
  "bubbles": true,
  "altKey": false,
  "delegateTarget": {},
  "handleObj": {
    "type": "mousedown",
    "origType": "mousedown",
    "data": null,
    "guid": 2025,
    "namespace": ""
  },
  "data": null
}

Answer 1

例如你可以使用指令绑定(bind)触摸事件，在指令中可以有这样的代码，

element.on('touchstart', function (event) {
     event = event.originalEvent || event;
     //actions
     event.stopPropagation();   //if you need stop the propagation of the event
});

还需要根据您的目标注意 4 种类型的触摸事件(touchstart、touchend、touchmove、touchcancel)的行为。 对于捕获光标使用的位置，

element.on('touchmove', function (event) {
    event.preventDefault();
    if (event.targetTouches.length == 1) {  //when only has one target in touch
         var touch = event.targetTouches[0];
        // Place element where the finger is
        var x = touch.pageX + 'px';
        var y = touch.pageY + 'px';
    }
    event.stopPropagation();
});