我正在创建一个使用HTML5拖放API的网站。
但是,为了增加用户体验,我希望在用户拖动不可拖动的元素时防止出现幻影。这甚至可能吗?
此外,默认情况下几乎每个元素似乎都是“可拖动的”。可以单击然后迅速将几乎任何元素拖到浏览器中,这会与no-drop
光标一起创建幻影图像。有什么方法可以防止这种行为?
draggable="false"
不起作用。user-select: none
不起作用。pointer-events: none
不起作用。event.preventDefault()
上的[mousedown
无效。event.preventDefault()
上的[dragstart
也不起作用。我没有主意,到目前为止,在网上找到有关此信息的事实非常困难。我发现以下thread,但是,再次出现draggable="false"
在我的情况下似乎不起作用。
下面是一个屏幕快照,显示它不起作用;当然,您在屏幕截图中看不到我的光标,但是尽管如此,您仍可以看到我如何将数字向左拖动。
[我相信此问题可能与其具有dragover
和drop
事件的父项有关。尽管如此,我还是很傻。
...
<body>
...
<div id="backgammon-board-container">
<div class="column" id="left-column">
<div class="quadrant" id="third-quadrant">
<div class="point odd top-point" id="point-13-12"><text>13</text>
<div class="checker player-one-checker" id="checker-03" draggable="true"></div>
</div>
</div>
</div>
...
</div>
</body>
</html>
#backgammon-board-container {
height: 100vh;
width: 60vw;
position: absolute;
right: 0;
display: flex;
}
.column {
height: 100%;
display: flex;
flex-direction: column; /* column-reverse for player two perspective */
}
#left-column {
flex: 6;
}
.quadrant {
flex: 1;
display: flex;
}
.point {
flex: 1;
padding: 10px 0;
display: flex;
flex-direction: column;
align-items: center;
}
.checker {
z-index: 1;
width: 48px;
height: 48px;
border-radius: 50%;
}
text {
position: fixed;
font-family: impact;
font-size: 24px;
color: white;
display: flex;
justify-content: center;
align-items: center;
user-select: none;
pointer-events: none;
}
const p1checkers = document.getElementsByClassName('player-one-checker');
const p2checkers = document.getElementsByClassName('player-two-checker');
const pointClass = document.getElementsByClassName('point');
function setTurn(player) {
if (player === 'p1') {
allowCheckerMovement = p1checkers;
disallowCheckerMovement = p2checkers;
} else {
allowCheckerMovement = p2checkers;
disallowCheckerMovement = p1checkers;
}
// enable checker control for player
for (var i = 0; i < allowCheckerMovement.length; i++) {
allowCheckerMovement[i].style.cursor = 'pointer';
allowCheckerMovement[i].setAttribute('draggable', true);
allowCheckerMovement[i].addEventListener('dragstart', start); // for drag-and-drop.js
allowCheckerMovement[i].addEventListener('dragend', stop); // for drag-and-drop.js
}
// disable checker control for player
for (var i = 0; i < disallowCheckerMovement.length; i++) {
disallowCheckerMovement[i].style.cursor = 'default';
disallowCheckerMovement[i].setAttribute('draggable', false);
disallowCheckerMovement[i].removeEventListener('dragstart', start); // for drag-and-drop.js
disallowCheckerMovement[i].removeEventListener('dragend', stop); // for drag-and-drop.js
}
// allow drag and drop
for (var i = 0; i < pointClass.length; i++) {
pointClass[i].addEventListener('dragover', allowDrop); // for drag-and-drop.js
pointClass[i].addEventListener('drop', droppedOn); // for drag-and-drop.js
}
}
function start(event) {
var checker = event.target;
event.dataTransfer.setData('text/plain', checker.id);
event.dataTransfer.effectAllowed = 'move';
window.requestAnimationFrame(function(){
checker.style.visibility = 'hidden';
});
}
function allowDrop(event) {
event.preventDefault();
}
function droppedOn(event) {
event.preventDefault();
var data = event.dataTransfer.getData('text/plain');
event.target.appendChild(document.getElementById(data));
}
function stop(event){
var element = event.srcElement;
window.requestAnimationFrame(function(){
element.style.visibility = 'visible';
});
}
这是您要寻找的解决方案。 ;)
对于任何需要拖动的内容,只需添加'enable-drag'CSS类。
$('*:not(".enable-drag")').on('dragstart', function (e) {
e.preventDefault();
return false;
});