前言
公司的Fish框架在架构方面采用了Backbone的MVC模式，本项目组也曾使用了Fish来开发一套产品，但由于开发时间的重叠，框架组做了一套标准，我组也搞了一套，可能并不成熟。等年中本人进去的时候此产品也就接近尾声了，只剩下修修补补，所以对此框架并不怎么理解。趁着年底，将Backbone的经典案例Todos敲了一遍，并将自己的一点理解加在了注释上。（英文原注解对功能介绍得已经很直白，本人加了一点其他浅显的中文注解）
页面截图
代码解析
核心文件：todos.js
// An example Backbone application contributed by
// [Jérôme Gravel-Niquet](http://jgn.me/). This demo uses a simple
// [LocalStorage adapter](backbone.localStorage.html)
// to persist Backbone models within your browser.
// Load the application once the DOM is ready, using `jQuery.ready`:
$(function(){
// Todo Model
// ----------
// Our basic **Todo** model has `title`, `order`, and `done` attributes.
var Todo = Backbone.Model.extend({
// Default attributes for the todo item.
// 也可直接定义 defaults: {title: "XX",...}
defaults: function() {
return {
title: "empty todo...",
order: Todos.nextOrder(),
done: false
};
},
// Toggle the `done` state of this todo item.
toggle: function() {
this.save({done: !this.get("done")});
}
});
// Todo Collection
// ---------------
// The collection of todos is backed by *localStorage* instead of a remote
// server.
var TodoList = Backbone.Collection.extend({
// Reference to this collection's model.
model: Todo,
// Save all of the todo items under the `"todos-backbone"` namespace.
localStorage: new Backbone.LocalStorage("todos-backbone"),
// Filter down the list of all todo items that are finished.
done: function() {
return this.where({done: true});
},
// Filter down the list to only todo items that are still not finished.
remaining: function() {
return this.where({done: false});
},
// We keep the Todos in sequential order, despite being saved by unordered
// GUID in the database. This generates the next order number for new items.
nextOrder: function() {
if (!this.length) return 1;
return this.last().get('order') + 1;
},
// Todos are sorted by their original insertion order.
comparator: 'order'
});
// Create our global collection of **Todos**.
// 省略了()
var Todos = new TodoList;
// Todo Item View
// --------------
// The DOM element for a todo item...
var TodoView = Backbone.View.extend({
//... is a list tag.
// 视图Dom元素类型，默认是 div。同样也可设置id,className等
// 如果 el 属性有值时，忽略该属性
tagName: "li",
// Cache the template function for a single item.
// Underscore 模版
template: _.template($('#item-template').html()),
// The DOM events specific to an item.
// 使用事件委托的方式，委托在el上，提高性能
events: {
"click .toggle" : "toggleDone",
"dblclick .view" : "edit",
"click a.destroy" : "clear",
"keypress .edit" : "updateOnEnter",
"blur .edit" : "close"
},
// The TodoView listens for changes to its model, re-rendering. Since there's
// a one-to-one correspondence between a **Todo** and a **TodoView** in this
// app, we set a direct reference on the model for convenience.
initialize: function() {
// 设置事件监听，View监听model的事件
// 例如当model触发destroy事件时，执行View的remove方法移除该View
// model属性由new TodoView({model: todo})创建所赋
this.listenTo(this.model, 'change', this.render);
this.listenTo(this.model, 'destroy', this.remove);
},
// Re-render the titles of the todo item.
render: function() {
// $el: 视图元素的缓存jQuery对象
// 渲染到页面上
this.$el.html(this.template(this.model.toJSON()));
this.$el.toggleClass('done', this.model.get('done'));
// 创建公共变量 input
this.input = this.$('.edit');
return this;
},
// Toggle the `"done"` state of the model.
toggleDone: function() {
this.model.toggle();
},
// Switch this view into `"editing"` mode, displaying the input field.
edit: function() {
this.$el.addClass("editing");
this.input.focus();
},
// Close the `"editing"` mode, saving changes to the todo.
close: function() {
var value = this.input.val();
if (!value) {
this.clear();
} else {
this.model.save({title: value});
this.$el.removeClass("editing");
}
},
// If you hit `enter`, we're through editing the item.
updateOnEnter: function(e) {
if (e.keyCode == 13) this.close();
},
// Remove the item, destroy the model.
clear: function() {
this.model.destroy();
}
});
// The Application
// ---------------
// Our overall **AppView** is the top-level piece of UI.
var AppView = Backbone.View.extend({
// Instead of generating a new element, bind to the existing skeleton of
// the App already present in the HTML.
// DOM 元素（el 属性），可以从视图的 tagName, className, id 和 attributes 创建，
// 默认为空div
el: $("#todoapp"),
// Our template for the line of statistics at the bottom of the app.
statsTemplate: _.template($('#stats-template').html()),
// Delegated events for creating new items, and clearing completed ones.
events: {
"keypress #new-todo": "createOnEnter",
"click #clear-completed": "clearCompleted",
"click #toggle-all": "toggleAllComplete"
},
// At initialization we bind to the relevant events on the `Todos`
// collection, when items are added or changed. Kick things off by
// loading any preexisting todos that might be saved in *localStorage*.
initialize: function() {
// 定义公共变量
this.input = this.$("#new-todo");
this.allCheckbox = this.$("#toggle-all")[0];
this.listenTo(Todos, 'add', this.addOne);
this.listenTo(Todos, 'reset', this.addAll);
this.listenTo(Todos, 'all', this.render);
this.footer = this.$('footer');
this.main = $('#main');
// 从localStorage中取数据todos
Todos.fetch();
},
// Re-rendering the App just means refreshing the statistics -- the rest
// of the app doesn't change.
render: function() {
var done = Todos.done().length;
var remaining = Todos.remaining().length;
if (Todos.length) {
this.main.show();
this.footer.show();
this.footer.html(this.statsTemplate({done: done, remaining: remaining}));
} else {
this.main.hide();
this.footer.hide();
}
this.allCheckbox.checked = !remaining;
},
// Add a single todo item to the list by creating a view for it, and
// appending its element to the `<ul>`.
addOne: function(todo) {
var view = new TodoView({model: todo});
this.$("#todo-list").append(view.render().el);
},
// Add all items in the **Todos** collection at once.
addAll: function() {
Todos.each(this.addOne, this);
},
// If you hit return in the main input field, create new **Todo** model,
// persisting it to *localStorage*.
createOnEnter: function(e) {
if (e.keyCode != 13) return;
if (!this.input.val()) return;
Todos.create({title: this.input.val()});
this.input.val('');
},
// Clear all done todo items, destroying their models.
clearCompleted: function() {
_.invoke(Todos.done(), 'destroy');
return false;
},
toggleAllComplete: function () {
var done = this.allCheckbox.checked;
Todos.each(function (todo) { todo.save({'done': done}); });
}
});
// Finally, we kick things off by creating the **App**.
var App = new AppView;
});
完整文件
github: 点此可取
