javascript - 通过iPhone和Android上的JavaScript检测手指滑动(Detect a finger swipe through JavaScript on the iPhone and Android)

Question

How can you detect that a user swiped his finger in some direction over a web page with JavaScript?(您如何使用JavaScript在网页上检测到用户向某个方向滑动手指？)

I was wondering if there was one solution that would work for websites on both the iPhone and an Android phone.(我想知道是否存在一种适用于iPhone和Android手机上的网站的解决方案。)

  ask by 827 translate from so

Answer 1

Simple vanilla JS code sample:(简单的原始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 ) {
            /* left swipe */ 
        } else {
            /* right swipe */
        }                       
    } else {
        if ( yDiff > 0 ) {
            /* up swipe */ 
        } else { 
            /* down swipe */
        }                                                                 
    }
    /* reset values */
    xDown = null;
    yDown = null;                                             
};

Tested in Android.(在Android上测试。)