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'
  });
})

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。