javascript - Jquery UI Selectable - 选择多个元素

Question

我正在尝试在我的应用程序中实现一个选择多个元素的功能，但由于我是前端开发的新手，所以我在控制 JavaScript 的事件和 CSS 时遇到了一些麻烦。我找到了 this post所以我用它作为我的指南。

在使用 Selectable() 函数之前，我添加了一个类(带有一些 CSS)来为我的元素提供被选中的外观(一次单击一个)，如果我想取消选中它，我只需单击 Canvas (触发删除类“selectedEffect”的函数)。

但现在我想选择多个元素(将来我希望能够对它们进行分组)，所以我开始使用 Selectable() 并且正如我所说，我发现那篇文章对我有部分帮助。我能够将这段代码复制到我的元素中:

// this creates the selected variable
// we are going to store the selected objects in here
var selected = $([]), offset = {top:0, left:0}; 

$( "#canvas > div" ).draggable({
    start: function(ev, ui) {
        editorContent.addClass("hidden");

    if ($(this).hasClass("ui-selected")){
        selected = $(".ui-selected").each(function() {
           var el = $(this);
           el.data("offset", el.offset());
        });
    }
    else {
        selected = $([]);
        $("#canvas > div").removeClass("ui-selected");
    }
    offset = $(this).offset();
},
drag: function(ev, ui) {
    $(currentElement).removeClass("selectedEffect");
    $(currentArrow).removeClass("selectedArrow");
    var dt = ui.style.top - offset.top, dl = ui.style.left - offset.left;
    // take all the elements that are selected expect $("this"), which is    the element being dragged and loop through each.
    selected.not(this).each(function() {
         // create the variable for we don't need to keep calling $("this")
         // el = current element we are on
         // off = what position was this element at when it was selected, before drag
         var el = $(this), off = el.data("offset");
        el.css({top: off.top + dt, left: off.left + dl});
    });
}
});

$( "#canvas" ).selectable();

// manually trigger the "select" of clicked elements
$( "#canvas > div" ).click( function(e){
    if (e.metaKey == false) {
        // if command key is pressed don't deselect existing elements
        $( "#canvas > div" ).removeClass("ui-selected");
        $(this).addClass("ui-selecting");
    }
    else {
        if ($(this).hasClass("ui-selected")) {
            // remove selected class from element if already selected
            $(this).removeClass("ui-selected");
        }
        else {
            // add selecting class if not
            $(this).addClass("ui-selecting");
        }
    }

  $( "#canvas" ).data("canvas")._mouseStop(null);
});

但是，实现这个功能后，我仍然有一些错误:

1. 无法同时拖动多个选定的对象
2. 如果我单击一个元素然后单击 Canvas (以取消选择它)，“selectedEffect”不会消失。

Answer 1

我刚刚想通了。问题是，由于我要向 Canvas 动态添加元素，所以我必须在创建时将以下函数绑定(bind)到我的可拖动元素:

 $( "#myNewlyCreatedElement" ).draggable({
     start: function (event, ui) {

         if ($this.hasClass("ui-selected")) {
             // if this is selected, attach current offset
             // of each selected element to that element
             selected = $(".ui-selected").each(function() {
                 var el = $(this);
                 el.data("offset", el.offset());
             });
         } else {
             // if this is not selected, clear current selection
             selected = $([]);
             $( "#canvas > div" ).removeClass("ui-selected");
         }
         offset = $this.offset();
     },

     drag: function (event, ui) {
         // drag all selected elements simultaneously
         var dt = ui.position.top - offset.top, dl = ui.position.left - offset.left;
         selected.not(this).each(function() {
             var $this = $(this);
             var elOffset = $this.data("offset");
             $this.css({top: elOffset.top + dt, left: elOffset.left + dl});
         });
     }
 });