Question

如何限制拖动只能在一个方向上拖动？
即axis: 'y'时只有顶部或仅底部并且只在axis: 'x'

时才向左或向右

这意味着，如果我想将可拖动的(with axis set to 'y')仅拖动到bottom，那么它应该无法将其拖到顶部，即当它试图拖向它时它应该保留在其位置顶

这是我尝试过的但不起作用，即拖延仍然被拖向上升

$('. draggable').draggable({
    axis: 'y',
    handle: '.top'
    drag: function( event, ui ) {
       var distance = ui.originalPosition.top - ui.position.top;

       // if dragged towards top
       if (distance > 0) { 
           //then set it to its initial state
           $('.draggable').css({top: ui.originalPosition.top + 'px'});
       }
   }
});

Answer 1

回答我自己的问题（除上述答案之外的其他选择）以帮助他人

根据具体情况说仅允许在轴上向下拖动：'y'

<div class="draggable">draggable only downwards</div>

<强> CSS

.draggable {
    position:absolute;
    top:0px;
    background:pink;
    height:100px;
    width:100%;
    left: 0px;
    text-align:center;
}

<强>脚本

$('.draggable').draggable({
    axis: "y"
});    

$('.draggable').on('mousedown', function() {
    var x1 = x2 = $(".draggable").position().left;
    var y1 = $(".draggable").position().top;
    var y2 = ($(window).height() + $(".draggable").position().top);
    $(".draggable").draggable('option', 'containment', [x1, y1, x2, y2]);
});

<强> Demo Link

Answer 2

方法1 - 使用还原黑客

<强> jsFiddle

 $('.draggable').draggable({
     axis: "y",
     start: function (event, ui) {
         start = ui.position.top;
     },
     stop: function (event, ui) {
         stop = ui.position.top;

         if (start > stop) {
             $('.draggable').css({top: ui.originalPosition.top + 'px'});
         }
     }
 });

方法2 - 禁用拖动而不还原

<强> jsFiddle 2

基本上，方法2只是在容器中限制可拖动元素，并使用可拖动元素移动容器。看看，它简单，但有效。

$('.draggable').draggable({
    axis: "y",
    containment: "#containment-wrapper",
    scroll: true,
    scrollSensitivity: 100,
    scrollSpeed: 25,
    cursor: '-moz-grabbing'
});
$('.draggable').mousemove(function () {
    var x = $('.draggable').css('top');
    $("#containment-wrapper").css({
        top: x
    });
});

方法3 与方法2相同，仅使用拖动功能。

<强> jsFiddle 3

$('.draggableDown').draggable({
    axis: "y",
    containment: "#containment-wrapperDown",
    scroll: true,
    scrollSensitivity: 100,
    scrollSpeed: 25,
    cursor: '-moz-grabbing',
    drag: function () {
        var x = $('.draggableDown').position().top;
        $("#containment-wrapperDown").css({
            top: x
        });
    }
});

仅在一个方向上限制拖动

2 个答案: