如何在程序中中止jQuery拖动操作?
使用jQuery UI,用户开始拖动操作。当拖动时,会发生异步事件导致拖动的元素被删除(例如基于计时器的刷新)。在刷新之前,我想在避免已删除元素的错误之前完成以下操作:
element.trigger('dragstop');
但是那似乎没有起作用。
如何在程序中中止jQuery拖动操作?
使用jQuery UI,用户开始拖动操作。当拖动时,会发生异步事件导致拖动的元素被删除(例如基于计时器的刷新)。在刷新之前,我想在避免已删除元素的错误之前完成以下操作:
element.trigger('dragstop');
但是那似乎没有起作用。
false
即可。按照jQuery UI的设计,拖动过程中官方不允许取消拖动[1] -- 我不太赞同这种情况,但事实就是这样。
如果你想要在拖动过程中可靠地取消拖动,你需要结合一些技巧[2, 3]:
$( window ).keydown( function( e ){
if( e.keyCode == 27 ) {
var mouseMoveEvent = document.createEvent("MouseEvents");
var offScreen = -50000;
mouseMoveEvent.initMouseEvent(
"mousemove", //event type : click, mousedown, mouseup, mouseover, etc.
true, //canBubble
false, //cancelable
window, //event's AbstractView : should be window
1, // detail : Event's mouse click count
offScreen, // screenX
offScreen, // screenY
offScreen, // clientX
offScreen, // clientY
false, // ctrlKey
false, // altKey
false, // shiftKey
false, // metaKey
0, // button : 0 = click, 1 = middle button, 2 = right button
null // relatedTarget : Only used with some event types (e.g. mouseover and mouseout).
// In other cases, pass null.
);
// Move the mouse pointer off screen so it won't be hovering a droppable
document.dispatchEvent(mouseMoveEvent);
// This is jQuery speak for:
// for all ui-draggable elements who have an active draggable plugin, that
var dragged = $('.ui-draggable:data(draggable)')
// either are ui-draggable-dragging, or, that have a helper that is ui-draggable-dragging
.filter(function(){return $('.ui-draggable-dragging').is($(this).add(($(this).data('draggable') || {}).helper))});
// We need to restore this later
var origRevertDuration = dragged.draggable('option', 'revertDuration');
var origRevertValue = dragged.draggable('option', 'revert');
dragged
// their drag is being reverted
.draggable('option', 'revert', true)
// no revert animation
.draggable('option', 'revertDuration', 0)
// and the drag is forcefully ended
.trigger('mouseup')
// restore revert animation settings
.draggable('option', 'revertDuration', origRevertDuration)
// restore revert value
.draggable('option', 'revert', origRevertValue);
}
}
现在,这并不美观。但它能够工作。即使在悬停接受可放置对象时取消。
玩得开心。
[1] - http://bugs.jqueryui.com/ticket/8414
[2] - https://gist.github.com/3517765
[3] - https://forum.jquery.com/topic/how-to-cancel-drag-while-dragging
drag
事件。data()
方法来确定一个元素是否可拖动:$("div").draggable({
drag: function() {
return !$(this).data("disabledrag");
},
revert: true
});
然后在您的异步操作中,如果正在拖动的元素是已删除的元素(我假设您有一些将DOM元素与来自服务器的数据关联的系统),则可以设置该数据:
var $dragging = $(".ui-draggable-dragging");
if ($dragging.length) {
// If this is the item that was deleted, stop dragging:
if ($dragging.attr("id") === "item-one") {
$dragging.data("disabledrag", true);
$dragging.addClass("deleted").html("This item has been deleted!");
}
}
我已经更新了我的示例这里。第一个div
将在5秒后被“删除”。