AngularJS中ng-repeat渲染完成事件和中间变量的引用

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ng-repeat渲染完成事件

因为在用AngularJS期间, 经常用到ng-repeat, 而有时需要在其渲染完成时操作已经渲染的对象, 所以特在此记录一下添加渲染事件的方法, 以方便以后的使用;

代码如下

myApp.directive('onRepeatFinishedRender', function ($timeout) {  return {    restrict: 'A',    link: function (scope, element, attr) {      if (scope.$last === true) {        $timeout(function () {          //这里element, 就是ng-repeat渲染的最后一个元素          scope.$emit('ngRepeatFinished', element);        });      }    }  };});

这其实是一个指令, 像使用一般指令一样使用就行了, 因为这里设置restrict为"A", 所以只能作为属性插入, 另外, 向回调函数传入element元素, 是为了方便区分多个使用此指令的元素, 比如有两个地方使用, 代码如下

<ul repeat-id="r1">  <li ng-repeat="p in persons track by $index" on-repeat-finished-render>{{p}}</li></ul><ul repeat-id="r2">  <li ng-repeat="a in animates track by $index" on-repeat-finished-render>{{a}}</li></ul><script>  myApp.controller('userCtrl', function ($scope) {    $scope.$on("ngRepeatFinished", function (repeatFinishedEvent, element){      var repeatId = element.parent().attr("repeat-id");      switch (repeatId){        case "r1":          //repeat-id为r1的ul, repeat渲染完成          break;        case "r2":          //repeat-id为r2的ul, repeat渲染完成          break;      }    })  });</script>

中间变量的引用

另外还有一个要用到的, 就是在用filter等的时候, 有时需要用一个中间变量引用filter后的数组, 方便在html中使用, 比如, 我需要在将persons中的数据, 按照'sort'属性排列, 并且需要在repeat元素内需要访问排序后的数组, 可以这么做

<ul>  <li ng-repeat="p in ps=(persons|orderBy:'sort') track by $index" ng-click="upOne(ps, index, $first)">{{p.name}}</li></ul><script>  myApp.controller('userCtrl', function ($scope) {    //这里传过来就是排序后的数组    //此函数的作用就是, 点击元素后, 将当前点击的元素和其上面的元素交换位置    $scope.upOne = function (arr, index, first){      if(!first){        var tmp = arr[index].sort;        arr[index].sort = arr[index-1].sort;        arr[index-1].sort = tmp;      }    }  });</script>

综合实例

下面是一个完整的例子点击下载, 可以通过点击右侧按钮, 进行上移或下移进行排序, 大家可以测试一下

<!DOCTYPE html><html>  <head>    <meta charset="UTF-8">    <script src="http://apps.bdimg.com/libs/angular.js/1.3.9/angular.min.js"></script>    <style>      table{width:600px; margin: auto; border: none; border-padding:0; border-spacing: 0;}      table td{text-align: center;}      table td .button{cursor: pointer; color: #571d00; font-weight: bold;}      table tr{height: 2.5em; vertical-align: middle;}      table tbody tr:nth-child(2n+1){background-color: #f0f0f0;}      table tbody tr:nth-child(2n){background-color: #f0e0ff;}    </style>  </head>  <body ng-app="myApp" ng-controller="userCtrl">    <table>      <thead>        <tr>          <th>索引</th><th>学号</th><th>姓名</th><th>性别</th><th>年龄</th><th>操作</th>        </tr>      </thead>      <tbody repeat-id="r0">        <tr ng-repeat="(si,stu) in students=(persons|orderBy:'sort') track by $index" on-repeat-finished-render>          <td>{{si+1}}</td>          <td>{{stu.id}}</td>          <td>{{stu.name}}</td>          <td>{{stu.gender}}</td>          <td>{{stu.age}}</td>          <td>            <span class="button" ng-click="changeSort(students, si, -1, 'sort')" ng-if="!$first">上移</span>            <span class="split" ng-if="!$first&&!$last"></span>            <span class="button" ng-click="changeSort(students, si, 1, 'sort')" ng-if="!$last">下移</span>          </td>        </tr>      </tbody>    </table>    <script>      var myApp = angular.module('myApp', []);      myApp.directive('onRepeatFinishedRender', function ($timeout) {        return {          restrict: 'A',          link: function (scope, element, attr) {            if (scope.$last === true) {              $timeout(function () {                scope.$emit('ngRepeatFinished', element);              });            }          }        };      });      myApp.controller('userCtrl', function ($scope, $http) {        $scope.persons = [{          id: "161112001",          sort: 0,          name: "赵子龙",          gender: "男",          age: "18"        }, {          id: "161112002",          sort: 2,          name: "吕布",          gender: "男",          age: "18"        }, {          id: "161112003",          sort: 1,          name: "貂蝉",          gender: "女",          age: "18"        }, {          id: "161112004",          sort: 3,          name: "孙尚香",          gender: "女",          age: "18"        }];        $scope.changeSort = function (arr, index, up, attr) {          var temp;          temp = arr[index].sort;          arr[index][attr] = arr[index + up][attr];          arr[index + up][attr] = temp;          return false;        };        $scope.$on("ngRepeatFinished", function (repeatFinishedEvent, element){          console.log(element.parent().attr("repeat-id"));        })      })    </script>  </body></html>

文／jicemoon（简书作者）
原文链接：http://www.jianshu.com/p/4ead962e9dac
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。

源引：http://www.jianshu.com/p/4ead962e9dac

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