angular学习笔记(三十)-指令(10)-require和controller

本篇介绍指令的最后两个属性,require和controller

当一个指令需要和父元素指令进行通信的时候,它们就会用到这两个属性,什么意思还是要看栗子:

html:

<outer‐directive>
    <inner‐directive></inner‐directive>
</outer‐directive> 

这里有两个指令,一个outer-directive指令元素,它里面又有一个inner-directive指令元素.

js:

app.directive('outerDirective',function(){
    return {
        scope: {},
        restrict: 'AE',
        controller: function($scope,$compile,$http){
            this.addChild = function(nestedDirective){ //this指代controller
            console.log('Got the message from nested directive' + nestedDirective.message);
            }
        }
    }
});    

app.directive('innerDirective',function(){
    return {
        scope: {},
        restrict: 'AE',
        require: '^?outerDirective',
        link: function(scope,elem,attrs,ctrl){
            //第四个参数是你require的controller实例
            scope.message = 'Hi, Parent directive';
            ctrl.addChild(scope);
        }
    };
});  

在父元素指令里定义controller方法:

function($scope,$compile,$http){
   this.addChild = function(nestedDirective){ //this指代controller
       console.log('Got the message from nested directive' + nestedDirective.message);
   }
}

controller方法是一个构造函数,可以给它添加对象的方法(什么是对象的方法看这里:mvc-javascript-web-application / 01.MVC和类 / 1.创建类库 / ex1.3(对象的方法).html).

在子元素指令里定义require属性:require: '^?outerDirective',表示向外层寻找outerDirective指令,直到找到为止.注意:向外层寻找,也包括了自己本身,也就是说,自己可以寻找到自己身上的其它指令.

'?'的作用是如果找不到也不会报错.

定义了require属性后,link函数的第四个参数ctrl就是require到的指令的controller方法的实例.所以ctrl就有了addChild方法了.

下面看一个难一点的栗子:

angular学习笔记(三十)-指令(9)-一个简单的指令示例这个栗子是单个子菜单的展开收起,下面使用require和controller,来扩展这个应用,改成多个菜单,要求点击某个菜单的时候展开此菜单,而其余菜单都收起:

如下过程:

html:

<!DOCTYPE html>
<html ng-app="accordionModule">
<head>
  <title>20.10 指令-accordion</title>
  <meta charset="utf-8">
  <link href="../bootstrap.css" rel="stylesheet">
  <script src="../angular.min.js"></script>
  <script type="text/ng-template" id="vertical.html">
    <div class="btn-group-vertical" ng-transclude>
    </div>
  </script>
  <script type="text/ng-template" id="text.html">
    <div class="btn-group">
      <button class="btn btn-default dropdown-toggle" type="button" ng-click="toggle()">{{title}}<span class="caret"></span></button>
      <ul class="dropdown-menu" ng-show="ifShow" ng-transclude></ul>
    </div>
  </script>
  <script src="script.js"></script>
  <style type="text/css">
    body{
      padding:40px
    }
  </style>
</head>
<body>
  <div ng-controller="accordionCtrl">
    <accordion>
      <expander ng-repeat="list in lists" my-title="{{list.title}}">
        <li ng-repeat="content in list.contents">
          <a href="">{{content}}</a>
        </li>
      </expander>
    </accordion>
  </div>
</body>
</html>

js:

/*20.10 指令*/
var accordionModule = angular.module('accordionModule',[]);
accordionModule.controller('accordionCtrl',function($scope){
    $scope.lists = [
        {title:'标题1',contents:['bunny1','cat1','dog1']},
        {title:'标题2',contents:['bunny2','cat2','dog2']},
        {title:'标题3',contents:['bunny3','cat3','dog3']},
        {title:'标题4',contents:['bunny4','cat4','dog4']},
        {title:'标题5',contents:['bunny5','cat5','dog5']},
        {title:'标题6',contents:['bunny6','cat6','dog6']},
        {title:'标题7',contents:['bunny7','cat7','dog7']},
        {title:'标题8',contents:['bunny8','cat8','dog8']}
    ]
});
accordionModule.directive('accordion',function(){
    return {
        restrict:'EA',
        replace:true,
        templateUrl:'vertical.html',
        transclude:true,
        controller:function(){
            this.expanders = [];
            this.closeAll = function(scope){
                angular.forEach(this.expanders,function(expander){
                    if(scope!=expander)
                    expander.ifShow = false;
                })
            };
            this.addExpander = function(scope){
                this.expanders.push(scope)
            }
        }
    }
});
accordionModule.directive('expander',function(){
    return {
        restrict:'EA',
        replace:true,
        templateUrl:'text.html',
        transclude:true,
        scope:{title:'@myTitle'},
        require:'^?accordion',
        link:function(scope,ele,attrs,ctrl){
            scope.ifShow = false;
            ctrl.addExpander(scope);
            scope.toggle = function(){
                ctrl.closeAll(scope);
                scope.ifShow = !scope.ifShow;
            }
        }
    }
});

下面来解释这个应用:

1. accordion指令的controller的实例也就是link函数的第四个参数ctrl

2. 将expander指令进行ng-repeat,渲染出多个子菜单.

3. 由于这些子菜单是互相有关联而非独立存在的,所以将他们放在一个accordion指令中.

4. 绑定数据模型都和单独的expander一样,唯一不同的是:

1) link函数中调用ctrl的addExpander方法,将每个expander的独立scope压入ctrl的expanders数组中.

2) toggle()方法,它调用了accordion指令的controller的实例的方法.收起除了当前点击项以外其余的菜单.

5. 注意ctrl是唯一的ctrl,而不是每次都实例化出一个新的实例.虽然有多个expander,但是它的ctrl指向的是同一个实例,所以expanders数组是唯一的.

6. 这里expanders数组里存放是每个expander的scope,为什么是scope而不是element呢? 因为closeAll方法需要修改指令独立作用域下的ifShow的,所以这里数组里存放scope比较好写.

完整代码: https://github.com/OOP-Code-Bunny/angular/blob/master/OREILLY/20.10%20%E6%8C%87%E4%BB%A4.html

https://github.com/OOP-Code-Bunny/angular/blob/master/OREILLY/script.js