js判断手指滑动方向（移动端）

来源：互联网发布：软件配置管理人员职责编辑：程序博客网时间：2024/04/30 08:28

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<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) {

startx = e.touches[0].pageX;

starty = e.touches[0].pageY;

}, false);

//手指离开屏幕

document.addEventListener("touchend", function(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>
</head>
<body>
</body>
</html>

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