Question

当我在终端中键入open <this_filename.html>时，它会打开页面上已显示todolist模型列表的页面。怎么样？

以下是代码：

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <title>To-do App in Backbone.js</title>

  <!-- ========= -->
  <!--    CSS    -->
  <!-- ========= -->
  <style type="text/css">
    /* Hides bullet points from todo list */
    #todoapp ul {
      list-style-type: none;
    }
  </style>
</head>
<body>
  <!-- ========= -->
  <!-- Your HTML -->
  <!-- ========= -->

  <section id="todoapp">
    <header id="header">
      <h1>Todos</h1>
      <input id="new-todo" placeholder="What needs to be done?" autofocus>
    </header>
    <section id="main">
      <ul id="todo-list"></ul>
    </section>
  </section>
  <div>
    <p>Find the tutorial and code in <a href="http://adrianmejia.com/blog/2012/09/11/backbone-dot-js-for-absolute-beginners-getting-started/">here</a></p>
  </div>

  <!-- Templates -->
  <script type="text/template" id="item-template">
    <div class="view">
      <input class="toggle" type="checkbox">
      <label><%- title %></label>
    </div>
  </script>

  <!-- ========= -->
  <!-- Libraries -->
  <!-- ========= -->
  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js" type="text/javascript"></script>
  <script src="http://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.3.3/underscore-min.js" type="text/javascript"></script>
  <script src="http://cdnjs.cloudflare.com/ajax/libs/backbone.js/0.9.2/backbone-min.js" type="text/javascript"></script>
  <script src="http://cdnjs.cloudflare.com/ajax/libs/backbone-localstorage.js/1.0/backbone.localStorage-min.js" type="text/javascript"></script>

  <!-- =============== -->
  <!-- Javascript code -->
  <!-- =============== -->
  <script type="text/javascript">
    'use strict';

    var app = {}; // create namespace for our app

    //--------------
    // Models
    //--------------
    app.Todo = Backbone.Model.extend({
      defaults: {
        title: '',
        completed: false
      }
    });

    //--------------
    // Collections
    //--------------
    app.TodoList = Backbone.Collection.extend({
      model: app.Todo,
      localStorage: new Store("backbone-todo")
    });

    // instance of the Collection
    app.todoList = new app.TodoList();

    //--------------
    // Views
    //--------------

    // renders individual todo items list (li)
    app.TodoView = Backbone.View.extend({
      tagName: 'li',
      template: _.template($('#item-template').html()),
      render: function(){
        this.$el.html(this.template(this.model.toJSON()));
        return this; // enable chained calls
      }
    });

    // renders the full list of todo items calling TodoView for each one.
    app.AppView = Backbone.View.extend({
      el: '#todoapp',
      initialize: function () {
        this.input = this.$('#new-todo');
        app.todoList.on('add', this.addAll, this);
        app.todoList.on('reset', this.addAll, this);
        app.todoList.fetch(); // Loads list from local storage
      },
      events: {
        'keypress #new-todo': 'createTodoOnEnter'
      },
      createTodoOnEnter: function(e){
        if ( e.which !== 13 || !this.input.val().trim() ) { // ENTER_KEY = 13
          return;
        }
        app.todoList.create(this.newAttributes());
        this.input.val(''); // clean input box
      },
      addOne: function(todo){
        var view = new app.TodoView({model: todo});
        $('#todo-list').append(view.render().el);
      },
      addAll: function(){
        this.$('#todo-list').html(''); // clean the todo list
        app.todoList.each(this.addOne, this);
      },
      newAttributes: function(){
        return {
          title: this.input.val().trim(),
          completed: false
        }
      }
    });

    //--------------
    // Initializers
    //--------------

    app.appView = new app.AppView();

  </script>

</body>
</html>

在代码的底部，这一行：app.appView = new app.AppView();实例化AppView。是否自动调用reset函数？

我想我理解addAll和addOne方法是如何定义的，但我想知道它们首先是什么？如何在页面上呈现todoList？

Answer 1

<div class="flex-container-row lhs">
<div class="flex-container-v">
    <header class="flex-fixed">Header</header>
    <div class="flex-fill list-container">
        <ul>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
            <li>Item</li>
        </ul>
    </div>
    <footer class="flex-fixed">Footer</footer>
</div>
</div>

这会调用new app.AppView();的{{1}}函数。

initialize

监听器绑定到集合app.AppView的{{1}}和initialize: function () { // this is where addAll is called app.todoList.on('add', this.addAll, this); app.todoList.on('reset', this.addAll, this); app.todoList.fetch(); // Loads list from local storage },事件，并使用add作为回调。

在集合上调用reset时，它会向其添加新模型，触发app.todoList事件，然后触发回调this.addAll。

在我看来，使用最新的Backbone版本，它应该使用subquery这是.fetch()的更好版本：

add

listenTo

这个Backbone todo应用程序如何呈现页面的所有元素？

1 个答案: