How to detect Pull to refresh
Question
There are many "pull to refresh" plugins. I have already tested 5 of them. But none of them running fast (especially on old smartphones).
What is the best (buttery UX performance and responsiveness) way to check for pull to refresh?
PS: I don't need any animation. I just want to recognize if a user "pull to refresh"
5 answers
solution1
30 ACCPTED 2017-09-15 22:14:17
Performance requires minimal code
Plugins and libraries have to be written to be as flexible and general as possible, in order to solve many related problems. This means they'll always be bulkier than you need, impacting performance. It also means you'll never have to maintain that code. That's the trade off.
If performance is your goal, build it yourself.
Since ALL you need is a pull-down detection, build a simple swipe detector. Of course, you'll have to adapt this to your needs, and the event-properties, event-triggers of the OS and browser you're targeting.
Simplified from my old js-minimal-swipe-detect
var pStart = {x: 0, y:0};
var pStop = {x:0, y:0};
function swipeStart(e) {
if (typeof e['targetTouches'] !== "undefined"){
var touch = e.targetTouches[0];
pStart.x = touch.screenX;
pStart.y = touch.screenY;
} else {
pStart.x = e.screenX;
pStart.y = e.screenY;
}
}
function swipeEnd(e){
if (typeof e['changedTouches'] !== "undefined"){
var touch = e.changedTouches[0];
pStop.x = touch.screenX;
pStop.y = touch.screenY;
} else {
pStop.x = e.screenX;
pStop.y = e.screenY;
}
swipeCheck();
}
function swipeCheck(){
var changeY = pStart.y - pStop.y;
var changeX = pStart.x - pStop.x;
if (isPullDown(changeY, changeX) ) {
alert('Swipe Down!');
}
}
function isPullDown(dY, dX) {
// methods of checking slope, length, direction of line created by swipe action
return dY < 0 && (
(Math.abs(dX) <= 100 && Math.abs(dY) >= 300)
|| (Math.abs(dX)/Math.abs(dY) <= 0.3 && dY >= 60)
);
}
document.addEventListener('touchstart', function(e){ swipeStart(e); }, false);
document.addEventListener('touchend', function(e){ swipeEnd(e); }, false);
solution2
1 2017-09-19 13:38:55
have you tired these solutions?? You need to check this fiddle
var mouseY = 0;
var startMouseY = 0;
$('body').on('mousedown', function (ev) {
mouseY = ev.pageY;
startMouseY = mouseY;
$(document).mousemove(function (e) {
if (e.pageY > mouseY) {
var d = e.pageY - startMouseY;
console.log("d: " + d);
if (d >= 200)
location.reload();
$('body').css('margin-top', d/4 + 'px');
}
else
$(document).unbind("mousemove");
});
});
$('body').on('mouseup', function () {
$('body').css('margin-top', '0px');
$(document).unbind("mousemove");
});
$('body').on('mouseleave', function () {
$('body').css('margin-top', '0px');
$(document).unbind("mousemove");
});
and if you are looking for some plugin this plugin might help you
solution3
1 2019-06-07 22:43:01
What about this?
var lastScrollPosition = 0;
window.onscroll = function(event)
{
if((document.body.scrollTop >= 0) && (lastScrollPosition < 0))
{
alert("refresh");
}
lastScrollPosition = document.body.scrollTop;
}
If your browser doesn't scroll negative, then you could replace line 4 with something like this: if((document.body.scrollTop == 0) && (lastScrollPosition > 0))
Alternatively for android devices, you could swap out lastScrollPosition for "ontouchmove" or other gesture events.
solution4
0 2020-10-21 00:47:47
i know this answer has been answed by a lot many peopl but it may help someone. its based on Mr. Pryamid's answer. but his answer does not work touch screen. that only works with mouse.
this answer works well on touch screen and desktop. i have tested in chrome in desktop and chrome in android
<!DOCTYPE html>
<html>
<head>
<style>
*{
margin : 0;
padding: 0;
}
html, body {
width : 100%;
height: 100%;
}
.pull-to-refresh-container {
width : 100%;
height : 100%;
background-color: yellow;
position : relative;
}
.pull-to-refresh-content-container {
position : absolute;
top : 0;
left : 0;
width : 100%;
height : 100%;
background-color: white;
margin : 0px;
text-align : center;
}
</style>
</head>
<body>
<div class="pull-to-refresh-container">
<div class="pull-to-refresh-loader-container">
loading ...
</div>
<div class="pull-to-refresh-content-container">
here lies the content
</div>
</div>
<script>
var mouseY = 0;
var startMouseY = 0;
var container = document.querySelector(".pull-to-refresh-content-container");
container.onmousedown = (ev) => {
mouseY = ev.pageY;
startMouseY = mouseY;
container.onmousemove = (e) => {
if (e.pageY > mouseY) {
var d = e.pageY - startMouseY;
console.log("d: " + d);
container.style.marginTop = d/4 + 'px';
if (d >= 300) {
// alert("load more content");
}
} else {
container.onmousemove = null;
}
}
};
container.onmouseup = (ev) => {
container.style.marginTop = '0px';
container.onmousemove = null;
};
container.onmouseleave = (ev) => {
container.style.marginTop = '0px';
container.onmousemove = null;
};
container.ontouchstart = (ev) => {
mouseY = ev.touches[0].pageY;
startMouseY = mouseY;
container.ontouchmove = (e) => {
if (e.touches[0].pageY > mouseY) {
var d = e.touches[0].pageY - startMouseY;
console.log("d: " + d);
container.style.marginTop = d/4 + 'px';
if (d >= 300) {
// alert("load more content");
}
} else {
container.onmousemove = null;
}
}
};
container.ontouchcancel = (ev) => {
container.style.marginTop = '0px';
container.onmousemove = null;
};
container.ontouchend = (ev) => {
container.style.marginTop = '0px';
container.onmousemove = null;
};
</script>
</body>
</html>
solution5
-5 2018-05-29 14:02:18
One simple way:
$(document.body).pullToRefresh(function() { setTimeout(function() { $(document.body).pullToRefreshDone(); }, 2000); });
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