在我们国内开发应用系统的过程中往往会遇到这样的需求:下拉菜单中的条目过多时,用户在筛选时往往非常费劲,希望能提供条目拼音简码的方式进行筛选,加快选择速度。而Dojo的FilteringSelect是个非常优秀的具有动态筛选及autoComplete的下拉菜单组件,我们尝试用它来实现一个具有拼音检索功能的下拉菜单。我们以一个三国人物选择的下拉菜单为例看看FilteringSelect的使用,注意demo使用的是dojo的1.8版本。
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>下拉菜单</title> <link rel="stylesheet" href="static/js/dojo/dojo/resources/dojo.css" /> <link rel="stylesheet" href="static/js/dojo/dijit/themes/claro/claro.css" /> <script type="text/javascript" src="static/js/dojo/dojo/dojo.js" data-dojo-config="async: true,parseOnLoad: true"></script> <script type="text/javascript"> require([ 'dijit/form/FilteringSelect', 'dojo/store/Memory', 'dojo/domReady!' ],function(FilteringSelect,Memory){ //下拉菜单的store,"py"字段存放每个条目的拼音简码 var selectStore = new Memory({ data:[ {name:'赵云',id:'1',py:'zy'}, {name:'张飞',id:'2',py:'zf'}, {name:'刘备',id:'3',py:'lb'}, {name:'关羽',id:'4',py:'gy'}, {name:'黄忠',id:'5',py:'hz'}, {name:'魏延',id:'6',py:'wy'}, {name:'周瑜',id:'7',py:'zy'}, {name:'孙坚',id:'8',py:'sj'}, {name:'曹操',id:'9',py:'cc'}, {name:'夏侯敦',id:'10',py:'xhd'}, ] }); //创建FilteringSelect var testSelect = new FilteringSelect({ id: "testSelect", name: "test", value: "", store: selectStore, searchAttr: 'py',//指定输入文本框进行用来进行检索的字段 labelAttr: 'name',//指定下拉菜单中显示的字段 required:false, autoComplete:false },"testSelect"); }); </script> </head> <body class="claro"> <div style="text-align: center;width: 100%;padding-top: 100px;font-size:15px;"> 三国人物:<input id="testSelect"/> </div> </body> </html>运行页面,在下拉菜单输入框中输入“zy”,发现下拉菜单已经可以根据输入的拼音简码进行过滤了,如下图:
这时,问题来了,你会发现当鼠标选定下拉菜单中条目,如选“周瑜”时,最终在输入框中呈现的并不是我们想要的中文名称“周瑜”而是该条目对应的py字段的值“zy”。这是因为FilteringSelect会以searchAttr属性中设置的字段作为最终显示结果。但这并不是我们想要的结果,我们希望显示的是中文的name字段。
经过翻看FilteringSelect的源码,发现可以对FilteringSelect进行一下小的改造来满足我们的要求。可以使用Dojo提供的自定义组件机制,通过继承FilteringSelect来创建一个满足我们需求的FilteringSelect组件。代码如下:
define([ "dojo/_base/declare", // declare, "dojo/dom-attr", // domAttr.get "dijit/form/FilteringSelect" ], function(declare, domAttr ,FilteringSelect){ return declare("test.FilteringSelect", [FilteringSelect], { displayValueAttr:null, //新增一个自定义属性,用于指定FilteringSelect的textbox中最终显示内容的属性字段 // summary: // 覆盖dijit.form._AutoCompleterMixin的同名方法,使FilteringSelect支持displayValueAttr指定textbox最终显示内容,而不是默认显示searchAttr指定的字段内容 _announceOption: function(/*Node*/ node){ if(!node){ return; } // pull the text value from the item attached to the DOM node var newValue; if(node == this.dropDown.nextButton || node == this.dropDown.previousButton){ newValue = node.innerHTML; this.item = undefined; this.value = ''; }else{ var item = this.dropDown.items[node.getAttribute("item")]; var displayAttr = this.displayValueAttr!=null?this.displayValueAttr:this.searchAttr;//此处判断是否配置了自定义属性displayValueAttr newValue = (this.store._oldAPI ? // remove getValue() for 2.0 (old dojo.data API) this.store.getValue(item, displayAttr) : item[displayAttr]).toString();//将this.searchAttr替换为displayAttr this.set('item', item, false, newValue); } // get the text that the user manually entered (cut off autocompleted text) this.focusNode.value = this.focusNode.value.substring(0, this._lastInput.length); // set up ARIA activedescendant this.focusNode.setAttribute("aria-activedescendant", domAttr.get(node, "id")); // autocomplete the rest of the option to announce change this._autoCompleteText(newValue); }, }); });将页面中引入FilteringSelect换成我们自定义的FilteringSelect,然后在创建FilteringSelect时的代码中加入自定义的displayValueAttr属性。
<script type="text/javascript"> require([ 'test/FilteringSelect', 'dojo/store/Memory', 'dojo/domReady!' ],function(FilteringSelect,Memory){ //下拉菜单的store,"py"字段存放每个条目的拼音简码 var selectStore = new Memory({ data:[ {name:'赵云',id:'1',py:'zy'}, {name:'张飞',id:'2',py:'zf'}, {name:'刘备',id:'3',py:'lb'}, {name:'关羽',id:'4',py:'gy'}, {name:'黄忠',id:'5',py:'hz'}, {name:'魏延',id:'6',py:'wy'}, {name:'周瑜',id:'7',py:'zy'}, {name:'孙坚',id:'8',py:'sj'}, {name:'曹操',id:'9',py:'cc'}, {name:'夏侯敦',id:'10',py:'xhd'}, ] }); //创建FilteringSelect var testSelect = new FilteringSelect({ id: "testSelect", name: "test", value: "", store: selectStore, searchAttr: 'py',//指定输入文本框进行用来进行检索的字段 labelAttr: 'name',//指定下拉菜单中显示的字段 displayValueAttr:'name',//指定选中下拉菜单后显示在输入框中的字段 required:false, autoComplete:false },"testSelect"); }); </script>再次访问本页面,可以看到在选择下拉菜单条目后,text输入框显示为name的中文了。
下篇预告:
准备写一下服务端自动实现新增实体bean时,将相应name字段转为拼音简码后存储。大致过程是编写一个java注解,在model实体类中标注需要进行汉字转拼音的属性字段,利用spring的AOP功能,编写一个统一切面,在dao层对保存实体的save方法进行拦截,将标注的name字段转为拼音简码后注入bean的拼音简码字段,这样使业务编码人员无需再关注对实体name字段进行拼音简码的转换工作。