背景：
在移动端，本人要实现对某个元素的拖动，想到使用 jQuery UI 的 draggable 功能。但是发现此插件的拖动只支持PC端，不支持移动端。
原因：
原始的 jQuery UI 里，都是mousedown、mousemove、mouseup来描述拖拽和鼠标的点击事件，而在移动端里，肯定要新添touchstart、touchmove、touchend来描述拖拽和手指的点击事件
实现 demo：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0;" name="viewport">
<title>jQuery UI draggable 适配移动端</title>
</head>
<body>
<img id="img" src="http://placehold.it/200x100"> <script src="//cdn.bootcss.com/jquery/3.0.0-beta1/jquery.js"></script>
<script src="//cdn.bootcss.com/jqueryui/1.11.4/jquery-ui.min.js"></script>
<script> // jQuery UI draggable 适配移动端 var moveFlag = 0; // 是否移动的flag
// /iPad|iPhone|Android/.test( navigator.userAgent ) &&
(function ($) {
var proto = $.ui.mouse.prototype, _mouseInit = proto._mouseInit;
$.extend(proto, {
_mouseInit: function () {
this.element.bind("touchstart." + this.widgetName, $.proxy(this, "_touchStart"));
_mouseInit.apply(this, arguments);
}, _touchStart: function (event) {
this.element.bind("touchmove." + this.widgetName, $.proxy(this, "_touchMove")).bind("touchend." + this.widgetName, $.proxy(this, "_touchEnd"));
this._modifyEvent(event);
$(document).trigger($.Event("mouseup"));
//reset mouseHandled flag in ui.mouse
this._mouseDown(event);
//console.log(this);
//return false; //--------------------touchStart do something--------------------
console.log("i touchStart!"); }, _touchMove: function (event) {
moveFlag = 1;
this._modifyEvent(event);
this._mouseMove(event); //--------------------touchMove do something--------------------
console.log("i touchMove!"); }, _touchEnd: function (event) {
// 主动触发点击事件
if (moveFlag == 0) {
var evt = document.createEvent('Event');
evt.initEvent('click', true, true);
this.handleElement[0].dispatchEvent(evt);
}
this.element.unbind("touchmove." + this.widgetName).unbind("touchend." + this.widgetName);
this._mouseUp(event);
moveFlag = 0; //--------------------touchEnd do something--------------------
console.log("i touchEnd!"); }, _modifyEvent: function (event) {
event.which = 1;
var target = event.originalEvent.targetTouches[0];
event.pageX = target.clientX;
event.pageY = target.clientY;
}
});
})(jQuery); </script>
<script>
// my js
$("#img").draggable();
</script>
</body>
</html>
参考资料：