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