chrome/common/extensions/docs/templates/articles/app_codelab3_mvc.html

   1 <h1 id="lab_3_model_view_controller">Create MVC</h1>
   2
   3 <p>Whenever your application grows beyond a single script with a few dozen lines,
   4 it gets harder and harder to manage without a good separation
   5 of roles among app components.
   6 One of the most common models for structuring a complex application,
   7 no matter what language,
   8 is the Model-View-Controller (MVC) and its variants,
   9 like Model-View-Presentation (MVP).</p>
  10
  11 <p>There are several frameworks to help apply
  12 <a href="app_frameworks.html">MVC concepts</a>
  13 to a Javascript application, and most of them,
  14 as long as they are CSP compliant, can be used in a Chrome App.
  15 In this lab,
  16 we'll add an MVC model using both pure JavaScript and
  17 the <a href="http://angularjs.org/">AngularJS</a> framework.
  18 Most of the AngularJS code from this section was copied,
  19 with small changes, from the AngularJS Todo tutorial.</p>
  20
  21 <p class="note"><b>Note:</b>
  22 Chrome Apps don&#39;t enforce any specific framework or programming style.
  23 </p>
  24
  25 <h2 id="simple">Create a simple view</h2>
  26
  27 <h3 id="basic-mvc">Add MVC basics</h3>
  28
  29 <p>If using AngularJS, download the
  30 <a href="http://ajax.googleapis.com/ajax/libs/angularjs/1.0.2/angular.min.js">Angular script</a>
  31 and save it as
  32 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/angularjs/simpleview/angular.min.js">angular.min.js</a>.</p>
  33
  34 <p>If using JavaScript,
  35 you will need to add a very simple controller with basic MVC functionalities:
  36 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/javascript/simpleview/controller.js">JavaScript controller.js</a></p>
  37
  38 <h3 id="update-view">Update view</h3>
  39
  40 <p>Change the <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/angularjs/simpleview/index.html">AngularJS index.html</a> or
  41 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/javascript/simpleview/index.html">JavaScript index.html</a> to use a simple sample:
  42 </p>
  43
  44 <tabs data-group="source">
  45
  46   <header tabindex="0" data-value="angular">Angular</header>
  47   <header tabindex="0" data-value="js">JavaScript</header>
  48
  49   <content>
  50     <pre data-filename="index.html">
  51 &lt;!doctype html&gt;
  52 &lt;html ng-app ng-csp&gt;
  53   &lt;head&gt;
  54     &lt;script src=&quot;angular.min.js&quot;&gt;&lt;/script&gt;
  55     &lt;link rel="stylesheet" href="todo.css"&gt;
  56   &lt;/head&gt;
  57   &lt;body&gt;
  58     &lt;h2&gt;Todo&lt;/h2&gt;
  59     &lt;div&gt;
  60       &lt;ul&gt;
  61         &lt;li&gt;
  62           &#123;&#123;todoText&#125;&#125;
  63         &lt;/li&gt;
  64       &lt;/ul&gt;
  65       &lt;input type=&quot;text&quot; ng-model=&quot;todoText&quot;  size="30"
  66              placeholder=&quot;type your todo here&quot;&gt;
  67     &lt;/div&gt;
  68   &lt;/body&gt;
  69 &lt;/html&gt;
  70     </pre>
  71   </content>
  72   <content>
  73     <pre data-filename="index.html">
  74 &lt;!doctype html&gt;
  75 &lt;html&gt;
  76   &lt;head&gt;
  77     &lt;link rel=&quot;stylesheet&quot; href=&quot;todo.css&quot;&gt;
  78   &lt;/head&gt;
  79   &lt;body&gt;
  80     &lt;h2&gt;Todo&lt;/h2&gt;
  81     &lt;div&gt;
  82       &lt;ul&gt;
  83         &lt;li id=&quot;todoText&quot;&gt;
  84         &lt;/li&gt;
  85       &lt;/ul&gt;
  86       &lt;input type=&quot;text&quot; id=&quot;newTodo&quot; size=&quot;30&quot;
  87              placeholder=&quot;type your todo here&quot;&gt;
  88     &lt;/div&gt;
  89     &lt;script src=&quot;controller.js&quot;&gt;&lt;/script&gt;
  90   &lt;/body&gt;
  91 &lt;/html&gt;
  92     </pre>
  93   </content>
  94 </tabs>
  95
  96 <p class="note"><b>Note:</b>  The <code>ng-csp</code> directive tells Angular to run in a &quot;content security mode&quot;. You don&#39;t need this directive when using Angular v1.1.0+. We&#39;ve included it here so that the sample works regardless of the Angular version in use.</p>
  97
  98 <h3 id="stylesheet">Add stylesheet</h3>
  99
 100 <p><a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/angularjs/simpleview/todo.css">AngularJS todo.css</a> and
 101 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/javascript/simpleview/todo.css">JavaScript todo.css</a> are the same:
 102 </p>
 103
 104 <pre data-filename="todo.css">
 105 body {
 106   font-family: "Helvetica Neue",Helvetica,Arial,sans-serif;
 107 }
 108
 109 ul {
 110   list-style: none;
 111 }
 112
 113 button, input[type=submit] {
 114   background-color: #0074CC;
 115   background-image: linear-gradient(top, #08C, #05C);
 116   border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
 117   text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
 118   color: white;
 119 }
 120
 121 .done-true {
 122   text-decoration: line-through;
 123   color: grey;
 124 }
 125 </pre>
 126
 127 <h3 id="check1">Check the results</h3>
 128
 129 <p>
 130 Check the results by reloading the app: open the app, right-click and select Reload App.</li>
 131 </p>
 132
 133 <h2 id="real-todo">Create real Todo list</h2>
 134
 135 <p>
 136 The previous sample, although interesting, is not exactly useful.
 137 Let&#39;s transform it into a real Todo list, instead of a simple Todo item.
 138 </p>
 139
 140 <h3 id="controller">Add controller</h3>
 141
 142 <p>
 143 Whether using pure JavaScript or AngularJS,
 144 the controller manages the Todo list:
 145 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/angularjs/withcontroller/controller.js">AngularJS controller.js</a> or
 146 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/javascript/withcontroller/controller.js">JavaScript controller.js</a>.
 147 </p>
 148
 149 <tabs data-group="source">
 150
 151   <header tabindex="0" data-value="angular">Angular</header>
 152   <header tabindex="0" data-value="js">JavaScript</header>
 153
 154   <content>
 155     <pre data-filename="controller.js">
 156 function TodoCtrl($scope) {
 157   $scope.todos = [
 158     {text:&#39;learn angular&#39;, done:true},
 159     {text:&#39;build an angular Chrome packaged app&#39;, done:false}];
 160
 161 $scope.addTodo = function() {
 162     $scope.todos.push({text:$scope.todoText, done:false});
 163     $scope.todoText = &#39;&#39;;
 164   };
 165
 166 $scope.remaining = function() {
 167     var count = 0;
 168     angular.forEach($scope.todos, function(todo) {
 169       count += todo.done ? 0 : 1;
 170     });
 171     return count;
 172   };
 173
 174 $scope.archive = function() {
 175     var oldTodos = $scope.todos;
 176     $scope.todos = [];
 177     angular.forEach(oldTodos, function(todo) {
 178       if (!todo.done) $scope.todos.push(todo);
 179     });
 180   };
 181 }
 182     </pre>
 183   </content>
 184   <content>
 185     <pre data-filename="controller.js">
 186 (function(exports) {
 187
 188   var nextId = 1;
 189
 190   var TodoModel = function() {
 191     this.todos = {};
 192     this.listeners = [];
 193   }
 194
 195   TodoModel.prototype.clearTodos = function() {
 196     this.todos = {};
 197     this.notifyListeners('removed');
 198   }
 199
 200   TodoModel.prototype.archiveDone = function() {
 201     var oldTodos = this.todos;
 202     this.todos={};
 203     for (var id in oldTodos) {
 204       if ( ! oldTodos[id].isDone ) {
 205         this.todos[id] = oldTodos[id];
 206       }
 207     }
 208     this.notifyListeners('archived');
 209   }
 210
 211   TodoModel.prototype.setTodoState = function(id, isDone) {
 212     if ( this.todos[id].isDone != isDone ) {
 213       this.todos[id].isDone = isDone;
 214       this.notifyListeners('stateChanged', id);
 215     }
 216   }
 217
 218   TodoModel.prototype.addTodo = function(text, isDone) {
 219     var id = nextId++;
 220     this.todos[id]={'id': id, 'text': text, 'isDone': isDone};
 221     this.notifyListeners('added', id);
 222   }
 223
 224   TodoModel.prototype.addListener = function(listener) {
 225     this.listeners.push(listener);
 226   }
 227
 228   TodoModel.prototype.notifyListeners = function(change, param) {
 229     var this_ = this;
 230     this.listeners.forEach(function(listener) {
 231       listener(this_, change, param);
 232     });
 233   }
 234
 235   exports.TodoModel = TodoModel;
 236
 237 })(window);
 238
 239
 240 window.addEventListener('DOMContentLoaded', function() {
 241
 242   var model = new TodoModel();
 243   var form = document.querySelector('form');
 244   var archive = document.getElementById('archive');
 245   var list = document.getElementById('list');
 246   var todoTemplate = document.querySelector('#templates &gt; [data-name="list"]');
 247
 248   form.addEventListener('submit', function(e) {
 249     var textEl = e.target.querySelector('input[type="text"]');
 250     model.addTodo(textEl.value, false);
 251     textEl.value=null;
 252     e.preventDefault();
 253   });
 254
 255   archive.addEventListener('click', function(e) {
 256     model.archiveDone();
 257     e.preventDefault();
 258   });
 259
 260   model.addListener(function(model, changeType, param) {
 261     if ( changeType === 'removed' || changeType === 'archived') {
 262       redrawUI(model);
 263     } else if ( changeType === 'added' ) {
 264       drawTodo(model.todos[param], list);
 265     } else if ( changeType === 'stateChanged') {
 266       updateTodo(model.todos[param]);
 267     }
 268     updateCounters(model);
 269   });
 270
 271   var redrawUI = function(model) {
 272     list.innerHTML='';
 273     for (var id in model.todos) {
 274       drawTodo(model.todos[id], list);
 275     }
 276   };
 277
 278   var drawTodo = function(todoObj, container) {
 279     var el = todoTemplate.cloneNode(true);
 280     el.setAttribute('data-id', todoObj.id);
 281     container.appendChild(el);
 282     updateTodo(todoObj);
 283     var checkbox = el.querySelector('input[type="checkbox"]');
 284     checkbox.addEventListener('change', function(e) {
 285       model.setTodoState(todoObj.id, e.target.checked);
 286     });
 287   }
 288
 289   var updateTodo = function(model) {
 290     var todoElement = list.querySelector('li[data-id="'+model.id+'"]');
 291     if (todoElement) {
 292       var checkbox = todoElement.querySelector('input[type="checkbox"]');
 293       var desc = todoElement.querySelector('span');
 294       checkbox.checked = model.isDone;
 295       desc.innerText = model.text;
 296       desc.className = "done-"+model.isDone;
 297     }
 298   }
 299
 300   var updateCounters = function(model) {
 301     var count = 0;
 302     var notDone = 0;
 303     for (var id in model.todos) {
 304       count++;
 305       if ( ! model.todos[id].isDone ) {
 306         notDone ++;
 307       }
 308     }
 309     document.getElementById('remaining').innerText = notDone;
 310     document.getElementById('length').innerText = count;
 311   }
 312
 313   updateCounters(model);
 314
 315 });
 316     </pre>
 317   </content>
 318 </tabs>
 319
 320 <h3 id="index">Update view</h3>
 321
 322 <p>Change the <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/angularjs/withcontroller/index.html">AngularJS index.html</a> or
 323 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab3_mvc/javascript/withcontroller/index.html">JavaScript index.html</a>:
 324 </p>
 325
 326 <tabs data-group="source">
 327
 328   <header tabindex="0" data-value="angular">Angular</header>
 329   <header tabindex="0" data-value="js">JavaScript</header>
 330
 331   <content>
 332     <pre data-filename="index.html">
 333 &lt;html ng-app ng-csp&gt;
 334   &lt;head&gt;
 335     &lt;script src=&quot;angular.min.js&quot;&gt;&lt;/script&gt;
 336     &lt;script src=&quot;controller.js&quot;&gt;&lt;/script&gt;
 337     &lt;link rel=&quot;stylesheet&quot; href=&quot;todo.css&quot;&gt;
 338   &lt;/head&gt;
 339   &lt;body&gt;
 340     &lt;h2&gt;Todo&lt;/h2&gt;
 341     &lt;div ng-controller=&quot;TodoCtrl&quot;&gt;
 342       &lt;span&gt;&#123;&#123;remaining()&#125;&#125; of &#123;&#123;todos.length&#125;&#125; remaining&lt;/span&gt;
 343       [ &lt;a href=&quot;&quot; ng-click=&quot;archive()&quot;&gt;archive&lt;/a&gt; ]
 344       &lt;ul&gt;
 345         &lt;li ng-repeat=&quot;todo in todos&quot;&gt;
 346           &lt;input type=&quot;checkbox&quot; ng-model=&quot;todo.done&quot;&gt;
 347           &lt;span class=&quot;done-&#123;&#123;todo.done&#125;&#125;&quot;&gt;&#123;&#123;todo.text&#125;&#125;&lt;/span&gt;
 348         &lt;/li&gt;
 349       &lt;/ul&gt;
 350       &lt;form ng-submit=&quot;addTodo()&quot;&gt;
 351         &lt;input type=&quot;text&quot; ng-model=&quot;todoText&quot; size=&quot;30&quot;
 352                placeholder=&quot;add new todo here&quot;&gt;
 353         &lt;input class=&quot;btn-primary&quot; type=&quot;submit&quot; value=&quot;add&quot;&gt;
 354       &lt;/form&gt;
 355     &lt;/div&gt;
 356   &lt;/body&gt;
 357 &lt;/html&gt;
 358     </pre>
 359   </content>
 360   <content>
 361     <pre data-filename="index.html">
 362 &lt;!doctype html&gt;
 363 &lt;html&gt;
 364   &lt;head&gt;
 365     &lt;link rel=&quot;stylesheet&quot; href=&quot;todo.css&quot;&gt;
 366   &lt;/head&gt;
 367   &lt;body&gt;
 368     &lt;h2&gt;Todo&lt;/h2&gt;
 369     &lt;div&gt;
 370       &lt;span&gt;&lt;span id=&quot;remaining&quot;&gt;&lt;/span&gt; of &lt;span id=&quot;length&quot;&gt;&lt;/span&gt; remaining&lt;/span&gt;
 371       [ &lt;a href=&quot;&quot; id=&quot;archive&quot;&gt;archive&lt;/a&gt; ]
 372       &lt;ul class=&quot;unstyled&quot; id=&quot;list&quot;&gt;
 373       &lt;/ul&gt;
 374       &lt;form&gt;
 375         &lt;input type=&quot;text&quot; size=&quot;30&quot;
 376                placeholder=&quot;add new todo here&quot;&gt;
 377         &lt;input class=&quot;btn-primary&quot; type=&quot;submit&quot; value=&quot;add&quot;&gt;
 378       &lt;/form&gt;
 379     &lt;/div&gt;
 380
 381     &lt;!-- poor man's template --&gt;
 382     &lt;div id=&quot;templates&quot; style=&quot;display: none;&quot;&gt;
 383       &lt;li data-name=&quot;list&quot;&gt;
 384         &lt;input type=&quot;checkbox&quot;&gt;
 385         &lt;span&gt;&lt;/span&gt;
 386       &lt;/li&gt;
 387     &lt;/div&gt;
 388
 389     &lt;script src=&quot;controller.js&quot;&gt;&lt;/script&gt;
 390   &lt;/body&gt;
 391 &lt;/html&gt;
 392     </pre>
 393   </content>
 394 </tabs>
 395
 396 <p>Note how the data, stored in an array inside the controller, binds to the view and is automatically updated when it is changed by the controller.</p>
 397
 398 <h3 id="check2">Check the results</h3>
 399
 400 <p>
 401 Check the results by reloading the app: open the app, right-click and select Reload App.</li>
 402 </p>
 403
 404 <h2 id="takeaways_">Takeaways</h2>
 405
 406 <ul>
 407 <li><p>Chrome Apps are
 408 <a href="offline_apps.html">offline first</a>,
 409 so the recommended way to include third-party scripts is to download
 410 and package them inside your app.</p></li>
 411 <li><p>You can use any framework you want,
 412 as long as it complies with Content Security Policies
 413 and other restrictions that Chrome Apps are enforced to follow.</p></li>
 414 <li><p>MVC frameworks make your life easier.
 415 Use them, specially if you want to build a non-trivial application.</p></li>
 416 </ul>
 417
 418 <h2 id="you_should_also_read">You should also read</h2>
 419
 420 <ul>
 421 <li><p><a href="angular_framework.html">Build Apps with AngularJS</a> tutorial</p></li>
 422 <li><p><a href="http://angularjs.org/">AngularJS Todo</a> tutorial</p></li>
 423 </ul>
 424
 425 <h2 id="what_39_s_next_">What's next?</h2>
 426
 427 <p>In <a href="app_codelab5_data.html">4 - Save and Fetch Data</a>,
 428 you will modify your Todo list app so that Todo items are saved.</p>