提供了编程的基础技术教程

zl程序教程

您现在的位置是：首页 >  工具

当前栏目

extjs学习笔记（三）最基本的grid

笔记学习 基本 Extjs Grid
2023-06-13 09:14:13 时间
jquery在这方面则正好相反，它的UI都以插件形式提供，可以需要什么就引用什么，所以非常小巧灵活，但由于插件往往是由不同的人或者团队来提供，界面和接口往往就不那么一致。反正是各有千秋吧。
今天学习extjs中的grid，它可以说是功能强大，无出其右，只有你想不到的，没有它做不到的，呵呵，好像是有点夸张了。好，不说废话了，我们就从最简单的grid开始，一步步来看看extjs给我们提供的grid究竟给我们提供了哪些功能。
一个grid包括一些行和列，在extjs里边，列由Ext.grid.ColumnModel来管理，我们来看看如何创建一个ColumnModel对象：
复制代码代码如下:

varcm=newExt.grid.ColumnModel([
{id:"company",header:"Company",width:160,sortable:true,dataIndex:"company"},
{header:"Price",width:75,sortable:true,dataIndex:"price"},
{header:"Change",width:75,sortable:true,dataIndex:"change"},
{header:"%Change",width:75,sortable:true,dataIndex:"pctChange"},
{header:"LastUpdated",width:85,sortable:true,dataIndex:"lastChange"}
]);

这里定义了五个列,列可以通过参数进行配置：id用来标识列，在css中使用该id可以对整列所有的单元格设置样式，可自动扩充的列也根据这个id来标识；header是列名字；width是列的宽度;sortable用来指明列是否可排序，dataIndex，先不管它。比较常用的参数还有：editable，指示列是否可编辑；renderer，指示列如何来呈现，后边会再详细介绍它。
有了列，我们还需要一些数据来填充行，构造一个数组吧：
复制代码代码如下:

varmyData=[
["3mCo",71.72,0.02,0.03,"9/112:00am"],
["AlcoaInc",29.01,0.42,1.47,"9/112:00am"],
["AltriaGroupInc",83.81,0.28,0.34,"9/112:00am"],
["AmericanExpressCompany",52.55,0.01,0.02,"9/112:00am"],
["AmericanInternationalGroup,Inc.",64.13,0.31,0.49,"9/112:00am"],
["AT&TInc.",31.61,-0.48,-1.54,"9/112:00am"],
["BoeingCo.",75.43,0.53,0.71,"9/112:00am"],
["CaterpillarInc.",67.27,0.92,1.39,"9/112:00am"],
["Citigroup,Inc.",49.37,0.02,0.04,"9/112:00am"],
["E.I.duPontdeNemoursandCompany",40.48,0.51,1.28,"9/112:00am"],
["ExxonMobilCorp",68.1,-0.43,-0.64,"9/112:00am"],
["GeneralElectricCompany",34.14,-0.08,-0.23,"9/112:00am"],
["GeneralMotorsCorporation",30.27,1.09,3.74,"9/112:00am"],
["Hewlett-PackardCo.",36.53,-0.03,-0.08,"9/112:00am"],
["HoneywellIntlInc",38.77,0.05,0.13,"9/112:00am"],
["IntelCorporation",19.88,0.31,1.58,"9/112:00am"],
["InternationalBusinessMachines",81.41,0.44,0.54,"9/112:00am"],
["Johnson&Johnson",64.72,0.06,0.09,"9/112:00am"],
["JPMorgan&Chase&Co",45.73,0.07,0.15,"9/112:00am"],
["McDonald\"sCorporation",36.76,0.86,2.40,"9/112:00am"],
["Merck&Co.,Inc.",40.96,0.41,1.01,"9/112:00am"],
["MicrosoftCorporation",25.84,0.14,0.54,"9/112:00am"],
["PfizerInc",27.96,0.4,1.45,"9/112:00am"],
["TheCoca-ColaCompany",45.07,0.26,0.58,"9/112:00am"],
["TheHomeDepot,Inc.",34.64,0.35,1.02,"9/112:00am"],
["TheProcter&GambleCompany",61.91,0.01,0.02,"9/112:00am"],
["UnitedTechnologiesCorporation",63.26,0.55,0.88,"9/112:00am"],
["VerizonCommunications",35.57,0.39,1.11,"9/112:00am"],
["Wal-MartStores,Inc.",45.45,0.73,1.63,"9/112:00am"]
];

现在万事俱备只欠东风了，列定义好了，数据也有了，接下来就是把它们组装成一个grid。看一下完整的代码：
复制代码代码如下:
///<referencepath="vswd-ext_2.0.2.js"/>
/**//*
*作者：大笨
*日期：2009-10-13
*版本：1.0
*/
Ext.onReady(function(){
//构造列
varcm=newExt.grid.ColumnModel([
{id:"company",header:"Company",width:160,sortable:true,dataIndex:"company"},
{header:"Price",width:75,sortable:true,dataIndex:"price"},
{header:"Change",width:75,sortable:true,dataIndex:"change"},
{header:"%Change",width:75,sortable:true,dataIndex:"pctChange"},
{header:"LastUpdated",width:85,sortable:true,dataIndex:"lastChange"}
]);
//构造数据
varmyData=[
["3mCo",71.72,0.02,0.03,"9/112:00am"],
["AlcoaInc",29.01,0.42,1.47,"9/112:00am"],
["AltriaGroupInc",83.81,0.28,0.34,"9/112:00am"],
["AmericanExpressCompany",52.55,0.01,0.02,"9/112:00am"],
["AmericanInternationalGroup,Inc.",64.13,0.31,0.49,"9/112:00am"],
["AT&TInc.",31.61,-0.48,-1.54,"9/112:00am"],
["BoeingCo.",75.43,0.53,0.71,"9/112:00am"],
["CaterpillarInc.",67.27,0.92,1.39,"9/112:00am"],
["Citigroup,Inc.",49.37,0.02,0.04,"9/112:00am"],
["E.I.duPontdeNemoursandCompany",40.48,0.51,1.28,"9/112:00am"],
["ExxonMobilCorp",68.1,-0.43,-0.64,"9/112:00am"],
["GeneralElectricCompany",34.14,-0.08,-0.23,"9/112:00am"],
["GeneralMotorsCorporation",30.27,1.09,3.74,"9/112:00am"],
["Hewlett-PackardCo.",36.53,-0.03,-0.08,"9/112:00am"],
["HoneywellIntlInc",38.77,0.05,0.13,"9/112:00am"],
["IntelCorporation",19.88,0.31,1.58,"9/112:00am"],
["InternationalBusinessMachines",81.41,0.44,0.54,"9/112:00am"],
["Johnson&Johnson",64.72,0.06,0.09,"9/112:00am"],
["JPMorgan&Chase&Co",45.73,0.07,0.15,"9/112:00am"],
["McDonald\"sCorporation",36.76,0.86,2.40,"9/112:00am"],
["Merck&Co.,Inc.",40.96,0.41,1.01,"9/112:00am"],
["MicrosoftCorporation",25.84,0.14,0.54,"9/112:00am"],
["PfizerInc",27.96,0.4,1.45,"9/112:00am"],
["TheCoca-ColaCompany",45.07,0.26,0.58,"9/112:00am"],
["TheHomeDepot,Inc.",34.64,0.35,1.02,"9/112:00am"],
["TheProcter&GambleCompany",61.91,0.01,0.02,"9/112:00am"],
["UnitedTechnologiesCorporation",63.26,0.55,0.88,"9/112:00am"],
["VerizonCommunications",35.57,0.39,1.11,"9/112:00am"],
["Wal-MartStores,Inc.",45.45,0.73,1.63,"9/112:00am"]
];
//构造grid
vargrid=newExt.grid.GridPanel({
renderTo:"grid",
store:newExt.data.ArrayStore({
fields:[
{name:"company"},
{name:"price",type:"float"},
{name:"change",type:"float"},
{name:"pctChange",type:"float"},
{name:"lastChange",type:"date",dateFormat:"n/jh:ia"}
],
data:myData
}),
cm:cm,
stripeRows:true,
autoExpandColumn:"company",
height:350,
width:600,
title:"ArrayGrid"
});
})

在extjs中，Ext.grid.GridPanel表示一个grid，它需要一个json对象作为参数来进行配置，我们看看用到的配置：
renderTo：指出grid构造出来之后要在哪里呈现，可以是一个元素的id，一个Dom结点或者一个Element对象，如果没有这个参数，就必须调用Ext.grid.GridPanel的render方法来呈现出grid。
stroe：可以简写为ds，以一个统一的接口提供数据给grid，，我们知道数据可能有很多种格式，除了我们用到的数组，还可以是json,xml等等，如果让grid负责来识别每一种数据格式显然不是一个好的设计思想，所以在extjs中有一个专门的类Ext.data.Store来负责数据的格式转换，这里我们用到它的子类ArrayStore，顾名思义，是专门针对数组来进行转换的。我们会专门有一个系列来讨论Ext.data命名空间下边的一些类，那时会对Store类进行深入的了解。现在我们只看看我们用到的fields字段，它是Ext.data.Field类的集合，该类有一个name属性，我们前边在ColumnModel里边置之不理的dataIndex就是引用了这个属性的值来对应列和Field之间的关系，type用来指出类型，默认是字符串类型，dateFormat则指出日期的格式。
cm：colModel的简写，这里放上我们前边构造好的ColumnModel对象就可以了。
stripeRows：是否显示条纹。
autoExpandColumn：自动扩充的列，该列会自动填充grid的空白空间。
height和width：grid的高度和宽度。
title：grid的标题。
现在我们运行一下看看效果，应该说这个grid还算漂亮，在列的名字上点击还能够进行排序，列的宽度可以自由拖动，位置也可以改变。按下ctrl键，我们可以选择多个行。当我们把鼠标移动到列名上，还可以看到出现一个倒立的小三角，点击出现个菜单，可以看到里边能对列进行排序，还可以隐藏列。不过我们也看到，日期的显示并不尽如人意，百分比依然是浮点数，而且我们通常用赤字表示亏损或者现在更为流行的说法负增长，如果在我们的grid里边，负增长也可以用赤字表现出来，效果应该会更好一些。extjs给我们提供了一个很方便的东西来实现我们的想法：renderer。在ColumnModel里边，我们可以给需要的列里边增加renderer来实现我们想要的效果。下边是改动后的ColumnModel:
复制代码代码如下:
//构造列
varcm=newExt.grid.ColumnModel([
{id:"company",header:"Company",width:160,sortable:true,dataIndex:"company"},
{header:"Price",width:75,sortable:true,dataIndex:"price"},
{header:"Change",width:75,sortable:true,dataIndex:"change",renderer:change},
{header:"%Change",width:75,sortable:true,dataIndex:"pctChange",renderer:pctChange},
{header:"LastUpdated",width:120,sortable:true,dataIndex:"lastChange",renderer:Ext.util.Format.dateRenderer("Y-m-dh:i")}
]);
//Change列的renderer函数
functionchange(val){
if(val>0){
return"<spanstyle="color:green;">"+val+"</span>";
}elseif(val<0){
return"<spanstyle="color:red;">"+val+"</span>";
}
returnval;
}
//%Change列的renderer函数
functionpctChange(val){
if(val>0){
return"<spanstyle="color:green;">"+val+"%</span>";
}elseif(val<0){
return"<spanstyle="color:red;">"+val+"%</span>";
}
returnval;
}

renderer可以理解为一个“解释器”方法，它用来在显示数据之前转化数据。可以有三种方式来实现renderer：
使用一个返回HTML标记的renderer函数
Ext.util.Format类的一个属性，该属性提供一个renderer函数
一个包括renderer函数和作用域的对象
我们的例子用到了前两种方式。renderer函数传递6个参数，保存了单元格的所有信息，这里只用到了第一个参数，它保存了单元格的值，其它参数的意义我们可以参考帮助文档。
现在运行程序，可以看到我们希望的效果了：负增长用了赤字来表示，作为对比，正的增长用了绿颜色，时间也按照我们希望的格式显示了出来。
有的时候，我们还希望给每一行编号，这个实现起来也很容易，我们只要在ColumnModel的构造函数里边加上newExt.grid.RowNumberer()就可以了：
复制代码代码如下:
varcm=newExt.grid.ColumnModel([
newExt.grid.RowNumberer(),//实现自动编号
{id:"company",header:"Company",width:160,sortable:true,dataIndex:"company"},
{header:"Price",width:75,sortable:true,dataIndex:"price"},
{header:"Change",width:75,sortable:true,dataIndex:"change",renderer:change},
{header:"%Change",width:75,sortable:true,dataIndex:"pctChange",renderer:pctChange},
{header:"LastUpdated",width:120,sortable:true,dataIndex:"lastChange",renderer:Ext.util.Format.dateRenderer("Y-m-dh:i")}
]);

Ext.grid.GridPanel的配置里边还有两个常用的参数：
viewConfig：我们可以用这个参数来对grid的界面进行一些设置，详细内容可以查看帮助文档。
selModel：可以简写为sm，选择模型，比如是选择单元格还是选择整个行，默认是选择行。

相关文章