深入淺析AngularJS和DataModel

更新時(shí)間：2016年02月16日 17:00:01 作者：Darren Ji

這篇文章主要介紹了深入淺析AngularJS和DataModel 的相關(guān)資料,需要的朋友可以參考下

AngularJS 簡(jiǎn)介

AngularJS 是一個(gè) JavaScript 框架。它可通過 <script> 標(biāo)簽添加到 HTML 頁面。

AngularJS 通過指令擴(kuò)展了 HTML，且通過表達(dá)式綁定數(shù)據(jù)到 HTML。

什么是 AngularJS？

AngularJS 使得開發(fā)現(xiàn)代的單一頁面應(yīng)用程序（SPAs：Single Page Applications）變得更加容易。

AngularJS 把應(yīng)用程序數(shù)據(jù)綁定到 HTML 元素。

AngularJS 可以克隆和重復(fù) HTML 元素。

AngularJS 可以隱藏和顯示 HTML 元素。

AngularJS 可以在 HTML 元素"背后"添加代碼。

AngularJS 支持輸入驗(yàn)證。

通常，在AngularJS中使用JSON作為存儲(chǔ)數(shù)據(jù)的模型。我們可能這樣在controller中寫model：

app.controller('BookController',['$scope',function($scope){
$scope.book = {
id:1,
name:'',
author:'',
stores:[
{id:1, name:'', quantity:2},
{id:2, name:'', quantity:2},
...
]
};
}])

在視圖中也許這樣用到這個(gè)model:

<div ng-controller="BookController">
<span ng-bind="book.id"></span>
<input type="text" ng-model="book.name"/>
<input type="text" ng-model="book.author"/>
</div>

當(dāng)我們需要從服務(wù)端獲取數(shù)據(jù)的時(shí)候，可能這樣寫：

app.controller('BookController',['$scope', '$http', function($scope, $http){
var bookId = 1;
$http.get('api/books'+bookId).success(function(bookData){
$scope.book = bookData;
})
$scope.deleteBook = function(){
$http.delete('api/books/' + bookId);
}
$scope.updateBook = function(){
$http.put('api/books/'+bookId, $scope.book);
}
$scope.getBookImageUrl = function(width, height){
return 'our/iamge/service' +bookId + '/width/height';
}
$scope.isAvailable = function(){
if(!$scope.book.stores || $scope.book.stores.length === 0){
return false;
}
reutrn $scope.book.stores.some(function(store){
return store.quantity > 0;
})
}
}])

在視圖中可能這樣使用：

<div ng-controller="BookController">
<div ng-style="{backgroundImage: 'url('+getBookImageUrl(100,100)+')'}"></div>
<span ng-bind="book.id"></span?
<input type="text" ng-model="book.name"/>
<input type="text" ng-model="book.author"/>
is available: <span ng-bind="isAvailable() ? 'Yes' : 'No'"></span>
<button ng-click="deleteBook()">Delete</button>
<button ng-click="updateBook">Update</button>
</div>

以上，JSON格式的model只能在BookController中使用，如何在其他controller中也可以使用呢？
--通過factory方式

app.factory('Book', ['$http', function($http){
function Book(bookData){
if(bookData){
this.setData(bookData);
}
}
Book.prototype = {
setData: function(bookData){
angular.extend(this, bookData);
},
load: function(id){
var scope = this;
$http.get('api/books/' + bookId).success(function(bookData){
scope.setData(bookData);
})
},
delete: function(bookId){
$http.delete('api/books/' + bookId);
},
update: function(bookId){
$http.put('api/books/' + bookId, this);
},
getImageUrl: function(width, height){
return 'our/image/service/' + this.book.id + '/' + width + '/' + height;
},
isAvailable: funciton(){
if(!this.book.stores || this.book.stores.length === 0) {
return false;
} 
return this.book.stores.some(function(store){
return store.quantity > 0;
})
}
}
return Book;
}])

以上，通過factory的方式創(chuàng)建了類似Book的一個(gè)Data Model，現(xiàn)在可以注入到controller中去了。

app.controller('BookController', ['$scope', 'Book', function($scope, Book){
$scope.book = new Book();
$scope.book.load(1);
}])

在視圖中也會(huì)有相應(yīng)的變化。

<div ng-controller="BookController">
<div ng-style="{backgroundImage: 'url(' + book.getImageUrl(100, 100) + ')'}"></div>
<span ng-bind="book.id"></span>
<input type="text" ng-model="book.name"/>
<input type="text" ng-model="book.author"/>
is abailble: <span ng-bind="book.isAvailabe() ? 'Yes' : 'No'"></span>
<button ng-click="book.delete()">Delete</button>
<button ng-click="book.update()">Update</button>
</div>

以上，多個(gè)controller可以使用同一個(gè)有關(guān)book的Data Model了，如果多個(gè)controller處理同一個(gè)有關(guān)book的Data Model呢？

app.factory('booksManager', ['$http', '$q', 'Book', function($http. $q, Book){
var booksManager = {
_pool: {},
_retrieveInstance: function(bookId, bookData){
var instance = this._pool[bookId];
if(instance){
instance.setData(bookData);
} else {
instance = new Book(bookData);
this._pool[bookId] = instance;
}
return instance;
},
_seach: function(bookId){
reutrn this_.pool[bookId];
},
_load: function(bookId, deferred){
var scope = this;
$http.get('api/books/' + bookId)
.success(funciton(bookData){
var book = scope._retrieveInstance(bookData.id, bookData);
deferred.resolve(book);
})
.error(function(){
deferred.reject();
})
},
getBook: function(bookId){
var deferred = $q.defer();
var book = this._search(bookId);
if(book){
deferred.resove(book);
} else {
this._load(bookId, deferred);
}
return deferred.promise;
},
loadAllBooks: function(){
var deferred = $q.defer();
var scope = this;
$http.get('api/books')
.success(function(booksArray){
var books = [];
booksArray.forEach(function(bookData){
var book = scope.l_retrieveInstance(bookData.id, bookData);
books.push(book);
});
deferred.resolve(books);
})
.error(function(){
deferred.reject();
});
return deferred.promise;
}，
setBook: function(bookData){
var scope = this;
var book = this._search(bookData.id);
if(book){
book.setData(bookData);
} else {
book = scope._retrieveInstance(bookData);
}
return book;
}
};
return booksManager;
}])

Book服務(wù)去掉load方法。

app.factory('Book', ['$http', function($http) { 
function Book(bookData) {
if (bookData) {
this.setData(bookData):
}
// Some other initializations related to book
};
Book.prototype = {
setData: function(bookData) {
angular.extend(this, bookData);
},
delete: function() {
$http.delete('ourserver/books/' + bookId);
},
update: function() {
$http.put('ourserver/books/' + bookId, this);
},
getImageUrl: function(width, height) {
return 'our/image/service/' + this.book.id + '/width/height';
},
isAvailable: function() {
if (!this.book.stores || this.book.stores.length === 0) {
return false;
}
return this.book.stores.some(function(store) {
return store.quantity > 0;
});
}
};
return Book;
}]);

現(xiàn)在，多個(gè)controller可以使用同一個(gè)booksManager服務(wù)。

app.controller('EditableBookController',['$scope', 'booksManager', function($scope, booksManager){
booksManager.getBook(1).then(function(book){
$scope.book = book;
})
}])
.controller('BooksListController',['$scope', 'booksManager', function($scope, booksManager){
booksManager.loadAllBooks().then(function(books){
$scope.books = books;
})
}])

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