tch*_*ore 2 javascript json backbone.js
我正在努力将一系列交互式教育应用程序从Flash转换为Javascript,我的团队正在计划使用Backbone.js作为框架.这些应用程序中的每一个基本上是一组场景,其向用户呈现信息和/或以问题或交互式小部件的形式提示某些交互.我们为应用程序考虑的基本结构如下:
当然,问题在于我是Backbone的新手.我已经完成了一些基本的教程,但是在将Backbone与静态JSON文件集成时遇到了问题.
假设我有以下非常基本的JSON文件,它显示了三个要显示的场景:
var scenes = [
{
"name": "Introduction",
"label": "Introduction",
"message": "Welcome to this app"
},
{
"name": "Exercise",
"label": "Exercise",
"message": "If this were a real app, there'd be some sort of exercise here"
},
{
"name": "Conclusion",
"label": "Conclusion",
"order": "Thank you for completing this app"
}
]
我需要的,以及我正在尝试做的是让Backbone生成导航小部件,让用户在这些场景之间导航并显示每个场景的消息.(这显然是真实应用程序的简化版本.)
这是我尝试过的:
// simplified object containing stage information
var stages = [
{
"name": "Introduction",
"label": "Introduction",
"message": "Welcome to this app"
},
{
"name": "Exercise",
"label": "Exercise",
"message": "If this were a real app, there'd be some sort of exercise here"
},
{
"name": "Conclusion",
"label": "Conclusion",
"order": "Thank you for completing this app"
}
];
$(function(){
// create model for each stage
StageModel = Backbone.Model.extend({});
// create collection for StageModel
StageModelList = Backbone.Collection.extend({
model: StageModel
});
var stageModelList = new StageModelList();
// create view for list of stages
StageListView = Backbone.View.extend({
el: $("#stageNav"),
initialize: function() {
// if stages are added later
stagemodellist.bind('add',this.createStageList, this);
},
events: {
'click .stageListItem' : 'selectStage'
},
createStageList: function(model) {
$("#stageList").append("<li class='stageListItem'>"+model.label+"</li>");
},
selectStage: function() {
this.router.navigate("stage/"+this.stage.name,true);
}
});
// create view for each stages
StageView = Backbone.View.extend({
el: $("#stage"),
initialize: function(options) {
// get stage variable from options
this.stage = this.options.stage;
// display stage
createOnEnter(this.stage);
},
createOnEnter: function(stage) {
$("#stageLabel").html(stage.label);
$("#stageMsg").html(stage.message);
}
});
// create router
AppRouter = Backbone.Router.extend({
initialize: function() {
Backbone.history.start();
// create collection
new StageModelList();
// create view when router is initialized
new StageListView();
// loop through stages and add each to StageModelList
for (var s in stages) {
StageModelList.add(stages[s]);
}
},
routes: {
"stage/:stage" : "renderStage"
},
renderStage: function(stage) {
// display StageView for this stage
new StageView({stage:stage});
}
});
var App = new AppRouter();
});
和HTML:
<!DOCTYPE html>
<html>
<head>
<script class="jsbin" src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
<script class="jsbin" src="http://documentcloud.github.com/underscore/underscore-min.js"></script>
<script class="jsbin" src="http://documentcloud.github.com/backbone/backbone.js"></script>
<script src="js/ilo4.js"></script>
<meta charset=utf-8 />
<title>JS Bin</title>
</head>
<body>
<p>My pathetic attempt at a Backbone.js app</p>
<div id="stageNav">
<ul id="stageList">
</ul>
</div>
<div id="stage">
<div id="stageLabel">
</div>
<div id="stageMsg">
</div>
</div>
</body>
</html>
(你也可以在这里看到一个jsbin版本:http://jsbin.com/iwerek/edit#javascript,html,live ).
不幸的是,现在这没有做任何事情.
我知道我在这里做了很多错事,还有一些我正在努力的问题:
一个
你实际上并不太远.
我已经克隆了你的jsbin并将其修好以便它可以工作:链接
我提交这个作为我对你问题的回答.我已经非常彻底地评论它,以解释发生了什么.
看看,希望它有所帮助.
编辑:到底是什么,我也将代码放在这里:
// simplified object containing stage information
window.stages = [
{
"name": "Introduction",
"label": "Introduction",
"message": "Welcome to this app"
},
{
"name": "Exercise",
"label": "Exercise",
"message": "If this were a real app, there'd be some sort of exercise here"
},
{
"name": "Conclusion",
"label": "Conclusion",
"message": "Thank you for completing this app"
}
];
$(function(){
// StageModel: no need to extend if you're not adding anything.
StageModel = Backbone.Model;
// StageCollection
StageCollection = Backbone.Collection.extend({
model: StageModel
});
// create view for list of stages
StageCollectionView = Backbone.View.extend({
el: $("#stageNav"),
initialize: function() {
// if stages are added later
this.collection.bind('add', this.createStageListItem, this);
},
events: {
'click .stageListItem' : 'selectStage'
},
// I'm adding the model's cid (generated by backbone) as the
// id of the 'li' here. Very non-ideal, as one of the points
// of backbone et al. is to keep from embedding and retrieving
// data from the DOM like this.
//
// Perhaps better would be to create a StageListItemView and
// render one for each model in the collection, perhaps like:
//
// createStageListItem: function(model) {
// this.$('#stageList').append(new StageListItemView({model: model});
// }
//
// where you have a StageListItemView that knows how to render
// itself and can handle click events and communicate with the
// collectionview via events.
//
// At any rate, this string-munging will suffice for now.
createStageListItem: function(model) {
this.$("#stageList").append("<li id=\"" + model.cid + "\" class='stageListItem'>" + model.get('label') + "</li>");
},
// Use backbone's event system, it's pretty awesome. Not to mention
// that it helps to decouple the parts of your app.
//
// And note that you can pass arguments when you trigger an event.
// So any event handler for the 'new-stage' event would receive
// this model as its first argument.
selectStage: function(event) {
var cid = $(event.target).attr('id');
this.trigger('new-stage', this.collection.getByCid(cid));
},
// This was a missing puzzle piece. Your StageCollectionView wasn't
// being rendered at all.
//
// Backbone convention is to call this function render, but you could
// call it whatever you want, as long as you, well, end up _calling_ it.
render: function() {
var self = this;
this.collection.each(function(model) {
self.createStageListItem(model);
});
return this;
}
});
// StageView,
StageView = Backbone.View.extend({
el: $("#stage"),
// We're going to assume here that we get passed a
// newStageEventSource property in the options and
// that it will fire a 'new-stage' event when we need
// to load a new stage.
initialize: function(options) {
this.eventSource = options.newStageEventSource;
this.eventSource.bind('new-stage', this.loadAndRenderStage, this);
},
// A load function to set the StageView's model.
load: function(model) {
this.model = model;
return this;
},
render: function() {
$("#stageLabel").html(this.model.get('label'));
$("#stageMsg").html(this.model.get('message'));
},
loadAndRenderStage: function(stage) {
this.load(stage);
this.render();
}
});
// Instatiate a StageCollection from the JSON list of stages.
// See Backbone docs for more, but you can pass in a list of
// hashes, and the Collection will use its model attribute to
// make the models for you
var stageCollection = new StageCollection(stages);
// View constructors take an options argument. Certain properties
// will automatically get attached to the view instance directly,
// like 'el', 'id', 'tagName', 'className', 'model', 'collection'.
var stageCollectionView = new StageCollectionView({
collection: stageCollection
});
// Instantiate the StageView, passing it the stageCollectionView in
// the options for it to listen to.
var stageView = new StageView({
newStageEventSource: stageCollectionView
});
// Last step, we need to call 'render' on the stageCollectionView
// to tell it to show itself.
stageCollectionView.render();
});