由实例出发看看Ext——《Basic Array Grid》

于 2010-08-10 15:25:25 发布 · 173 阅读 · 0
文章标签：

#EXT #Microsoft #json #J#

本文介绍如何使用Ext JS创建一个简单的Grid组件，包括数据存储和列配置。通过实例展示了如何设置store和columns，以及自定义列渲染器。

使用Ext可以说最多的就是Grid了，它可以方便的展示列表数据并能够对数据分页和排序。

下面从最简单Grid例子开始——《Basic Array Grid》。

 

上截图和代码（这个例子也可以在Ext官方的例程列表中找到）

/*!
 * Ext JS Library 3.2.1
 * Copyright(c) 2006-2010 Ext JS, Inc.
 * licensing@extjs.com
 * http://www.extjs.com/license
 */
Ext.onReady(function(){

    // NOTE: This is an example showing simple state management. During development,
    // it is generally best to disable state management as dynamically-generated ids
    // can change across page loads, leading to unpredictable results.  The developer
    // should ensure that stable state ids are set for stateful components in real apps.    
    Ext.state.Manager.setProvider(new Ext.state.CookieProvider());

    // sample static data for the store
    var myData = [
        ['3m Co',71.72,0.02,0.03,'9/1 12:00am'],
        ['Alcoa Inc',29.01,0.42,1.47,'9/1 12:00am'],
        ['Altria Group Inc',83.81,0.28,0.34,'9/1 12:00am'],
        ['American Express Company',52.55,0.01,0.02,'9/1 12:00am'],
        ['American International Group, Inc.',64.13,0.31,0.49,'9/1 12:00am'],
        ['AT&T Inc.',31.61,-0.48,-1.54,'9/1 12:00am'],
        ['Boeing Co.',75.43,0.53,0.71,'9/1 12:00am'],
        ['Caterpillar Inc.',67.27,0.92,1.39,'9/1 12:00am'],
        ['Citigroup, Inc.',49.37,0.02,0.04,'9/1 12:00am'],
        ['E.I. du Pont de Nemours and Company',40.48,0.51,1.28,'9/1 12:00am'],
        ['Exxon Mobil Corp',68.1,-0.43,-0.64,'9/1 12:00am'],
        ['General Electric Company',34.14,-0.08,-0.23,'9/1 12:00am'],
        ['General Motors Corporation',30.27,1.09,3.74,'9/1 12:00am'],
        ['Hewlett-Packard Co.',36.53,-0.03,-0.08,'9/1 12:00am'],
        ['Honeywell Intl Inc',38.77,0.05,0.13,'9/1 12:00am'],
        ['Intel Corporation',19.88,0.31,1.58,'9/1 12:00am'],
        ['International Business Machines',81.41,0.44,0.54,'9/1 12:00am'],
        ['Johnson & Johnson',64.72,0.06,0.09,'9/1 12:00am'],
        ['JP Morgan & Chase & Co',45.73,0.07,0.15,'9/1 12:00am'],
        ['McDonald\'s Corporation',36.76,0.86,2.40,'9/1 12:00am'],
        ['Merck & Co., Inc.',40.96,0.41,1.01,'9/1 12:00am'],
        ['Microsoft Corporation',25.84,0.14,0.54,'9/1 12:00am'],
        ['Pfizer Inc',27.96,0.4,1.45,'9/1 12:00am'],
        ['The Coca-Cola Company',45.07,0.26,0.58,'9/1 12:00am'],
        ['The Home Depot, Inc.',34.64,0.35,1.02,'9/1 12:00am'],
        ['The Procter & Gamble Company',61.91,0.01,0.02,'9/1 12:00am'],
        ['United Technologies Corporation',63.26,0.55,0.88,'9/1 12:00am'],
        ['Verizon Communications',35.57,0.39,1.11,'9/1 12:00am'],            
        ['Wal-Mart Stores, Inc.',45.45,0.73,1.63,'9/1 12:00am']
    ];

    /**
     * Custom function used for column renderer
     * @param {Object} val
     */
    function change(val){
        if(val > 0){
            return '<span style="color:green;">' + val + '</span>';
        }else if(val < 0){
            return '<span style="color:red;">' + val + '</span>';
        }
        return val;
    }

    /**
     * Custom function used for column renderer
     * @param {Object} val
     */
    function pctChange(val){
        if(val > 0){
            return '<span style="color:green;">' + val + '%</span>';
        }else if(val < 0){
            return '<span style="color:red;">' + val + '%</span>';
        }
        return val;
    }

    // create the data store
    var store = new Ext.data.ArrayStore({
        fields: [
           {name: 'company'},
           {name: 'price', type: 'float'},
           {name: 'change', type: 'float'},
           {name: 'pctChange', type: 'float'},
           {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
        ]
    });

    // manually load local data
    store.loadData(myData);

    // create the Grid
    var grid = new Ext.grid.GridPanel({
        store: store,
        columns: [
            {id:'company',header: 'Company', width: 160, sortable: true, dataIndex: 'company'},
            {header: 'Price', width: 75, sortable: true, renderer: 'usMoney', dataIndex: 'price'},
            {header: 'Change', width: 75, sortable: true, renderer: change, dataIndex: 'change'},
            {header: '% Change', width: 75, sortable: true, renderer: pctChange, dataIndex: 'pctChange'},
            {header: 'Last Updated', width: 85, sortable: true, renderer: Ext.util.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
        ],
        stripeRows: true,
        autoExpandColumn: 'company',
        height: 350,
        width: 600,
        title: 'Array Grid',
        // config options for stateful behavior
        stateful: true,
        stateId: 'grid'        
    });
    
    // render the grid to the specified div in the page
    grid.render('grid-example');
});

Grid中有两个非常重要的属性，store和columns。store定义Grid需要展示的数据，columns定义Grid如何展示数据。在这个例子中主要也就是说说这两个属性如何设置。

 

store（仓库），没错它就是数据仓库（不是那个数据仓库@o@）。在这个例子中给store属性赋的是Ext.data.ArrayStore的实例，实际上看看Ext的API就会知道有很多种store（ArrayStore, DirectStore, GroupingStore, JsonStore, XmlStore），其实在我开发的过程中最常用的是JsonStore，也就是根据后台回传的Json来组织数据仓库，后面应该还会说到。在本例中就直说ArrayStore的事，ArrayStore看名字得知这个根据数组组织store的。

 

例子中给了数组的定义，如下：

    // sample static data for the store
    var myData = [
        ['3m Co',71.72,0.02,0.03,'9/1 12:00am'],
        ['Alcoa Inc',29.01,0.42,1.47,'9/1 12:00am'],
        ['Altria Group Inc',83.81,0.28,0.34,'9/1 12:00am'],
        ['American Express Company',52.55,0.01,0.02,'9/1 12:00am'],
        ['American International Group, Inc.',64.13,0.31,0.49,'9/1 12:00am'],
        ['AT&T Inc.',31.61,-0.48,-1.54,'9/1 12:00am'],
        ['Boeing Co.',75.43,0.53,0.71,'9/1 12:00am'],
        ['Caterpillar Inc.',67.27,0.92,1.39,'9/1 12:00am'],
        ['Citigroup, Inc.',49.37,0.02,0.04,'9/1 12:00am'],
        ['E.I. du Pont de Nemours and Company',40.48,0.51,1.28,'9/1 12:00am'],
        ['Exxon Mobil Corp',68.1,-0.43,-0.64,'9/1 12:00am'],
        ['General Electric Company',34.14,-0.08,-0.23,'9/1 12:00am'],
        ['General Motors Corporation',30.27,1.09,3.74,'9/1 12:00am'],
        ['Hewlett-Packard Co.',36.53,-0.03,-0.08,'9/1 12:00am'],
        ['Honeywell Intl Inc',38.77,0.05,0.13,'9/1 12:00am'],
        ['Intel Corporation',19.88,0.31,1.58,'9/1 12:00am'],
        ['International Business Machines',81.41,0.44,0.54,'9/1 12:00am'],
        ['Johnson & Johnson',64.72,0.06,0.09,'9/1 12:00am'],
        ['JP Morgan & Chase & Co',45.73,0.07,0.15,'9/1 12:00am'],
        ['McDonald\'s Corporation',36.76,0.86,2.40,'9/1 12:00am'],
        ['Merck & Co., Inc.',40.96,0.41,1.01,'9/1 12:00am'],
        ['Microsoft Corporation',25.84,0.14,0.54,'9/1 12:00am'],
        ['Pfizer Inc',27.96,0.4,1.45,'9/1 12:00am'],
        ['The Coca-Cola Company',45.07,0.26,0.58,'9/1 12:00am'],
        ['The Home Depot, Inc.',34.64,0.35,1.02,'9/1 12:00am'],
        ['The Procter & Gamble Company',61.91,0.01,0.02,'9/1 12:00am'],
        ['United Technologies Corporation',63.26,0.55,0.88,'9/1 12:00am'],
        ['Verizon Communications',35.57,0.39,1.11,'9/1 12:00am'],            
        ['Wal-Mart Stores, Inc.',45.45,0.73,1.63,'9/1 12:00am']
    ];

实际上这是一个二维数组，每一个第二维的子数组都是一条记录的定义，每条记录中有5个字段，整个数组是由这样的多个子数组组成。在定义ArrayStore实例时还给出了fields的定义。

    // create the data store
    var store = new Ext.data.ArrayStore({
        fields: [
           {name: 'company'},
           {name: 'price', type: 'float'},
           {name: 'change', type: 'float'},
           {name: 'pctChange', type: 'float'},
           {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
        ]
    });

    // manually load local data
    store.loadData(myData);

在fields中按照子数组的顺序定义了五个字段，并分别起好了名字，还定义了字段的数据类型，默认是字符串类型的，所以company没有单独声明数据类型。在store中还定义了许多属性和方法，会在后面的例子中慢慢说到。

在定义了store中，例子中还调用了loadData方法，将数据加载到仓库中。其实也可以在定义store时就将data定义好，后面就不用在写loadData了，如：

// create the data store
var store = new Ext.data.ArrayStore({
    fields: [
       {name: 'company'},
       {name: 'price', type: 'float'},
       {name: 'change', type: 'float'},
       {name: 'pctChange', type: 'float'},
       {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
    ],
    data: myData
});

columns（列），定义Grid显示的列。

columns: [
    {id:'company',header: 'Company', width: 160, sortable: true, dataIndex: 'company'},
    {header: 'Price', width: 75, sortable: true, renderer: 'usMoney', dataIndex: 'price'},
    {header: 'Change', width: 75, sortable: true, renderer: change, dataIndex: 'change'},
    {header: '% Change', width: 75, sortable: true, renderer: pctChange, dataIndex: 'pctChange'},
    {header: 'Last Updated', width: 85, sortable: true, renderer: Ext.util.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
],

在这个例子中是这样定义columns属性的，其实也可以像定义store一样来定义columns，先声明一个变量再赋值给columns，如：

var cols = [
    {id:'company',header: 'Company', width: 160, sortable: true, dataIndex: 'company'},
    {header: 'Price', width: 75, sortable: true, renderer: 'usMoney', dataIndex: 'price'},
    {header: 'Change', width: 75, sortable: true, renderer: change, dataIndex: 'change'},
    {header: '% Change', width: 75, sortable: true, renderer: pctChange, dataIndex: 'pctChange'},
    {header: 'Last Updated', width: 85, sortable: true, renderer: Ext.util.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
];

// create the Grid
var grid = new Ext.grid.GridPanel({
    store: store,
    columns: cols,
    …………
});

这里cols对应该数组Ext实际将其解析为Ext.grid.Column的对象，id定义当前字段是记录的标识，header定义表头显示的名字，width定义列宽，sortable定义是否允许以给列排序，dataIndex定义该列显示store中哪个字段，renderer定义显示该列要添加的格式。

 

renderer显示的格式，Ext在Ext.util.Format中已经定义不少格式化的方法，在本例中使用了usMoney（美元）和dateRenderer（日期），除了已经定义好的，开发人员也可以自定义格式，如change和pctChange。

/**
 * Custom function used for column renderer
 * @param {Object} val
 */
function change(val){
    if(val > 0){
        return '<span style="color:green;">' + val + '</span>';
    }else if(val < 0){
        return '<span style="color:red;">' + val + '</span>';
    }
    return val;
}

/**
 * Custom function used for column renderer
 * @param {Object} val
 */
function pctChange(val){
    if(val > 0){
        return '<span style="color:green;">' + val + '%</span>';
    }else if(val < 0){
        return '<span style="color:red;">' + val + '%</span>';
    }
    return val;
}

格式化方法接收一个参数，那就是要格式化的值，返回一个结果是格式化后的值。

 

在Grid的定义中还有：

autoExpandColumn: 'company',

这句话定义了列'company'是自动扩展列，会根据内容自动扩展给列的宽度

title: 'Array Grid',

定义整个列表的标题，如果不写该行，则列表（Grid）不显示标题。

height: 350,
width: 600,

定义Grid的高度和宽度

stateful: true,
stateId: 'grid'

当stateful为真时，保存当前列表的状态，如按照哪列排序、列宽、列的先后位置；stateId指明了保存状态的ID，若不指定该属性则无法保存列表状态。

 

例子的最后一行

grid.render('grid-example');

让表格显示在id为“grid-example”的div中。

 

本例打完收工。

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