学习YUI.Ext第五日--做拖放Darg&Drop

站长资源 2024/11/26 佚名

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拖放某个元素Darg&Drop是windows（视窗）问世时的一个重要特征。现在我们要在浏览器里面实现，怎么做呢？先看看基本例子：

复制代码代码如下:
YAHOO.example.DDApp = function() {
    var dd;
    return {
        init2: function() {

//   var dropzone =["dz"];
//   for(i in dropzone){
//           new YAHOO.util.DDTarget(dropzone[i]);
//    };
   var  draggable =["dd_1","dd_2","dd_3"]; //数组存放DargDrop的ID
    Draggable = function(id, sGroup) {
    //建立DragDrop对象。这个必须由YAHOO.util.DragDrop的子类来调用
    //Sets up the DragDrop object. Must be called in the constructor of any YAHOO.util.DragDrop subclass
    this.init(id, sGroup);
      }
   Draggable.prototype = new YAHOO.util.DD(); //继承父类
   Draggable.prototype.startDrag = function(x, y) {
          YAHOO.util.Dom.setStyle(this.getEl(), "opacity", 0.5);
      }
   Draggable.prototype.endDrag = function(e) { //拖放后返回原点
    var draggable = this.getEl();
    YAHOO.util.Dom.setStyle(draggable, "opacity", 1.0);
    draggable.style.left = "0px";
    draggable.style.top  = "0px";
   }
   for(i in draggable){
     new Draggable(draggable[i]);
   }

        }
    }
} ();
注意的地方：

1.这里用了一个数组先收集好所有要DD（Darg&Drop，下同）的元素，再用for遍历new new YAHOO.util.DD()对象，“捆绑”成一类具有相同属性的对象：Draggable。

2.遇到一个无法入手的问题：
用YUI做Dragdrop，如果你的系统开clearType ，移动之后字体会发毛，估计ie内部render的问题。本来打算用DDProxy代替，但一用DDProxy就无法继承下去。

3.需手工加入xhtml的holder.

ok这个例子暂告一段落，看看一些好玩的(演示)：

复制代码代码如下:
var correct = { opt0:"ans1", opt1:"ans2", opt2:"ans0" }     // 正确答案
var answer  = { opt0:"tmp0", opt1:"tmp1", opt2:"tmp2" }     // 解答

// 採点
function mark(event)
{
    var points = 0;     //
    var max = 3;        //

    for (key in correct) {
        points += correct[key] == answer[key] ? 1: 0;
    }
    var score = Math.floor(points / max * 100);
    var result = document.getElementById("result");
    result.innerHTML = (score > 70 ? "合格": "不合格") + "：" + score + "%";
}

// 初始化
function init(event)
{

    var dropzone = [ "ans0", "ans1", "ans2",            // 答案栏
                     "tmp0", "tmp1", "tmp2" ];          // 临时地方（开始放国旗的地方）
    for (id in dropzone) {
        new YAHOO.util.DDTarget(dropzone[id]);
    }


    var draggable = [ "opt0", "opt1", "opt2" ];         // 可选项（国旗）

    Draggable = function(id, sGroup) {
        this.init(id, sGroup);
    }

    Draggable.prototype = new YAHOO.util.DD();

    Draggable.prototype.canAccept = function(draggable, dropzone) {
        if (dropzone.id.match(/^opt[012]$/)) {
            return false;
        }
        for (key in answer) {
            if (answer[key] == dropzone.id) {
                return false;
            }
        }
        return true;
    }

    Draggable.prototype.startDrag = function(x, y) {
        YAHOO.util.Dom.setStyle(this.getEl(), "opacity", 0.5);
    }

    Draggable.prototype.onDragEnter = function(e, id) {
        var dropzone = YAHOO.util.DDM.getElement(id);
        var draggable = this.getEl();
        if (this.canAccept(draggable, dropzone)) {
            dropzone.style.backgroundColor = "orange";
        }
    }

    Draggable.prototype.onDragOut = function(e, id) {
        var dropzone = YAHOO.util.DDM.getElement(id);
        dropzone.style.backgroundColor = "white";
    }

    Draggable.prototype.onDragDrop = function(e, id) {
        var dropzone = YAHOO.util.DDM.getElement(id);
        var draggable = this.getEl();
        if (this.canAccept(draggable, dropzone)) {
            dropzone.style.backgroundColor = "white";
            dropzone.appendChild(draggable);
            answer[draggable.id] = dropzone.id;         // 解答更新
        }
    }

    Draggable.prototype.endDrag = function(e) {
        var draggable = this.getEl();
        YAHOO.util.Dom.setStyle(draggable, "opacity", 1.0);
        draggable.style.left = "0px";
        draggable.style.top  = "0px";
    }

    for (id in draggable) {
        new Draggable(draggable[id]);
    }

    // 绑定按钮触发事件，计算成绩
    YAHOO.util.Event.addListener("submit", "click", mark);
}

YAHOO.util.Event.addListener(window, "load", init);

       如果再把xhtml贴出来，很长很烦。look look DEMO.

好，今天到这儿，严重ot中。有空再说。