用类与原型写一个组件（三）--学习笔记_html/css

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用类与原型写一个组件（三）--学习笔记_html/css_WEB-ITnose

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Jun 21, 2016 am 09:00 AM

上一篇中，我们为组件添加了“删除一条item”的功能，现在，再增加一个“增加一条item”的功能。

首先，在页面中增加一个按钮，用来触发添加功能（红框中的内容是对比上一篇新加的代码）。

在main.js中绑定按钮的单击事件，触发add函数。

再在smartList.js里写add函数。

 1   // 增加一条数据 2   SmartList.prototype.add = function (data) { 3  4     var isExist = false; 5  6     // 判断id是否已存在 7     $.each(this.list, function (i, val) { 8       if (val.id === data.id) { 9         isExist = true;10         return false; // 退出循环11       }12     });13 14     if (isExist) {15       console.log('SmartList: id ' + data.id + ' 已存在，无法添加');16       return;17     }18 19     this.list.push(data);20     this._genItem(data).appendTo(this.element);21   };

现在可以注意到，$.each(this.list, function (i, val) {...}这行代码重复了，在add里用到了，在remove里也用到了，所以，我们是否可以写一个函数来代替这段重复的代码呢？于是，写一个_getById方法如下：

 1   SmartList.prototype._getById = function (id, callback) { 2     var self = this; 3     var data = null; 4  5     $.each(this.list, function (i, val) { 6       if (val.id === id) { 7         data = val; 8         if (callback && typeof callback === 'function') 9           callback(i, data);10         return false;11       }12     });13 14     return data;15   };

现在可以用_getById方法来改写remove和add方法。改写前后对比如下：

完整代码如下：

index.html:

 1 <html> 2 <head> 3   <meta charset="UTF-8"> 4   <title>Flexx</title> 5   <link href="http://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet"> 6   <link rel="stylesheet" href="./css/main.css"> 7   <script src="http://apps.bdimg.com/libs/jquery/2.0.0/jquery.min.js"></script> 8   <script src="http://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script> 9   <script src="./js/flexx.js"></script>10   <script src="./js/smartList.js"></script>11   <script src="./js/main.js"></script>12 </head>13 <body>14   <div class="container">15     <h1 id="Flexx-Library">Flexx Library</h1>16     <hr>17     <div class="row">18       <div class="col-xs-6">19         <div class="row">20           <div class="col-xs-12">21             <button id="btnAdd" class="btn btn-success">22                <i class="glyphicon glyphicon-plus"></i> 23             </button>24           </div>25         </div>26         <br>27         <div id="memberList"></div>28       </div>29       <div class="col-xs-6">30         <div id="groupList"></div>31       </div>32     </div>33   </div>34 </body>35 </html>View Code

smartList.js:

  1 /**  2  * SmartList  3  *  4  * 数据源：id为必须项  5  */  6   7 + function (Flexx) {  8   'use strict';  9  10   // 定义一个SmartList类 11   function SmartList(selector, options) { 12  13     this.list = []; 14  15     // 覆盖默认属性 16     this.options = $.extend({ 17       // 默认属性 18       isDeletable: true, // 设置是否有行删除按钮 19       isEditable: true // 设置是否有行编辑按钮 20     }, options); 21  22     this.element = $(selector) 23       .addClass('panel-group xx-smartlist'); 24  25     console.log('----创建了一个SmartList对象----'); 26   } 27  28   // 更新列表 29   SmartList.prototype.setData = function (list) { 30     var self = this; 31     // 更新list数据 32     this.list = list; 33     // 清空dom容器 34     this.element.html(''); 35     // 渲染元素 36     $.each(this.list, function (i, data) { 37       self._genItem(data).appendTo(self.element); 38     }); 39  40     console.log('-> setData done', this.element); 41   }; 42  43   // 增加一条数据 44   SmartList.prototype.add = function (data) { 45     if(this._getById(data.id)){ 46       console.log('SmartList: id ' + data.id + ' 已存在，无法添加'); 47       return; 48     } 49     this.list.push(data); 50     this._genItem(data).appendTo(this.element);    51   }; 52  53   SmartList.prototype.remove = function (id) { 54     var self = this; 55  56     this._getById(id, function (i, data) { 57       self.list.splice(i, 1); 58       self.element.find('[data-id="' + id + '"]').remove(); 59     }); 60   }; 61  62   SmartList.prototype._getById = function (id, callback) { 63     var self = this; 64     var data = null; 65  66     $.each(this.list, function (i, val) { 67       if (val.id === id) { 68         data = val; 69         if (callback && typeof callback === 'function') 70           callback(i, data); 71         return false; 72       } 73     }); 74  75     return data; 76   }; 77  78   // 生成一个条目 79   SmartList.prototype._genItem = function (data) { 80     var self = this; 81     var heading = 'heading_' + data.id; 82     var collapse = 'collapse_' + data.id; 83     var html = [ 84       '<div class="panel panel-default" data-id="' + data.id + '">', 85       '<div class="panel-heading" role="tab" id="' + heading + '">', 86       '<h4 id="a-role-button-data-toggle-collapse-data-parent-memberList-href-collapse-aria-expanded-true-aria-controls-collapse-data-title-a-this-options-isDeletable-i-data-act-del-class-glyphicon-glyphicon-remove-pull-right-i-this-options-isEditable-i-data-act-edit-class-glyphicon-glyphicon-pencil-pull-right-i">', 87       '<a role="button" data-toggle="collapse" data-parent="#memberList" href="#' + 88       collapse + '" aria-expanded="true" aria-controls="' + collapse + '">', 89       data.title, 90       '</a>', 91       this.options.isDeletable ? '<i data-act="del" class="glyphicon glyphicon-remove pull-right"></i>' : '', 92       this.options.isEditable ? '<i data-act="edit" class="glyphicon glyphicon-pencil pull-right"></i>' : '', 93       '</h4>', 94       '</div>', 95       '<div id="' + collapse + '" class="panel-collapse collapse" role="tabpanel" aria-labelledby="' + heading + '">', 96       '<div class="panel-body">', 97       data.content, 98       '</div>', 99       '</div>',100       '</div>'101     ].join('');102 103     var item = $(html);104 105     if (this.options.isDeletable) {106       item.find('[data-act="del"]').click(function () {107         self.remove(data.id);108       });109     }110 111     return item;112   };113 114   Flexx.SmartList = SmartList;115 116 }(window.xx = window.xx || {});View Code

main.js:

 1 + function () { 2   'use strict'; 3  4   // 创建一个用来测试的模拟数据 5   var members = [{ 6     id: 0, 7     title: 'Brandon', 8     content: 'hello' 9   }, {10     id: 1,11     title: 'Kim',12     content: 'hi'13   }, {14     id: 2,15     title: 'Bunny',16     content: 'hi'17   }, {18     id: 3,19     title: 'Lovelyun',20     content: 'hi'21   }];22 23   var groups = [{24     id: 1,25     title: 'Web Dev',26     content: 'hello again'27   }];28 29   $(function () {30     // 初始化一个SmartList的实例对象31     var memberList = new xx.SmartList('#memberList');32     var groupList = new xx.SmartList('#groupList', {33       isDeletable: false,34       isEditable: false35     });36     // 调用原型方法更新数据37     memberList.setData(members);38     groupList.setData(groups);39 40     $('#btnAdd').click(function () {41       memberList.add({42         id: 4,43         title: 'add',44         content: 'hi'45       });46     });47 48   });49 50 }();View Code

总结：

1、要尽量减少代码重复；

2、充分利用回调函数。

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