如何在iOS Web应用程序中禁用橡皮筋? [英] How to disable rubber band in iOS web apps?
问题描述
此:
$('body').on('touchmove', function(e) { e.preventDefault(); });
有效，但是将禁用整个页面的滚动，这远非理想.
此:
$('*').on('touchstart', function(e){
var element = $(this).get(0);
if ( element.scrollTop <= 0 ) element.scrollTop = 1;
if ( element.scrollTop + element.offsetHeight >= element.scrollHeight ) element.scrollTop = element.scrollHeight - element.offsetHeight - 1;
});
在具有滚动区域的页面上工作.但是，当没有滚动内容时，它将再次显示橡皮筋.
所以我的问题:
如何禁用橡皮筋效果并仍然保持-webkit-overflow-scrolling区域可滚动?
[更新]
最佳解决方案
禁止在所有不可滚动的元素(例如标签栏或导航栏)上滚动.
anElement.addEventListener('touchmove', function( event ){ event.preventDefault() };
将滚动处理程序附加到可滚动元素(例如主要内容)上.
anElement.addEventListener('touchstart', function( event ){
if( this.scrollTop === 0 ) {
this.scrollTop += 1;
} else if( this.scrollTop + this.offsetHeight >= this.scrollHeight ) {
this.scrollTop -= 1;
}
}
最近在SPA上遇到了同样的问题，其中<body>橡皮筋削弱了经验，但是我需要滚动子区域.非常感谢dSquared的建议，因为方法1最适合我.这是我对他的建议的一个小扩展，我在一个工作项目中实现了该工作，该工作一直在树上查找，以查找上面具有.scroll类的任何元素(不仅是div):
// Prevent rubber-banding of the body, but allow for scrolling elements
$('body').on('touchmove', function (e) {
var searchTerms = '.scroll, .scroll-y, .scroll-x',
$target = $(e.target),
parents = $target.parents(searchTerms);
if (parents.length || $target.hasClass(searchTerms)) {
// ignore as we want the scroll to happen
// (This is where we may need to check if at limit)
} else {
e.preventDefault();
}
});
这是CSS的样子:
body {
height: 100%;
overflow: hidden;
}
.scroll, .scroll-y, .scroll-x {
-webkit-overflow-scrolling: touch;
}
.scroll > *, .scroll-y > *, .scroll-x > * {
-webkit-transform : translateZ(0);
}
.scroll { overflow: auto; }
.scroll-y { overflow-y: auto; }
.scroll-x { overflow-x: auto; }
您只需要一个库(jQuery或 Zepto )，您就可以自然地滚动并保持强劲势头身体.此外，我还添加了translateZ来解决滚动时元素消失时遇到的一些问题，它可用于 解决方案
Ran into the same issue recently with a SPA where the <body> rubber-banding was detracting from the experience, but I needed scrolling in sub-areas. Many thanks to dSquared's suggestions, as Method 1 worked best for me. Here is my small expansion of his suggestion that I implemented in a project for work that looks all the way up the tree to find any elements (not just divs) that have a .scroll class on it:
// Prevent rubber-banding of the body, but allow for scrolling elements
$('body').on('touchmove', function (e) {
var searchTerms = '.scroll, .scroll-y, .scroll-x',
$target = $(e.target),
parents = $target.parents(searchTerms);
if (parents.length || $target.hasClass(searchTerms)) {
// ignore as we want the scroll to happen
// (This is where we may need to check if at limit)
} else {
e.preventDefault();
}
});
And here is what the CSS looks like:
body {
height: 100%;
overflow: hidden;
}
.scroll, .scroll-y, .scroll-x {
-webkit-overflow-scrolling: touch;
}
.scroll > *, .scroll-y > *, .scroll-x > * {
-webkit-transform : translateZ(0);
}
.scroll { overflow: auto; }
.scroll-y { overflow-y: auto; }
.scroll-x { overflow-x: auto; }
You only need one library (jQuery or Zepto) and you get native scrolling with momentum and no rubber-banding on the body. Also, I've added the translateZ to fix some issues I've had with elements disappearing during scrolling and it can be used to GPU accelerate your elements.
BUT (and this is a big but), as dSquared points out, the whole page rubber-bands when the scroll element is at its limit and attempted to scroll further. Personally, I consider this a failure so I'm continuing to work on it, just wanted to pitch in on trying to figure this out. Adding a check along the lines of the OP's code might be the answer, but I haven't tried it.
UPDATE (10/7/12):
After lots of work, I've gotten the following code working perfectly in iOS6 (haven't tested in anything else). No rubber-banding on the body, no more issues when at the limit of the scroll area, and it has native scrolling performance throughout. It's obviously a lot more code that originally, but I think this will give the behavior closest to the OP's goals.
(function registerScrolling($) {
var prevTouchPosition = {},
scrollYClass = 'scroll-y',
scrollXClass = 'scroll-x',
searchTerms = '.' + scrollYClass + ', .' + scrollXClass;
$('body').on('touchstart', function (e) {
var $scroll = $(e.target).closest(searchTerms),
targetTouch = e.originalEvent.targetTouches[0];
// Store previous touch position if within a scroll element
prevTouchPosition = $scroll.length ? { x: targetTouch.pageX, y: targetTouch.pageY } : {};
});
$('body').on('touchmove', function (e) {
var $scroll = $(e.target).closest(searchTerms),
targetTouch = e.originalEvent.targetTouches[0];
if (prevTouchPosition && $scroll.length) {
// Set move helper and update previous touch position
var move = {
x: targetTouch.pageX - prevTouchPosition.x,
y: targetTouch.pageY - prevTouchPosition.y
};
prevTouchPosition = { x: targetTouch.pageX, y: targetTouch.pageY };
// Check for scroll-y or scroll-x classes
if ($scroll.hasClass(scrollYClass)) {
var scrollHeight = $scroll[0].scrollHeight,
outerHeight = $scroll.outerHeight(),
atUpperLimit = ($scroll.scrollTop() === 0),
atLowerLimit = (scrollHeight - $scroll.scrollTop() === outerHeight);
if (scrollHeight > outerHeight) {
// If at either limit move 1px away to allow normal scroll behavior on future moves,
// but stop propagation on this move to remove limit behavior bubbling up to body
if (move.y > 0 && atUpperLimit) {
$scroll.scrollTop(1);
e.stopPropagation();
} else if (move.y < 0 && atLowerLimit) {
$scroll.scrollTop($scroll.scrollTop() - 1);
e.stopPropagation();
}
// If only moving right or left, prevent bad scroll.
if(Math.abs(move.x) > 0 && Math.abs(move.y) < 3){
e.preventDefault()
}
// Normal scrolling behavior passes through
} else {
// No scrolling / adjustment when there is nothing to scroll
e.preventDefault();
}
} else if ($scroll.hasClass(scrollXClass)) {
var scrollWidth = $scroll[0].scrollWidth,
outerWidth = $scroll.outerWidth(),
atLeftLimit = $scroll.scrollLeft() === 0,
atRightLimit = scrollWidth - $scroll.scrollLeft() === outerWidth;
if (scrollWidth > outerWidth) {
if (move.x > 0 && atLeftLimit) {
$scroll.scrollLeft(1);
e.stopPropagation();
} else if (move.x < 0 && atRightLimit) {
$scroll.scrollLeft($scroll.scrollLeft() - 1);
e.stopPropagation();
}
// If only moving up or down, prevent bad scroll.
if(Math.abs(move.y) > 0 && Math.abs(move.x) < 3){
e.preventDefault();
}
// Normal scrolling behavior passes through
} else {
// No scrolling / adjustment when there is nothing to scroll
e.preventDefault();
}
}
} else {
// Prevent scrolling on non-scrolling elements
e.preventDefault();
}
});
})(jQuery);
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