（六）backbone - API学习 - Backbone路由

Backbone路由本质

Backbone路由分为两个大块，Router以及History用户在Router中定义相关规则，然后开启history.start进行路由监控，执行默认的回调所以，Router本身除了定义路由规则，全部调用的是Backbone.history的方法Backbone.History的主要关注点事实上是 popstate(hashChange)的回调checkUrl，无论我们触发navigate或者点击浏览器后退皆是进入此入口，再回调至Router定义的回调，从而实现相关逻辑

•创建规则

 1 var App = Backbone.Router.extend({ 2     routes: { 3       "": "index",    // #index 4       "index": "index",    // #index 5       "detail": "detail"    // #detail 6     }, 7     index: function () { 8       var index = new Index(this.interface); 9   10    },11    detail: function () {12      var detail = new Detail(this.interface);13  14    },15    initialize: function () {16  17    },18    interface: {19      forward: function (url) {20        window.location.href = ('#' + url).replace(/^#+/, '#');21      }22  23    }24 });

•开启路由控制

Backbone.history.start();

Backbone.history源码分析

history构造函数

 1 var History = Backbone.History = function () { 2   this.handlers = []; 3   _.bindAll(this, 'checkUrl'); 4  5   // Ensure that `History` can be used outside of the browser. 6   if (typeof window !== 'undefined') { 7     this.location = window.location; 8     this.history = window.history; 9   }10 };

history.start 函数

 1 start: function(options) { 2       if (History.started) throw new Error("Backbone.history has already been started"); 3       History.started = true; 4  5       // Figure out the initial configuration. Do we need an iframe? 6       // Is pushState desired ... is it available? 7       this.options          = _.extend({root: '/'}, this.options, options); 8       this.root             = this.options.root; 9       this._wantsHashChange = this.options.hashChange !== false;10       this._wantsPushState  = !!this.options.pushState;11       this._haspushState    = !!(this.options.pushState && this.history && this.history.pushState);12       var fragment          = this.getFragment();13       var docMode           = document.documentMode;14       var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));15 16       // Normalize root to always include a leading and trailing slash.17       this.root = ('/' + this.root + '/').replace(rootStripper, '/');18 19       // 老版本ie以及希望使用hashChange, 使用iframe实现20       if (oldIE && this._wantsHashChange) {21         var frame = Backbone.$('<iframe src="javascript:0" tabindex="-1">');22         this.iframe = frame.hide().appendTo('body')[0].contentWindow;23         this.navigate(fragment);24       }25       26       // Depending on whether we're using pushState or hashes, and whether27       // 'onhashchange' is supported, determine how we check the URL state.28       if (this._hasPushState) {29         Backbone.$(window).on('popstate', this.checkUrl);30       } else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {31         Backbone.$(window).on('hashchange', this.checkUrl);32       } else if (this._wantsHashChange) {33         this._checkUrlInterval = setInterval(this.checkUrl, this.interval);34       }              /* 取决于选择hash还是pushState  　　　　　　如果使用 pushState，调用方法           Backbone.history.start({ pushState: true });           */35 36       // Determine if we need to change the base url, for a pushState link37       // opened by a non-pushState browser.38       this.fragment = fragment;39       var loc = this.location;40 41       // Transition from hashChange to pushState or vice versa if both are42       // requested.43       if (this._wantsHashChange && this._wantsPushState) {44 45         // If we've started off with a route from a `pushState`-enabled46         // browser, but we're currently in a browser that doesn't support it...47         if (!this._hasPushState && !this.atRoot()) {48           this.fragment = this.getFragment(null, true);49           this.location.replace(this.root + '#' + this.fragment);50           // Return immediately as browser will do redirect to new url51           return true;52 53         // Or if we've started out with a hash-based route, but we're currently54         // in a browser where it could be `pushState`-based instead...55         } else if (this._hasPushState && this.atRoot() && loc.hash) {56           this.fragment = this.getHash().replace(routeStripper, '');57           this.history.replaceState({}, document.title, this.root + this.fragment);58         }59 60       }61 62       if (!this.options.silent) return this.loadUrl();63     }

统一入口 loadUrl

loadUrl: function (fragmentOverride) {  var fragment = this.fragment = this.getFragment(fragmentOverride);  var matched = _.any(this.handlers, function (handler) {      // handlers是routes定义的集合，实例化Router时导入    if (handler.route.test(fragment)) {      handler.callback(fragment);      return true;    }  });  return matched;}