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
一些mod的顶部回答(不能评论…)来处理短滑动
document.addEventListener('touchstart', handleTouchStart, false);
document.addEventListener('touchmove', handleTouchMove, false);
var xDown = null;
var yDown = null;
function handleTouchStart(evt) {
xDown = evt.touches[0].clientX;
yDown = evt.touches[0].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 )>150){ //to deal with to short swipes
if ( Math.abs( xDiff ) > Math.abs( yDiff ) ) {/*most significant*/
if ( xDiff > 0 ) {/* left swipe */
alert('left!');
} else {/* right swipe */
alert('right!');
}
} else {
if ( yDiff > 0 ) {/* up swipe */
alert('Up!');
} else { /* down swipe */
alert('Down!');
}
}
/* reset values */
xDown = null;
yDown = null;
}
};
其他回答
一些mod的顶部回答(不能评论…)来处理短滑动
document.addEventListener('touchstart', handleTouchStart, false);
document.addEventListener('touchmove', handleTouchMove, false);
var xDown = null;
var yDown = null;
function handleTouchStart(evt) {
xDown = evt.touches[0].clientX;
yDown = evt.touches[0].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 )>150){ //to deal with to short swipes
if ( Math.abs( xDiff ) > Math.abs( yDiff ) ) {/*most significant*/
if ( xDiff > 0 ) {/* left swipe */
alert('left!');
} else {/* right swipe */
alert('right!');
}
} else {
if ( yDiff > 0 ) {/* up swipe */
alert('Up!');
} else { /* down swipe */
alert('Down!');
}
}
/* reset values */
xDown = null;
yDown = null;
}
};
我重做了@givanse的解决方案，使其发挥React钩子的作用。输入是一些可选的事件监听器，输出是一个功能性的ref(需要是功能性的，以便当/如果ref改变时钩子可以重新运行)。
还添加了垂直/水平滑动阈值参数，这样小的运动不会意外触发事件监听器，但这些可以设置为0，以更接近地模拟原始答案。
提示:为了获得最佳性能，应该记住事件侦听器输入函数。
function useSwipeDetector({
// Event listeners.
onLeftSwipe,
onRightSwipe,
onUpSwipe,
onDownSwipe,
// Threshold to detect swipe.
verticalSwipeThreshold = 50,
horizontalSwipeThreshold = 30,
}) {
const [domRef, setDomRef] = useState(null);
const xDown = useRef(null);
const yDown = useRef(null);
useEffect(() => {
if (!domRef) {
return;
}
function handleTouchStart(evt) {
const [firstTouch] = evt.touches;
xDown.current = firstTouch.clientX;
yDown.current = firstTouch.clientY;
};
function handleTouchMove(evt) {
if (!xDown.current || !yDown.current) {
return;
}
const [firstTouch] = evt.touches;
const xUp = firstTouch.clientX;
const yUp = firstTouch.clientY;
const xDiff = xDown.current - xUp;
const yDiff = yDown.current - yUp;
if (Math.abs(xDiff) > Math.abs(yDiff)) {/*most significant*/
if (xDiff > horizontalSwipeThreshold) {
if (onRightSwipe) onRightSwipe();
} else if (xDiff < -horizontalSwipeThreshold) {
if (onLeftSwipe) onLeftSwipe();
}
} else {
if (yDiff > verticalSwipeThreshold) {
if (onUpSwipe) onUpSwipe();
} else if (yDiff < -verticalSwipeThreshold) {
if (onDownSwipe) onDownSwipe();
}
}
};
function handleTouchEnd() {
xDown.current = null;
yDown.current = null;
}
domRef.addEventListener("touchstart", handleTouchStart, false);
domRef.addEventListener("touchmove", handleTouchMove, false);
domRef.addEventListener("touchend", handleTouchEnd, false);
return () => {
domRef.removeEventListener("touchstart", handleTouchStart);
domRef.removeEventListener("touchmove", handleTouchMove);
domRef.removeEventListener("touchend", handleTouchEnd);
};
}, [domRef, onLeftSwipe, onRightSwipe, onUpSwipe, onDownSwipe, verticalSwipeThreshold, horizontalSwipeThreshold]);
return (ref) => setDomRef(ref);
};
在这里的建议之上，我将跟踪手指号码，因为如果你同时用两个手指触摸，它将获得X位置，而不会导致一个奇怪的行为，而且，你可能想要设置一个“距离”最小值，这样用户在通过你的网站或应用程序触摸时就不会错误地触发滑动。
//Swipe
let touchstartX = 0
let touchendX = 0
let fingerCount = 0
const checkDirection = () => {
const distance = 50 //Minimum distance for the swipe to work
//left
if (touchendX < touchstartX && (touchstartX - touchendX) > distance ){
//Do something cool
}
//right
if (touchendX > touchstartX && (touchendX - touchstartX) > distance){
//Do something cooler
}
document.addEventListener('touchstart', e => {
fingerCount = e.touches.length
touchstartX = e.changedTouches[0].clientX
})
document.addEventListener('touchend', e => {
touchendX = e.changedTouches[0].clientX
if(fingerCount === 1){
checkDirection()
}
})
我重新包装了TouchWipe作为一个简短的jquery插件:detectSwipe
我遇到了触摸端处理程序连续发射的问题，而用户正在拖着一个手指。我不知道这是不是因为我做错了什么但是我重新连接了这个用touchmove来累积移动touchend实际上触发了回调。
我还需要大量这样的实例，所以我添加了启用/禁用方法。
还有一个阈值，短刷不会触发。每次Touchstart 0的计数器。
您可以动态地更改target_node。创建时启用是可选选项。
/** Usage: */
touchevent = new Modules.TouchEventClass(callback, target_node);
touchevent.enable();
touchevent.disable();
/**
*
* Touch event module
*
* @param method set_target_mode
* @param method __touchstart
* @param method __touchmove
* @param method __touchend
* @param method enable
* @param method disable
* @param function callback
* @param node target_node
*/
Modules.TouchEventClass = class {
constructor(callback, target_node, enable=false) {
/** callback function */
this.callback = callback;
this.xdown = null;
this.ydown = null;
this.enabled = false;
this.target_node = null;
/** move point counts [left, right, up, down] */
this.counts = [];
this.set_target_node(target_node);
/** Enable on creation */
if (enable === true) {
this.enable();
}
}
/**
* Set or reset target node
*
* @param string/node target_node
* @param string enable (optional)
*/
set_target_node(target_node, enable=false) {
/** check if we're resetting target_node */
if (this.target_node !== null) {
/** remove old listener */
this.disable();
}
/** Support string id of node */
if (target_node.nodeName === undefined) {
target_node = document.getElementById(target_node);
}
this.target_node = target_node;
if (enable === true) {
this.enable();
}
}
/** enable listener */
enable() {
this.enabled = true;
this.target_node.addEventListener("touchstart", this.__touchstart.bind(this));
this.target_node.addEventListener("touchmove", this.__touchmove.bind(this));
this.target_node.addEventListener("touchend", this.__touchend.bind(this));
}
/** disable listener */
disable() {
this.enabled = false;
this.target_node.removeEventListener("touchstart", this.__touchstart);
this.target_node.removeEventListener("touchmove", this.__touchmove);
this.target_node.removeEventListener("touchend", this.__touchend);
}
/** Touchstart */
__touchstart(event) {
event.stopPropagation();
this.xdown = event.touches[0].clientX;
this.ydown = event.touches[0].clientY;
/** reset count of moves in each direction, [left, right, up, down] */
this.counts = [0, 0, 0, 0];
}
/** Touchend */
__touchend(event) {
let max_moves = Math.max(...this.counts);
if (max_moves > 500) { // set this threshold appropriately
/** swipe happened */
let index = this.counts.indexOf(max_moves);
if (index == 0) {
this.callback("left");
} else if (index == 1) {
this.callback("right");
} else if (index == 2) {
this.callback("up");
} else {
this.callback("down");
}
}
}
/** Touchmove */
__touchmove(event) {
event.stopPropagation();
if (! this.xdown || ! this.ydown) {
return;
}
let xup = event.touches[0].clientX;
let yup = event.touches[0].clientY;
let xdiff = this.xdown - xup;
let ydiff = this.ydown - yup;
/** Check x or y has greater distance */
if (Math.abs(xdiff) > Math.abs(ydiff)) {
if (xdiff > 0) {
this.counts[0] += Math.abs(xdiff);
} else {
this.counts[1] += Math.abs(xdiff);
}
} else {
if (ydiff > 0) {
this.counts[2] += Math.abs(ydiff);
} else {
this.counts[3] += Math.abs(ydiff);
}
}
}
}
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