深究angularJS系列 - 第二弹
深究angularJS系列 - 第二弹,在初步了解了Angular的基础上,进一步的针对Angular的控制器和作用域问题深入探究O(∩_∩)O~~
Angular控制器
控制器(Controller)的理解
- 控制器是对view的抽象,用来接收view的事件,响应view的请求;
- 控制器包含view的静态属性和动态的方法;
- 控制器与view是一对一的关系。
控制器(Controller)的结构
1 .controller("控制器的名字",function($scoppe){ 2 ...... 3 })
说明:
1.控制器的命名:
业务名(view模块名)+Controller 见名之意,以登录(login)为例
1 .controller("loginController",function(类1,类2,...){ 2 ...... 3 })
2.Angular中的$:
$:Angular内部类的标识,可借此区分一个类是angular的内部类,还是自定的类 如:
1 $scope 2 $rootScope
3.Angular中类的声明:
Angular里面不能直接的类进行实例化调用,只能先声明后使用 如:
1 .controller("oneCtrl",function($scope){ //类先声明 2 $scope.msg = "helle controller!"; 3 }) 4 5 .controller("twoCtrl",function(){ //类没声明,会报错 6 var s = new $scope(); //直接的类进行实例化 7 s.msg = "helle controller!"; 8 })
4.Angular中控制器与view是一对一的:
1 <body> 2 <div ng-controller="one">{{goods}}</div> 3 <div ng-controller="two">{{goods}}</div> 4 <script> 5 (function(){ 6 var son = angular.module("one",[]); 7 son.controller("oneCtrl",function($scope){ 8 $scope.goods="one goods" 9 }); 10 var grandson = angular.module("two",[]); 11 grandson.controller("twoCtrl",function($scope){ 12 $scope.goods="two goods" 13 }); 14 })() 15 </script>
5.Angular中控制器的继承关系:
当Controller之间出现嵌套关系的时候,内层继承外层的变量 如:
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>控制器之间的继承</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body> 10 <div class="well" ng-controller="oneCtrl"> 11 {{msg}} 12 <div class="well" ng-controller="twoCtrl"> 13 {{msg}} 14 <div class="well" ng-controller="threeCtrl"> 15 {{msg}} 16 </div> 17 </div> 18 </div> 19 <script src="../angular.js"></script> 20 <script> 21 (function(){ 22 angular.module("demo",[]) 23 //当我们的html元素出现嵌套关系的时候,内层继承外层的变量 24 .controller("oneCtrl",function($scope){ 25 $scope.msg = "helle one!" 26 27 }) 28 .controller("twoCtrl",function($scope){ 29 // $scope.msg = "helle two!" 30 }) 31 .controller("threeCtrl",function($scope){ 32 // $scope.msg = "helle three!" 33 }) 34 })() 35 </script> 36 </body> 37 </html>
结果如下:
6.Angular中的注入器($injector)两种注入方式:
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body> 10 <div ng-controller="one">{{msg}}</div> 11 <div ng-controller="two">{{msg}}</div> 12 <script src="../angular.js"></script> 13 <script> 14 (function(){ 15 angular.module("demo",[]) 16 //第一种直接声明注入(有缺陷,在gulp,webpack打包时,会把function(a)的参数压缩掉,导致声明失败) 17 .controller("one",function($scope,$rootScope){ 18 //$injector 19 $scope.msg = "hi"; 20 }) 21 //第二种经常采用以下写法 22 .controller("two",["$scope","$rootScope",function($s,$rs){ 23 $s.msg = "hello"; 24 }]) 25 })() 26 </script> 27 </body> 28 </html>
7.Angular中的run()方法:
run是Angular中的main方法,是 Angular 的入口方法
特点:run只会在angular生命周期内,只会调用一次
用于Angular中的条件判断,比如登录时的用户名和密码,只会调用一次存入localstorage,判断是否允许登录
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body> 10 <script src="../angular.js"></script> 11 <script> 12 (function(){ 13 angular.module("demo",[]) 14 //整个程序级别 15 .run(function(){ 16 console.log("hello run"); 17 //条件的判断 localstorage 18 window.localStorage.setItem("ng","haha"); 19 }) 20 })() 21 </script> 22 </body> 23 </html>
Angular作用域
$rootScope类:
- $rootScope是一个angular的内部类
- $rootScope是用于根的模块的数据缓存
- $rootScope用于解决Controller之间的数据共享问题
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>$rootScope</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body> 10 <div class="well" ng-controller="oneCtrl"> 11 {{msg}} {{txt}} 12 <div class="well" ng-controller="twoCtrl"> 13 {{msg}}{{txt}} 14 <div class="well" ng-controller="threeCtrl"> 15 {{msg}}{{txt}} 16 </div> 17 </div> 18 </div> 19 <script src="../angular.js"></script> 20 <script> 21 (function(){ 22 angular.module("demo",[]) 23 .controller("oneCtrl",function($scope,$rootScope){ 24 $scope.msg = "helle one!"; 25 26 }) 27 .controller("twoCtrl",function($scope){ 28 // $scope.msg = "helle two!" 29 }) 30 .controller("threeCtrl",function($scope,$rootScope){ 31 // $scope.msg = "helle three!" 32 $rootScope.txt = "hello root"; 33 }) 34 })() 35 </script> 36 </body> 37 </html>
效果如下:
$scope类
- $scope是用于绑定view的抽象(属性和方法)
- $scope是连接controller与view之间的数据桥梁
- $scope是实现angular中的mvvm模块的核心类
- $scope是实现双向数据绑定的关键类
- $scope是用来监视view,Model值之间的数据变化,并通知对方,从而实现view与model之间的数据同步
- $scope可以实现controller与controller之间的事件传递 js事件冒泡 事件捕获
1.作用域
如案例:$rootScope,$scope,var msg2 = "hello2"的不同作用域
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body > 10 <div ng-controller="one"> 11 {{msg}} 12 {{msg2}} 13 {{txt}} 14 </div> 15 <div ng-controller="tow"> 16 {{msg}} 17 {{txt}} 18 </div> 19 <script src="../angular.js"></script> 20 <script> 21 (function(){ 22 angular.module("demo",[]) 23 .controller("one",function($scope,$rootScope){ 24 $scope.msg = "hello"; 25 var msg2 = "hello2"; 26 $rootScope.txt = "hello3" 27 }) 28 .controller("tow",function($scope){ 29 30 }) 31 })() 32 </script> 33 </body> 34 </html>
效果如下:
2.$scope事件数据传递
- $scope.$emit是向上一级控制器发送事件 冒泡
- $scope.$broadcast 向下传递事件 捕获
- $scope.$on用来接收事件的值
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body> 10 <div class="well" ng-controller="one"> 11 {{msg}} 12 <div class="well" ng-controller="two"> 13 14 <a class="btn btn-danger" ng-click="sendEvent()">sendEvent</a> 15 <div class="well" ng-controller="three"> 16 {{msg}} 17 </div> 18 </div> 19 </div> 20 <script src="../angular.js"></script> 21 <script> 22 (function(){ 23 angular.module("demo",[]) 24 .controller("one",["$scope",function(s){ 25 s.$on("sendOne",function(event,data){ 26 s.msg = data; 27 }); 28 }]) 29 .controller("two",["$scope",function(s){ 30 s.sendEvent = function(){ 31 s.$emit("sendOne","a gift from two "); 32 s.$broadcast("sendThree","a command from two"); 33 } 34 }]) 35 .controller("three",["$scope",function(s){ 36 s.$on("sendThree",function(event,data){ 37 s.msg = data; 38 }); 39 }]) 40 })() 41 </script> 42 </body> 43 </html>
效果如下:
3.AngularJS在什么情况下才执行双向绑定?
- 手动触发dirty checking -> $scope.$appply()
- 主动触发(ng-指令绑定值 $服务类)/被动
dirty checking 绑定的值与上一次缓存中的值有没有变化,如果有变化,数据dirty,怎么才能知道绑定的值发生了变化呢?
当我们在$scope上面绑定一个属性的时候,angular就会在这个属性上添加一个$$watcher(): 多长时间后缓存一次数据。
$watcher会执行值的比较。当这次比较的值不相等的时候,表示watcher的值,需要进行数据同步
data $digest $watherlist date ->$wathe()->把model-view之间的数据进行更新同步
1 <!DOCTYPE html> 2 <html lang="en" ng-app="demo"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"> 7 <link rel="stylesheet" href="../bootstrap.css"> 8 </head> 9 <body ng-controller="one"> 10 <input type="text" ng-model="txt"> {{txt}} 11 {{date}} 12 <script src="../angular.js"></script> 13 <script> 14 (function(){ 15 angular.module("demo",[]) 16 .controller("one",function($scope,$interval){ 17 $scope.date = new Date().toLocaleTimeString() 18 //$interval(触发dirtychecking) == setInterval 19 $interval(function(){ 20 $scope.date = new Date().toLocaleTimeString() 21 },1000); 22 }) 23 })() 24 </script> 25 </body> 26 </html>
效果如下:
敬请留言指正补充交流!
(未完待续~~)