content/browser/resources/media/tab_view.js

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * A TabView provides the ability to create tabs and switch between tabs. It's
   7  * responsible for creating the DOM and managing the visibility of each tab.
   8  * The first added tab is active by default and the others hidden.
   9  */
  10 var TabView = (function() {
  11   'use strict';
  12
  13   /**
  14    * @constructor
  15    * @param {Element} root The root DOM element containing the tabs.
  16    */
  17   function TabView(root) {
  18     this.root_ = root;
  19     this.ACTIVE_TAB_HEAD_CLASS_ = 'active-tab-head';
  20     this.ACTIVE_TAB_BODY_CLASS_ = 'active-tab-body';
  21     this.TAB_HEAD_CLASS_ = 'tab-head';
  22     this.TAB_BODY_CLASS_ = 'tab-body';
  23
  24     /**
  25      * A mapping for an id to the tab elements.
  26      * @type {!Object<string, !TabDom>}
  27      * @private
  28      */
  29     this.tabElements_ = {};
  30
  31     this.headBar_ = null;
  32     this.activeTabId_ = null;
  33     this.initializeHeadBar_();
  34   }
  35
  36   // Creates a simple object containing the tab head and body elements.
  37   function TabDom(h, b) {
  38     this.head = h;
  39     this.body = b;
  40   }
  41
  42   TabView.prototype = {
  43     /**
  44      * Adds a tab with the specified id and title.
  45      * @param {string} id
  46      * @param {string} title
  47      * @return {!Element} The tab body element.
  48      */
  49     addTab: function(id, title) {
  50       if (this.tabElements_[id])
  51         throw 'Tab already exists: ' + id;
  52
  53       var head = document.createElement('div');
  54       head.className = this.TAB_HEAD_CLASS_;
  55       head.textContent = title + ' [' + id + ']';
  56       head.title = title;
  57       this.headBar_.appendChild(head);
  58       head.addEventListener('click', this.switchTab_.bind(this, id));
  59
  60       var body = document.createElement('div');
  61       body.className = this.TAB_BODY_CLASS_;
  62       body.id = id;
  63       this.root_.appendChild(body);
  64
  65       this.tabElements_[id] = new TabDom(head, body);
  66
  67       if (!this.activeTabId_) {
  68         this.switchTab_(id);
  69       }
  70       return this.tabElements_[id].body;
  71     },
  72
  73     /** Removes the tab. @param {string} id */
  74     removeTab: function(id) {
  75       if (!this.tabElements_[id])
  76         return;
  77       this.tabElements_[id].head.parentNode.removeChild(
  78           this.tabElements_[id].head);
  79       this.tabElements_[id].body.parentNode.removeChild(
  80           this.tabElements_[id].body);
  81
  82       delete this.tabElements_[id];
  83       if (this.activeTabId_ == id) {
  84         this.switchTab_(Object.keys(this.tabElements_)[0]);
  85       }
  86     },
  87
  88     /**
  89      * Switches the specified tab into view.
  90      *
  91      * @param {string} activeId The id the of the tab that should be switched to
  92      *     active state.
  93      * @private
  94      */
  95     switchTab_: function(activeId) {
  96       if (this.activeTabId_ && this.tabElements_[this.activeTabId_]) {
  97         this.tabElements_[this.activeTabId_].body.classList.remove(
  98             this.ACTIVE_TAB_BODY_CLASS_);
  99         this.tabElements_[this.activeTabId_].head.classList.remove(
 100             this.ACTIVE_TAB_HEAD_CLASS_);
 101       }
 102       this.activeTabId_ = activeId;
 103       if (this.tabElements_[activeId]) {
 104         this.tabElements_[activeId].body.classList.add(
 105             this.ACTIVE_TAB_BODY_CLASS_);
 106         this.tabElements_[activeId].head.classList.add(
 107             this.ACTIVE_TAB_HEAD_CLASS_);
 108       }
 109     },
 110
 111     /** Initializes the bar containing the tab heads. */
 112     initializeHeadBar_: function() {
 113       this.headBar_ = document.createElement('div');
 114       this.root_.appendChild(this.headBar_);
 115       this.headBar_.style.textAlign = 'center';
 116     },
 117   };
 118   return TabView;
 119 })();