remoting/webapp/menu_button.js

   1 // Copyright (c) 2012 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  * @fileoverview
   7  * Class representing a menu button and its associated menu items.
   8  */
   9
  10 'use strict';
  11
  12 /** @suppress {duplicate} */
  13 var remoting = remoting || {};
  14
  15 /**
  16  * @constructor
  17  * @param {Element} container The element containing the <button> and <ul>
  18  *     elements comprising the menu. It should have the "menu-button" class.
  19  * @param {function():void=} opt_onShow Optional callback invoked before the
  20  *     menu is shown.
  21  * @param {function():void=} opt_onHide Optional callback after before the
  22  *     menu is hidden.
  23  */
  24 remoting.MenuButton = function(container, opt_onShow, opt_onHide) {
  25   /**
  26    * @type {HTMLElement}
  27    * @private
  28    */
  29   this.button_ = /** @type {HTMLElement} */
  30       (container.querySelector('button,.menu-button-activator'));
  31
  32   /**
  33    * @type {HTMLElement}
  34    * @private
  35    */
  36   this.menu_ = /** @type {HTMLElement} */ (container.querySelector('ul'));
  37
  38   /**
  39    * @type {undefined|function():void}
  40    * @private
  41    */
  42   this.onShow_ = opt_onShow;
  43
  44   /**
  45    * @type {undefined|function():void}
  46    * @private
  47    */
  48   this.onHide_ = opt_onHide;
  49
  50   /**
  51    * Create a "click-trap" div covering the entire document, but below the
  52    * menu in the z-order. This ensures the the menu can be closed by clicking
  53    * anywhere. Note that adding this event handler to <body> is not enough,
  54    * because elements can prevent event propagation; specifically, the client
  55    * plugin element does this.
  56    *
  57    * @type {HTMLElement}
  58    * @private
  59    */
  60   this.clickTrap_ = /** @type {HTMLElement} */ (document.createElement('div'));
  61   this.clickTrap_.classList.add('menu-button-click-trap');
  62
  63   /** @type {remoting.MenuButton} */
  64   var that = this;
  65
  66   var closeHandler = function() {
  67     that.button_.classList.remove(remoting.MenuButton.BUTTON_ACTIVE_CLASS_);
  68     container.removeChild(that.clickTrap_);
  69     if (that.onHide_) {
  70       that.onHide_();
  71     }
  72   };
  73
  74   var onClick = function() {
  75     if (that.onShow_) {
  76       that.onShow_();
  77     }
  78     that.button_.classList.add(remoting.MenuButton.BUTTON_ACTIVE_CLASS_);
  79     container.appendChild(that.clickTrap_);
  80   };
  81
  82   this.button_.addEventListener('click', onClick, false);
  83   this.clickTrap_.addEventListener('click', closeHandler, false);
  84   this.menu_.addEventListener('click', closeHandler, false);
  85 };
  86
  87 /**
  88  * @return {HTMLElement} The button that activates the menu.
  89  */
  90 remoting.MenuButton.prototype.button = function() {
  91   return this.button_;
  92 };
  93
  94 /**
  95  * @return {HTMLElement} The menu.
  96  */
  97 remoting.MenuButton.prototype.menu = function() {
  98   return this.menu_;
  99 };
 100
 101 /**
 102  * Set or unset the selected state of an <li> menu item.
 103  * @param {Element} item The menu item to update.
 104  * @param {boolean} selected True to select the item, false to deselect it.
 105  * @return {void} Nothing.
 106  */
 107 remoting.MenuButton.select = function(item, selected) {
 108   if (selected) {
 109     /** @type {DOMTokenList} */(item.classList).add('selected');
 110   } else {
 111     /** @type {DOMTokenList} */(item.classList).remove('selected');
 112   }
 113 };
 114
 115 /** @const @private */
 116 remoting.MenuButton.BUTTON_ACTIVE_CLASS_ = 'active';