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
我必须为旋转木马编写一个简单的脚本,以检测向左或向右的滑动。
我使用指针事件代替触摸事件。
我希望这对个人有用,我欢迎任何改进我的代码的见解;我觉得很不好意思加入这个线程与显著优秀的JS开发人员。
function getSwipeX({elementId}) {
this.e = document.getElementsByClassName(elementId)[0];
this.initialPosition = 0;
this.lastPosition = 0;
this.threshold = 200;
this.diffInPosition = null;
this.diffVsThreshold = null;
this.gestureState = 0;
this.getTouchStart = (event) => {
event.preventDefault();
if (window.PointerEvent) {
this.e.setPointerCapture(event.pointerId);
}
return this.initalTouchPos = this.getGesturePoint(event);
}
this.getTouchMove = (event) => {
event.preventDefault();
return this.lastPosition = this.getGesturePoint(event);
}
this.getTouchEnd = (event) => {
event.preventDefault();
if (window.PointerEvent) {
this.e.releasePointerCapture(event.pointerId);
}
this.doSomething();
this.initialPosition = 0;
}
this.getGesturePoint = (event) => {
this.point = event.pageX
return this.point;
}
this.whatGestureDirection = (event) => {
this.diffInPosition = this.initalTouchPos - this.lastPosition;
this.diffVsThreshold = Math.abs(this.diffInPosition) > this.threshold;
(Math.sign(this.diffInPosition) > 0) ? this.gestureState = 'L' : (Math.sign(this.diffInPosition) < 0) ? this.gestureState = 'R' : this.gestureState = 'N';
return [this.diffInPosition, this.diffVsThreshold, this.gestureState];
}
this.doSomething = (event) => {
let [gestureDelta,gestureThreshold,gestureDirection] = this.whatGestureDirection();
// USE THIS TO DEBUG
console.log(gestureDelta,gestureThreshold,gestureDirection);
if (gestureThreshold) {
(gestureDirection == 'L') ? // LEFT ACTION : // RIGHT ACTION
}
}
if (window.PointerEvent) {
this.e.addEventListener('pointerdown', this.getTouchStart, true);
this.e.addEventListener('pointermove', this.getTouchMove, true);
this.e.addEventListener('pointerup', this.getTouchEnd, true);
this.e.addEventListener('pointercancel', this.getTouchEnd, true);
}
}
可以使用new调用该函数。
window.addEventListener('load', () => {
let test = new getSwipeX({
elementId: 'your_div_here'
});
})
其他回答
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] }
我之前使用的方法是,您必须检测mousedown事件,记录其x,y位置(任何相关的位置),然后检测mouseup事件,并减去两个值。
简单的水平滑动JS示例:
let touchstartX = 0
let touchendX = 0
function checkDirection() {
if (touchendX < touchstartX) alert('swiped left!')
if (touchendX > touchstartX) alert('swiped right!')
}
document.addEventListener('touchstart', e => {
touchstartX = e.changedTouches[0].screenX
})
document.addEventListener('touchend', e => {
touchendX = e.changedTouches[0].screenX
checkDirection()
})
垂直滑动也可以使用相同的逻辑。
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/
简单的JS代码示例:
document.addEventListener('touchstart', handleTouchStart, false);
document.addEventListener('touchmove', handleTouchMove, false);
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 handleTouchMove(evt) {
if ( ! xDown || ! yDown ) {
return;
}
var xUp = evt.touches[0].clientX;
var yUp = evt.touches[0].clientY;
var xDiff = xDown - xUp;
var yDiff = yDown - yUp;
if ( Math.abs( xDiff ) > Math.abs( yDiff ) ) {/*most significant*/
if ( xDiff > 0 ) {
/* right swipe */
} else {
/* left swipe */
}
} else {
if ( yDiff > 0 ) {
/* down swipe */
} else {
/* up swipe */
}
}
/* reset values */
xDown = null;
yDown = null;
};
Android测试。