移动端touch模块

在自己写touch事件时，总是会出现各种各样的bug，正好发现zepto的touch模块，很好用，而且由于zepto和jquery语法的相似性，这个模块也可以直接引用到jquery中，

得花时间好好消化一番，这样以后自己就可以随心所欲了。。。

var touch = {},
touchTimeout, tapTimeout, swipeTimeout, longTapTimeout,
longTapDelay = 750,
gesture

function swipeDirection(x1, x2, y1, y2) { //判定滑动方向
return Math.abs(x1 - x2) >=
Math.abs(y1 - y2) ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
}

function longTap() { //长按
longTapTimeout = null
if (touch.last) {
touch.el.trigger('longTap')
touch = {} 
}
}

function cancelLongTap() { //取消长按
if (longTapTimeout) clearTimeout(longTapTimeout)
longTapTimeout = null
}

function cancelAll() { //取消全部
if (touchTimeout) clearTimeout(touchTimeout)
if (tapTimeout) clearTimeout(tapTimeout)
if (swipeTimeout) clearTimeout(swipeTimeout)
if (longTapTimeout) clearTimeout(longTapTimeout)
touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null
touch = {}
}

function isPrimaryTouch(event){
return (event.pointerType == 'touch' ||
event.pointerType == event.MSPOINTER_TYPE_TOUCH)
&& event.isPrimary
}

function isPointerEventType(e, type){
return (e.type == 'pointer'+type ||
e.type.toLowerCase() == 'mspointer'+type)
}

$(document).ready(function(){
var now, delta, deltaX = 0, deltaY = 0, firstTouch, _isPointerType

if ('MSGesture' in window) {//IE10中新加入的对高级用户输入的识别支持
gesture = new MSGesture() //实例手势对象
gesture.target = document.body
}

$(document)
.bind('MSGestureEnd', function(e){ //类似mouseup，兼容触屏和鼠标操作
var swipeDirectionFromVelocity =
e.velocityX > 1 ? 'Right' : e.velocityX < -1 ? 'Left' : e.velocityY > 1 ? 'Down' : e.velocityY < -1 ? 'Up' : null;
if (swipeDirectionFromVelocity) {
touch.el.trigger('swipe')
touch.el.trigger('swipe'+ swipeDirectionFromVelocity)
}
})
.on('touchstart MSPointerDown pointerdown', function(e){
if((_isPointerType = isPointerEventType(e, 'down')) &&
!isPrimaryTouch(e)) return
firstTouch = _isPointerType ? e : e.touches[0]
if (e.touches && e.touches.length === 1 && touch.x2) {
// Clear out touch movement data if we have it sticking around
// This can occur if touchcancel doesn't fire due to preventDefault, etc.
touch.x2 = undefined
touch.y2 = undefined
}
now = Date.now()
delta = now - (touch.last || now)
touch.el = $('tagName' in firstTouch.target ?
firstTouch.target : firstTouch.target.parentNode)
touchTimeout && clearTimeout(touchTimeout)
touch.x1 = firstTouch.pageX
touch.y1 = firstTouch.pageY
if (delta > 0 && delta <= 250) touch.isDoubleTap = true
touch.last = now
longTapTimeout = setTimeout(longTap, longTapDelay)
// adds the current touch contact for IE gesture recognition
if (gesture && _isPointerType) gesture.addPointer(e.pointerId);
})
.on('touchmove MSPointerMove pointermove', function(e){
if((_isPointerType = isPointerEventType(e, 'move')) &&
!isPrimaryTouch(e)) return
firstTouch = _isPointerType ? e : e.touches[0]
cancelLongTap()
touch.x2 = firstTouch.pageX
touch.y2 = firstTouch.pageY

deltaX += Math.abs(touch.x1 - touch.x2)
deltaY += Math.abs(touch.y1 - touch.y2)
})
.on('touchend MSPointerUp pointerup', function(e){
if((_isPointerType = isPointerEventType(e, 'up')) &&
!isPrimaryTouch(e)) return
cancelLongTap()

// swipe
if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
(touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

swipeTimeout = setTimeout(function() {
touch.el.trigger('swipe')
touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
touch = {}
}, 0)

// normal tap
else if ('last' in touch)
// don't fire tap when delta position changed by more than 30 pixels,
// for instance when moving to a point and back to origin
if (deltaX < 30 && deltaY < 30) {
// delay by one tick so we can cancel the 'tap' event if 'scroll' fires
// ('tap' fires before 'scroll')
tapTimeout = setTimeout(function() {

// trigger universal 'tap' with the option to cancelTouch()
// (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
var event = $.Event('tap')
event.cancelTouch = cancelAll
touch.el.trigger(event)

// trigger double tap immediately
if (touch.isDoubleTap) {
if (touch.el) touch.el.trigger('doubleTap')
touch = {}
}

// trigger single tap after 250ms of inactivity
else {
touchTimeout = setTimeout(function(){
touchTimeout = null
if (touch.el) touch.el.trigger('singleTap')
touch = {}
}, 250)
}
}, 0)
} else {
touch = {}
}
deltaX = deltaY = 0

})
// when the browser window loses focus,
// for example when a modal dialog is shown,
// cancel all ongoing events
.on('touchcancel MSPointerCancel pointercancel', cancelAll)

// scrolling the window indicates intention of the user
// to scroll, not tap or swipe, so cancel all ongoing events
$(window).on('scroll', cancelAll)
})

;['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown',
'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(eventName){
$.fn[eventName] = function(callback){ return this.on(eventName, callback) }
})
})(Zepto)