可拖拽的tree实际应用
ext提供的树本身就有拖拽的功能，也许大部分使用过TreePanel的都知道。可是光是在前台拖来拖去那是空把式不是吗？因此必须获取拖拽的事件才能与后台交互。因此现在就说一下如何获取tree的拖拽事件。
对于要想让tree可以拖拽，那么必须为tree的enableDD属性设置为true。
其实事件最常用的就是nodedrop。eg：tree.on('nodedrop',function(){ …… });
js代码：
//节点可以编辑的树
Ext.namespace('demo');
demo = function(){
this.init();//初始化函数
};
Ext.extend(demo,Ext.util.Observable,{
init:function(){
//创建一个简写
var Tree = Ext.tree;
//添加一个树形面板
this.tree = new Tree.TreePanel({
el:'tree-panel',//将树形添加到一个指定的div中
title:'可编辑的树',
autoScroll:true,
enableDD:true,//是否支持拖拽效果
containerScroll: true,//是否支持滚动条
loader:new Ext.tree.TreeLoader({
dataUrl:'tree-tz-test.json'
})
});
//创建一个根节点
this.root = new Tree.AsyncTreeNode({
text: '木叶村',
draggable:false,
id:'source'
});
//为tree设置根节点
this.tree.setRootNode(this.root);
//渲染树形
this.tree.render();
this.root.expand(true);
/*设置tree的节点放置函数此函数有一个很重要的参数对象e
e对象有三个重要的属性，分别为dropNode,target,point
1.dropNode为在拖动时鼠标抓住的节点
2.target为将要放置在某处的节点
3.point为被放置的状态，分别有append表示添加，above节点的上方，below节点的下方。
*/
this.tree.on('nodedrop',function(e){
if(e.point=='append'){
alert('当前"'+e.dropNode.text+'"被"'+e.target.text+'"录取！');
}else if(e.point=='above'){
alert('当前"'+e.dropNode.text+'"放在了"'+e.target.text+'"上面！');
}else if(e.point=='below'){
alert('当前"'+e.dropNode.text+'"放在了"'+e.target.text+'"下面！');
}
});
}
});
//实例化主程序类
Ext.BLANK_IMAGE_URL = 'images/public/s.gif"';
Ext.onReady(function(){
var myDemo = new demo(); //实例化
});
html：
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>可拖拽的树</title>
<link rel="shortcut icon" href="favicon.ico" />
<link rel="Bookmark" href="favicon.ico" />
<link href="css/default.css" rel="stylesheet" type="text/css">
<!--导入prototype文件 -->
<script language="javascript" type="text/javascript" src="js/prototype.js"></script>
</head>
<body>
<!--loading加载 -->
<div id="loadingTab">
<div class="loading-indicator">
<img src="images/public/loader.gif" width="32" height="32" style="margin-right:8px;float:left;vertical-align:top;"/>
<a href="index.html">可拖拽的树练习</a> -
<span id="loading-yfo"><a href="http://yfoffice.net.cn" target="_blank">忆凡工作室</a></span><br />
<span id="loading-msg">加载样式表和图片...</span>
</div>
</div>
<br>
<h1>拖拽tree的综合练习</h1>
<div id="tree-panel" style=" margin:30px; width:300px; height:400px"></div>
<link href="js/ext-2.0/resources/css/ext-all.css" rel="stylesheet" type="text/css">
<script type="text/javascript">$('loading-msg').innerHTML = '正在加载JSUI组建...';</script>
<script language="javascript" type="text/javascript" src="js/ext-2.0/adapter/ext/ext-base.js"></script>
<script language="javascript" type="text/javascript" src="js/ext-2.0/ext-all.js"></script>
<script language="javascript" type="text/javascript" src="js/ext-2.0/source/locale/ext-lang-zh_CN.js"></script>
<script type="text/javascript">$('loading-msg').innerHTML = '正在初始化...';</script>
<script type="text/javascript" src="js/tree-tz-test.js"></script>
<script type="text/javascript">
$('loading-msg').innerHTML = '初始化完毕！！';
Ext.get('loadingTab').fadeOut({remove: true});//让加载标签消失
</script>
</body>
</html>
本例子的json：
[
{
"text":"卡卡西班",
"id":"01",
"allowDrag":false,
"children":[
{"text":"小樱","id":"0101","leaf":true,"allowDrag":true},
{"text":"鸣人","id":"0102","leaf":true,"allowDrag":true},
{"text":"佐助","id":"0103","leaf":true,"allowDrag":true}
]
},
{
"text":"凯班",
"id":"02",
"allowDrag":false,
"children":[
{"text":"小李","id":"0201","leaf":true,"allowDrag":true},
{"text":"宁次","id":"0202","leaf":true,"allowDrag":true},
{"text":"天天","id":"0203","leaf":true,"allowDrag":true}
]
}
]
看看上面json可以看出，我为节点设置了一个allowDrag属性，如果该属性为false，表示这个节点不可以拖动，否则可以.