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  • js 移动端判断滑动方向

    <!DOCTYPE html>
    <html lang="en">
    
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    </head>
    
    <body>
    
    </body>
    
    <script>
        var startx, starty;
        //获得角度
        function getAngle(angx, angy) {
            return Math.atan2(angy, angx) * 180 / Math.PI;
        };
    
        //根据起点终点返回方向 1向上 2向下 3向左 4向右 0未滑动
        function getDirection(startx, starty, endx, endy) {
            var angx = endx - startx;
            var angy = endy - starty;
            var result = 0;
    
            //如果滑动距离太短
            if (Math.abs(angx) < 2 && Math.abs(angy) < 2) {
                return result;
            }
    
            var angle = getAngle(angx, angy);
            if (angle >= -135 && angle <= -45) {
                result = 1;
            } else if (angle > 45 && angle < 135) {
                result = 2;
            } else if ((angle >= 135 && angle <= 180) || (angle >= -180 && angle < -135)) {
                result = 3;
            } else if (angle >= -45 && angle <= 45) {
                result = 4;
            }
    
            return result;
        }
    
    
        //手指接触屏幕
        document.addEventListener("touchstart", function(e) {
            console.log(e)
            startx = e.touches[0].pageX;
            starty = e.touches[0].pageY;
    
        }, false);
    
        //手指离开屏幕
        document.addEventListener("touchend", function(e) {
            console.log(e)
    
            var endx, endy;
            endx = e.changedTouches[0].pageX;
            endy = e.changedTouches[0].pageY;
    
            var direction = getDirection(startx, starty, endx, endy);
            switch (direction) {
                case 0:
                    alert('未滑动')
                    break;
                case 1:
                    alert('向上')
                    break;
                case 2:
                    alert('向下')
                    break;
                case 3:
                    alert('向左')
                    break;
                case 4:
                    alert('向右')
                    break;
                default:
            }
        }, false);
    </script>
    
    </html>
    
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  • 原文地址:https://www.cnblogs.com/shemingxin/p/13519760.html
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