EXTJS动态载入组件定义文件并初始化组件,动态构造界面的方法.

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先声明,动态载入的是一个类定义文件,比如,你扩展的窗口或诸如此类,可以很复杂,比如像我这样,就是某个界面.

难点在于:

使和ajax.request请求得到的脚本文件,被eval后,再用new产生组件,但问题在于这个生成的组件,却是无法传递出Request范围的,这是很郁闷的事,不然的话,就顺理成章的多.

Ext.ajax.request的返回值是无法改变的,应在Success回调函数中来运行组件文件,并生成组件.

很多人试着想把success回调函数中生成的值赋给全局变量,这样,就相当于把AJAX.REQUEST中一些结果带出来了.但事实上,经过N百回测试,以及GOOGLE搜索,问的人多,答案就没有,EXT官网和一些外国技术站点里,也没有人给出答案.

幸好JS有一个东东,Callback函数,这玩意真像C的函数指针,你把一个函数赋给一个变量,然后就可以用它来调用,并且传递参数给它,让这个回调函数做一些操作.问题就在这儿了,关键是,这个回调函数可以是另一个模块中定义的,这就妙了.

我的LoadModule函数就用了这点,LoadModule的调用者,传递一个container和一个回调函数,Loadmodule生成组件,并将其加入到container中,同时,将生成的组件作为参数Post给调用者提供的回调函数,这样,调用者就可以根据需要做一些操作,我的代码中,用loadmodule生成一个panel,将其加入到tabpanel中,而回调函数则将此panel设为活动的.整个过程中,调用者和被调用者保持了各自的独立性.

LoadModule方法:

 

    Ext.apply(Ext, {
        loadModule: function(config){            
            var container = config.container;
            var url = config.url;
            var params = config.params ||{};
            var myMask = new Ext.LoadMask(Ext.getBody(), {
                msg: "Loading..."
            });
            
            myMask.show();
            
            Ext.Ajax.request({
                method: 'GET',
                disableCaching: true,
                url: url,
                success: function(response){
                    var module = eval(response.responseText);
                    var comp = new module(params);
                    container.add(comp);
                    //回调函数,得到该组件
                    if (config.callBack) 
                            config.callBack(comp);
                },
                failure: function(response){
                
                    Ext.MessageBox.alert("Error", "Load Module Failure!");
                },
                scope: this
            });
            myMask.hide();           
        }
    });
    

 

某个自定义组件代码

category_UI = Ext.extend(Ext.Panel, {
    constructor: function(config){
        config = config ||
        {};
        category_UI.superclass.constructor.call(this, config);
    },
    
    initComponent: function(){
        var datastore = new Ext.data.JsonStore({
            url: "/data/category.asp",
            requestMethod: "GET",
            root: "data.records",
            remoteSort: false,
            autoLoad: true,
            totalProperty: "data.total",
            idProperty: "id",
            sortInfo: {
                field: "id",
                direction: "DESC"
            },
            fields: [{
                name: "id",
                type: "int"
            }, {
                name: "name"
            }, {
                name: "type"
            }, {
                name: "description"
            }]
        });
        
        
        
        var grid = new Ext.grid.GridPanel({
            store: datastore,
            enableDragDrop: false,
            border: false,            
            iconCls: "icon-grid",
            autoHeight: true,
            autoWidth: true,
            header: false,
            frame: false,            
            initload: true,
            autoExpandColumn: "Description",
            loadMask: true,
            layout: 'fit',
            viewConfig: {
                forceFit: true,
                emptyText: "No Records"
            },
            bbar: [{
                xtype: "button",
                text: "New Category",
                enableToggle: false,
                handler: function(btn, e){
                
                }
            }],
            columns: [{
                header: "ID",
                sortable: true,
                dataIndex: "id",
                hideable: false,
                width: 40
            }, {
                header: "Category",
                sortable: true,
                dataIndex: "name",
                hideable: false,
                width: 80
            }, {
                header: "Type",
                sortable: true,
                dataIndex: "type",
                width: 80,
                hideable: true
            }, {
                header: "Description",
                sortable: true,
                dataIndex: "description",
                hideable: false
            }],
            stripeRows: true
        });
        Ext.apply(this, {
            items: [grid]
        });
        category_UI.superclass.initComponent.call(this, arguments);
        
    }
});

 

 

动态构造界面范例

 

Ext.onReady(function(){

    Ext.QuickTips.init();
    
    //构造右侧主界面
    var tabs = new Ext.TabPanel({
        xtype: "tabpanel",
        region:"center",
        activeTab: 0,
        margins: "5 5 5 0",
        deferredRender: false,
        contextmenu: false,
        layoutOnTabChange: true,
        listeners: {
            "contextmenu": function(tabpanel, tab, e){
                if (!this.contextmenu) {
                    this.contextmenu = new Ext.menu.Menu([{                        
                        text: 'Close',
                        handler: function(){
                            if (tabs.ctxItem.closable)
                                tabs.remove(tabs.ctxItem);
                        }
                        
                    }, {                       
                        text: 'Close Other',
                        handler: function(){
                            tabs.items.each(function(item){
                                if (item.closable && item != tabs.ctxItem) 
                                    tabs.remove(item);
                            });
                        }
                    }]);
                }
                e.stopEvent();
                this.ctxItem = tab;
                this.contextmenu.showAt(e.getPoint());
            }
        },
        items: [{
            id: "help",
            title: "Overview",
            closable: false,
            autoHeight: true,
            autoLoad: {
                url: "/ui/help/",
                scripts: true,
                timeout: 90,
                nocache: false
                
            }
        }]
    });
    
    var mainMenu = new Ext.tree.TreePanel({        
        region: "west",        
        width: 180,
        minSize:160,
        maxSize:200,
        margins: "5 0 5 5",
        title: 'Menu',
        rootVisible: false,
        lines: true,
        autoScroll: true,
        singleExpand: false,
        useArrows: true,
        loader: {url: '/data/menu.asp',requestMethod:"GET"},
        root: new Ext.tree.AsyncTreeNode({expanded:true}),
        listeners: {
            "click": function(node, event){
                event.stopEvent();
                var href = node.attributes["href"];
                if (href != undefined && node.leaf) {
                    Ext.loadModule({
                        container: tabs,
                        url: href + "index.asp",
                        params: {
                            id: "view" + node.id,
                            title: node.text,
                            container: tabs,
                            closable:true,
                            autoHeight:true,
                            autoWidth:true,
                            border:false,
                            frame:false
                        },
                        callBack:function(ctrl)
                        {
                            tabs.setActiveTab(ctrl);
                            s=ctrl;
                        }
                    });
                    tabs.doLayout();
                }
            }
            
        }
    });
    
    var mainView = new Ext.Viewport({
        layout: "border",
        title: "Document Control System",
        autoHeight: true,
        autoWidth: true,
        defaults: {            
            split: true
        },
        items: [mainMenu, tabs],
        renderTo: Ext.getBody()
    });

    mainMenu.expandAll();

 })