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。
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
你可以监听touchstart和touchend事件,并根据事件数据计算方向和力(Codepen):
让start = null; 文档。addEventListener('touchstart', e => { const touch = e. changedtouchs[0]; Start = [touch.]clientX touch.clientY); }); 文档。addEventListener('touchend', e => { const touch = e. changedtouchs[0]; Const end = [touch.]clientX touch.clientY); document.body.innerText = " ${结束[0]-[0]开始},${结束[1]-[1]开始}'; }); 点击这里
或者你可以围绕同样的概念构建一个更符合人体工程学的API (Codepen):
const removeListener = addSwipeRightListener(document, (force, e) => {
console.info('Swiped right with force: ' + force);
});
// removeListener()
// swipe.js const { addSwipeLeftListener, addSwipeRightListener, addSwipeUpListener, addSwipeDownListener, } = (function() { // <element, {listeners: [...], handleTouchstart, handleTouchend}> const elements = new WeakMap(); function readTouch(e) { const touch = e.changedTouches[0]; if (touch == undefined) { return null; } return [touch.clientX, touch.clientY]; } function addListener(element, cb) { let elementValues = elements.get(element); if (elementValues === undefined) { const listeners = new Set(); const handleTouchstart = e => { elementValues.start = readTouch(e); }; const handleTouchend = e => { const start = elementValues.start; if (start === null) { return; } const end = readTouch(e); for (const listener of listeners) { listener([end[0] - start[0], end[1] - start[1]], e); } }; element.addEventListener('touchstart', handleTouchstart); element.addEventListener('touchend', handleTouchend); elementValues = { start: null, listeners, handleTouchstart, handleTouchend, }; elements.set(element, elementValues); } elementValues.listeners.add(cb); return () => deleteListener(element, cb); } function deleteListener(element, cb) { const elementValues = elements.get(element); const listeners = elementValues.listeners; listeners.delete(cb); if (listeners.size === 0) { elements.delete(element); element.removeEventListener('touchstart', elementValues.handleTouchstart); element.removeEventListener('touchend', elementValues.handleTouchend); } } function addSwipeLeftListener(element, cb) { return addListener(element, (force, e) => { const [x, y] = force; if (x < 0 && -x > Math.abs(y)) { cb(x, e); } }); } function addSwipeRightListener(element, cb) { return addListener(element, (force, e) => { const [x, y] = force; if (x > 0 && x > Math.abs(y)) { cb(x, e); } }); } function addSwipeUpListener(element, cb) { return addListener(element, (force, e) => { const [x, y] = force; if (y < 0 && -y > Math.abs(x)) { cb(x, e); } }); } function addSwipeDownListener(element, cb) { return addListener(element, (force, e) => { const [x, y] = force; if (y > 0 && y > Math.abs(x)) { cb(x, e); } }); } return { addSwipeLeftListener, addSwipeRightListener, addSwipeUpListener, addSwipeDownListener, } })(); // app.js function print(direction, force) { document.querySelector('#direction').innerText = direction; document.querySelector('#data').innerText = force; } addSwipeLeftListener(document, (force, e) => { print('left', force); }); addSwipeRightListener(document, (force, e) => { print('right', force); }); addSwipeUpListener(document, (force, e) => { print('up', force); }); addSwipeDownListener(document, (force, e) => { print('down', force); }); <h1>Swipe <span id="direction"></span></h1> Force (px): <span id="data"></span>
其他回答
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。
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);
};
我重做了@ruben-martinez的答案,使用来自@givanse的惊人的解决方案,使用自定义反应钩子处理滑动事件。
import React, { useEffect, useRef, useState } from "react";
export default function useSwiper() {
const [domRef, setDomRef] = useState<any>();
const xDown: React.MutableRefObject<number | null> = useRef(null);
const yDown: React.MutableRefObject<number | null> = useRef(null);
useEffect(() => {
if (!domRef) return;
function getTouches(event: React.TouchEvent<HTMLDivElement>) {
return event.touches;
}
function handleTouchStart(event: any) {
const firstTouch = getTouches(event)[0];
xDown.current = firstTouch.clientX;
yDown.current = firstTouch.clientY;
}
function handleTouchMove(event: React.TouchEvent<HTMLDivElement>) {
if (!xDown.current || !yDown.current) return;
const firstTouch = getTouches(event)[0];
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)) {
// handle horizontal swipes
if (xDiff > 0) {
// we swiped right
console.log("right");
} else {
// we swiped left
console.log("left");
}
} else {
// handle vertical swipes
if (yDiff > 0) {
// we swiped down
console.log("down");
} else {
// we swiped up
console.log("up");
}
}
}
function handleTouchEnd(event: React.TouchEvent<HTMLDivElement>) {
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, false);
domRef.removeEventListener("touchmove", handleTouchMove, false);
domRef.removeEventListener("touchend", handleTouchEnd, false);
};
}, [domRef]);
return (ref: any) => setDomRef(ref);
}
我在实现他的答案时遇到的主要挑战是不知道如何将swipe元素的ref绑定到自定义钩子中的ref。
基本上,所发生的是我们从自定义钩子返回一个函数。这个函数允许我们传入一个来自我们想要监听的滑动动作的元素的ref。自定义钩子接收到ref后,用元素的ref更新钩子状态,从而触发重新渲染,这样我们就有了实际的元素!
这种函数式的ref样式还允许我们对多个元素使用钩子。如下所示,我想使用它的项目列表,以启用滑动删除:)
import useSwiper from "./hooks/useSwipe";
const EntryCard = ({ entry, godMode, reload }: EntryProps) => {
const swiperRef = useSwiper();
const handleEntryClick =
(entry: Entry) => async (event: React.MouseEvent<HTMLDivElement>) => {
if (!godMode) return;
try {
reload((state) => !state);
} catch (err) {
console.log("Error deleting entry: ", err);
}
};
return (
<div className="item" onClick={handleEntryClick(entry)} ref={swiperRef}>
<div className="username">{entry.userName}</div>
<div className="score">{entry.weekScore}</div>
</div>
);
};
PS:你可以把函数传递给钩子来接收滑动值。谢谢:)如果你喜欢,请投票:)
threshold, timeout swipe, swipeBlockElems添加。
document.addEventListener('touchstart', handleTouchStart, false);
document.addEventListener('touchmove', handleTouchMove, false);
document.addEventListener('touchend', handleTouchEnd, false);
const SWIPE_BLOCK_ELEMS = [
'swipBlock',
'handle',
'drag-ruble'
]
let xDown = null;
let yDown = null;
let xDiff = null;
let yDiff = null;
let timeDown = null;
const TIME_THRESHOLD = 200;
const DIFF_THRESHOLD = 130;
function handleTouchEnd() {
let timeDiff = Date.now() - timeDown;
if (Math.abs(xDiff) > Math.abs(yDiff)) { /*most significant*/
if (Math.abs(xDiff) > DIFF_THRESHOLD && timeDiff < TIME_THRESHOLD) {
if (xDiff > 0) {
// console.log(xDiff, TIME_THRESHOLD, DIFF_THRESHOLD)
SWIPE_LEFT(LEFT) /* left swipe */
} else {
// console.log(xDiff)
SWIPE_RIGHT(RIGHT) /* right swipe */
}
} else {
console.log('swipeX trashhold')
}
} else {
if (Math.abs(yDiff) > DIFF_THRESHOLD && timeDiff < TIME_THRESHOLD) {
if (yDiff > 0) {
/* up swipe */
} else {
/* down swipe */
}
} else {
console.log('swipeY trashhold')
}
}
/* reset values */
xDown = null;
yDown = null;
timeDown = null;
}
function containsClassName (evntarget , classArr) {
for (var i = classArr.length - 1; i >= 0; i--) {
if( evntarget.classList.contains(classArr[i]) ) {
return true;
}
}
}
function handleTouchStart(evt) {
let touchStartTarget = evt.target;
if( containsClassName(touchStartTarget, SWIPE_BLOCK_ELEMS) ) {
return;
}
timeDown = Date.now()
xDown = evt.touches[0].clientX;
yDown = evt.touches[0].clientY;
xDiff = 0;
yDiff = 0;
}
function handleTouchMove(evt) {
if (!xDown || !yDown) {
return;
}
var xUp = evt.touches[0].clientX;
var yUp = evt.touches[0].clientY;
xDiff = xDown - xUp;
yDiff = yDown - yUp;
}