Eine eingehende Analyse von AngularJS und DataModel_AngularJS

Einführung in AngularJS

AngularJS ist ein JavaScript-Framework. Es kann über das Tag 3f1c4e4b6b16bbbd69b2ee476dc4f83a zu HTML-Seiten hinzugefügt werden.

AngularJS erweitert HTML durch Anweisungen und bindet Daten durch Ausdrücke an HTML.

Was ist AngularJS?

AngularJS erleichtert die Entwicklung moderner Single-Page-Anwendungen (SPAs: Single Page Applications).

AngularJS bindet Anwendungsdaten an HTML-Elemente.

AngularJS kann HTML-Elemente klonen und wiederholen.

AngularJS kann HTML-Elemente ein- und ausblenden.

AngularJS kann Code „hinter“ HTML-Elementen hinzufügen.

AngularJS unterstützt die Eingabevalidierung.

Normalerweise wird JSON als Modell zum Speichern von Daten in AngularJS verwendet. Wir können das Modell wie folgt in den Controller schreiben:

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

Vielleicht verwenden Sie dieses Modell in der Ansicht wie folgt:

<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> 

Wenn wir Daten vom Server benötigen, können wir so schreiben:

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;
})
}
}]) 

kann in einer Ansicht wie folgt verwendet werden:

<div ng-controller="BookController">
<div ng-style="{backgroundImage: 'url('+getBookImageUrl(100,100)+')'}"></div>
<span ng-bind="book.id"></span&#63;
<input type="text" ng-model="book.name"/>
<input type="text" ng-model="book.author"/>
is available: <span ng-bind="isAvailable() &#63; 'Yes' : 'No'"></span>
<button ng-click="deleteBook()">Delete</button>
<button ng-click="updateBook">Update</button>
</div> 

Oben kann das Modell im JSON-Format nur in BookController verwendet werden. Wie kann es in anderen Controllern verwendet werden?
--Nach der Fabrikmethode

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;
}]) 

Oben wurde über die Fabrik ein Datenmodell ähnlich dem von Book erstellt, das nun in den Controller eingefügt werden kann.

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

Auch in der Ansicht wird es entsprechende Änderungen geben.

<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() &#63; 'Yes' : 'No'"></span>
<button ng-click="book.delete()">Delete</button>
<button ng-click="book.update()">Update</button>
</div> 

Wie oben können mehrere Controller dasselbe Datenmodell für Bücher verwenden. Was passiert, wenn mehrere Controller dasselbe Datenmodell für Bücher verarbeiten?

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;
}]) 

Der Buchservice entfernt die Lademethode.

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;
}]); 

Jetzt können mehrere Controller denselben BooksManager-Dienst verwenden.

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;
})
}])