如何检测用户用JavaScript在网页上向某个方向滑动手指?
我想知道是否有一种解决方案可以同时适用于iPhone和Android手机上的网站。
如何检测用户用JavaScript在网页上向某个方向滑动手指?
我想知道是否有一种解决方案可以同时适用于iPhone和Android手机上的网站。
当前回答
一个如何使用偏移量的例子。
// at least 100 px are a swipe // you can use the value relative to screen size: window.innerWidth * .1 const offset = 100; let xDown, yDown window.addEventListener('touchstart', e => { const firstTouch = getTouch(e); xDown = firstTouch.clientX; yDown = firstTouch.clientY; }); window.addEventListener('touchend', e => { if (!xDown || !yDown) { return; } const { clientX: xUp, clientY: yUp } = getTouch(e); const xDiff = xDown - xUp; const yDiff = yDown - yUp; const xDiffAbs = Math.abs(xDown - xUp); const yDiffAbs = Math.abs(yDown - yUp); // at least <offset> are a swipe if (Math.max(xDiffAbs, yDiffAbs) < offset ) { return; } if (xDiffAbs > yDiffAbs) { if ( xDiff > 0 ) { console.log('left'); } else { console.log('right'); } } else { if ( yDiff > 0 ) { console.log('up'); } else { console.log('down'); } } }); function getTouch (e) { return e.changedTouches[0] }
其他回答
函数检查水平方向和垂直方向,以确定哪个滑动更长,以防止执行两个指令,因为不可能进行完美的单向滑动。滑动总是在X和Y上有偏差。
let touchstartX = 0;
let touchendX = 0;
let touchstartY = 0;
let touchendY = 0;
function checkDirection() {
let difX = touchstartX - touchendX;
let difY = touchstartY - touchendY;
if (Math.abs(difX) > Math.abs(difY)) {
if (touchendX < touchstartX) {/*left*/}
if (touchendX > touchstartX) {/*right*/}
} else {
if (touchendY < touchstartY) {/*up*/}
if (touchendY > touchstartY) {/*down*/}
}
};
document.addEventListener('touchstart', e => {
e.preventDefault();
touchstartX = e.changedTouches[0].screenX;
touchstartY = e.changedTouches[0].screenY;
});
document.addEventListener('touchend', e => {
e.preventDefault();
touchendX = e.changedTouches[0].screenX;
touchendY = e.changedTouches[0].screenY;
checkDirection();
});
使用两个:
jQuery移动控件:在大多数情况下都可以工作,特别是当你在开发使用其他jQuery插件的应用程序时,最好使用jQuery移动控件。请访问:https://www.w3schools.com/jquerymobile/jquerymobile_events_touch.asp
锤子时间!一个最好的,轻量级和快速的基于javascript的库。请访问:https://hammerjs.github.io/
jQuery Mobile还包括滑动支持:http://api.jquerymobile.com/swipe/
例子
$("#divId").on("swipe", function(event) {
alert("It's a swipe!");
});
如果你只需要滑动,你最好只使用你需要的部分。 这应该适用于任何触摸设备。
这是经过gzip压缩,缩小,babel等大约450字节。
我根据其他答案编写了下面的类,它使用移动百分比而不是像素,以及一个事件分派器模式来挂钩/取消挂钩。
像这样使用它:
const dispatcher = new SwipeEventDispatcher(myElement);
dispatcher.on('SWIPE_RIGHT', () => { console.log('I swiped right!') })
export class SwipeEventDispatcher { constructor(element, options = {}) { this.evtMap = { SWIPE_LEFT: [], SWIPE_UP: [], SWIPE_DOWN: [], SWIPE_RIGHT: [] }; this.xDown = null; this.yDown = null; this.element = element; this.options = Object.assign({ triggerPercent: 0.3 }, options); element.addEventListener('touchstart', evt => this.handleTouchStart(evt), false); element.addEventListener('touchend', evt => this.handleTouchEnd(evt), false); } on(evt, cb) { this.evtMap[evt].push(cb); } off(evt, lcb) { this.evtMap[evt] = this.evtMap[evt].filter(cb => cb !== lcb); } trigger(evt, data) { this.evtMap[evt].map(handler => handler(data)); } handleTouchStart(evt) { this.xDown = evt.touches[0].clientX; this.yDown = evt.touches[0].clientY; } handleTouchEnd(evt) { const deltaX = evt.changedTouches[0].clientX - this.xDown; const deltaY = evt.changedTouches[0].clientY - this.yDown; const distMoved = Math.abs(Math.abs(deltaX) > Math.abs(deltaY) ? deltaX : deltaY); const activePct = distMoved / this.element.offsetWidth; if (activePct > this.options.triggerPercent) { if (Math.abs(deltaX) > Math.abs(deltaY)) { deltaX < 0 ? this.trigger('SWIPE_LEFT') : this.trigger('SWIPE_RIGHT'); } else { deltaY > 0 ? this.trigger('SWIPE_UP') : this.trigger('SWIPE_DOWN'); } } } } export default SwipeEventDispatcher;
touchStart和touchEnd的句柄:
var handleSwipe = function(elem,callbackOnRight, callbackOnLeft, callbackOnDown,
callbackOnUp) => {
elem.ontouchstart = handleTouchStart;
elem.ontouchend = handleTouchEnd;
var xDown = null;
var yDown = null;
function getTouches(evt) {
return evt.touches || // browser API
evt.originalEvent.touches; // jQuery
}
function handleTouchStart(evt) {
const firstTouch = getTouches(evt)[0];
xDown = firstTouch.clientX;
yDown = firstTouch.clientY;
};
function handleTouchEnd(evt) {
if (!xDown || !yDown) {
return;
}
var xUp = evt.changedTouches[0].clientX;
var yUp = evt.changedTouches[0].clientY;
var xDiff = xDown - xUp;
var yDiff = yDown - yUp;
var minDif = 30;
console.log(`xDiff:${xDiff}, yDiff:${yDiff}`);
if (Math.abs(xDiff) > Math.abs(yDiff)) {
if (xDiff > minDif) {
if (callbackOnLeft)
callbackOnLeft();
} else if (xDiff < -1 * minDif){
if (callbackOnRight)
callbackOnRight();
}
} else {
if (yDiff > minDif) {
if (callbackOnDown)
callbackOnDown();
} else if (yDiff < -1* minDif){
if (callbackOnUp)
callbackOnUp();
}
}
xDown = null;
yDown = null;
};
}