remoting/webapp/crd/js/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   /** @private {HTMLElement} */
  26   this.button_ = /** @type {HTMLElement} */
  27       (container.querySelector('button,.menu-button-activator'));
  28
  29   /** @private {HTMLElement} */
  30   this.menu_ = /** @type {HTMLElement} */ (container.querySelector('ul'));
  31
  32   /** @private {undefined|function():void} */
  33   this.onShow_ = opt_onShow;
  34
  35   /** @private {undefined|function():void} */
  36   this.onHide_ = opt_onHide;
  37
  38   /**
  39    * Create a "click-trap" div covering the entire document, but below the
  40    * menu in the z-order. This ensures the the menu can be closed by clicking
  41    * anywhere. Note that adding this event handler to <body> is not enough,
  42    * because elements can prevent event propagation; specifically, the client
  43    * plugin element does this.
  44    *
  45    * @private {HTMLElement}
  46    */
  47   this.clickTrap_ = /** @type {HTMLElement} */ (document.createElement('div'));
  48   this.clickTrap_.classList.add('menu-button-click-trap');
  49
  50   /** @type {remoting.MenuButton} */
  51   var that = this;
  52
  53   var closeHandler = function() {
  54     that.button_.classList.remove(remoting.MenuButton.BUTTON_ACTIVE_CLASS_);
  55     container.removeChild(that.clickTrap_);
  56     if (that.onHide_) {
  57       that.onHide_();
  58     }
  59   };
  60
  61   var onClick = function() {
  62     if (that.onShow_) {
  63       that.onShow_();
  64     }
  65     that.button_.classList.add(remoting.MenuButton.BUTTON_ACTIVE_CLASS_);
  66     container.appendChild(that.clickTrap_);
  67   };
  68
  69   this.button_.addEventListener('click', onClick, false);
  70   this.clickTrap_.addEventListener('click', closeHandler, false);
  71   this.menu_.addEventListener('click', closeHandler, false);
  72 };
  73
  74 /**
  75  * @return {HTMLElement} The button that activates the menu.
  76  */
  77 remoting.MenuButton.prototype.button = function() {
  78   return this.button_;
  79 };
  80
  81 /**
  82  * @return {HTMLElement} The menu.
  83  */
  84 remoting.MenuButton.prototype.menu = function() {
  85   return this.menu_;
  86 };
  87
  88 /**
  89  * Set or unset the selected state of an <li> menu item.
  90  * @param {Element} item The menu item to update.
  91  * @param {boolean} selected True to select the item, false to deselect it.
  92  * @return {void} Nothing.
  93  */
  94 remoting.MenuButton.select = function(item, selected) {
  95   if (selected) {
  96     item.classList.add('selected');
  97   } else {
  98     item.classList.remove('selected');
  99   }
 100 };
 101
 102 /** @const @private */
 103 remoting.MenuButton.BUTTON_ACTIVE_CLASS_ = 'active';