dojo1.8树组件使用

dojo树组件现在有两个分支，第一个分支是使用旧store，遵循dojo的data API（该API已经不建议使用,存在于dojo/data文件夹中，但是没办法有的组件还真得用），另一个分支是使用新store，遵循dojo的store API（该API参考IndexDB API，存在于dojo/store文件夹中）。接下来要研究的是第二种情况，由于dojo tree组件还没有完全改写为dojo2.0风格，所以使用过程中也许会有一点别扭。

创建一棵最简单的树需要如下几个环节：
1、创建一个store，并为其实现getChildren方法（获取指定节点的子节点，数据层面）。
2、使用刚刚创建的store创建一个Model，Model只能是ObjectStoreModel（我们用新store嘛）。创建Model的时候一定要指定一个query配置项，该配置项决定了树的根，根必须是唯一。
3、使用Model创建Tree。
4、调用Tree的startup方法， 这一步根据实际情况决定是否需要。
5、happy！！！


如下是一个简单的示例，需要说明的是：

1、模拟数据在当前目录下的treedata.json中，使用dojo/text插件加载。

2、我使用的是chrome所以JSON是内置的全局属性。

3、模拟数据为

[{"id":"world","name":"The earth","type":"planet","population":"6 billion"},{"id":"AF","name":"Africa","type":"continent","population":"900 million","area":"30,221,532 sq km","timezone":"-1 UTC to +4 UTC","parent":"world"},{"id":"EG","name":"Egypt","type":"country","parent":"AF"},{"id":"KE","name":"Kenya","type":"country","parent":"AF"},{"id":"Nairobi","name":"Nairobi","type":"city","parent":"KE"},{"id":"Mombasa","name":"Mombasa","type":"city","parent":"KE"},{"id":"SD","name":"Sudan","type":"country","parent":"AF"},{"id":"Khartoum","name":"Khartoum","type":"city","parent":"SD"},{"id":"AS","name":"Asia","type":"continent","parent":"world"},{"id":"CN","name":"China","type":"country","parent":"AS"},{"id":"IN","name":"India","type":"country","parent":"AS"},{"id":"RU","name":"Russia","type":"country","parent":"AS"},{"id":"MN","name":"Mongolia","type":"country","parent":"AS"},{"id":"OC","name":"Oceania","type":"continent","population":"21 million","parent":"world"},{"id":"EU","name":"Europe","type":"continent","parent":"world"},{"id":"DE","name":"Germany","type":"country","parent":"EU"},{"id":"FR","name":"France","type":"country","parent":"EU"},{"id":"ES","name":"Spain","type":"country","parent":"EU"},{"id":"IT","name":"Italy","type":"country","parent":"EU"},{"id":"NA","name":"North America","type":"continent","parent":"world"},{"id":"SA","name":"South America","type":"continent","parent":"world","checked":"true"}]

require(["dojo/store/Memory", "dijit/Tree", "dijit/tree/ObjectStoreModel", "dojo/text!./treedata.json"],function(Memory, Tree, ObjectStoreModel, data){
	var data = data.replace(/[\n\r\t]/g, "");
	var treeData = JSON.parse(data);

	var myStore = new Memory({ // 创建store
		data : treeData,
        getChildren: function(object){ // 实现getChildren方法
            return this.query({parent: this.getIdentity(object)});
        } 
	});

	var treeModel = new ObjectStoreModel({ // 使用store创建model
		store: myStore,
		query: {id: 'world'}
	});
	var tree = new Tree({ // 创建树
		id : "tree", // 树id，可以根据该id使用registry模块的byId方法获取组件对象。
		model : treeModel, 
		// dndController: dndSource, // 节点间拖拽需要，还需要其他代码配合，此处并未实现拖拽
		showRoot : false, // 是否显示树根
		//openOnClick : true, // 单击展开
		persist: false,  // 持久化到cookie，记住上次打开树时候的状态
		// autoExpand : true, // 自动展开所有层次的节点
		//openOnDblClick : true // 双击展开
	}, 'treeDiv');

	tree.startup();
});	

到此简单的树就完成了，其他的功能就需要大家阅读文档了。文档地址为http://dojotoolkit.org/reference-guide/1.8/dijit/Tree.html#dijit-tree顺便还能看看More examples。