layout/forms/nsIComboboxControlFrame.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsIComboboxControlFrame_h___
   7 #define nsIComboboxControlFrame_h___
   8
   9 #include "nsQueryFrame.h"
  10 #include "nsFont.h"
  11
  12 class nsString;
  13 class nsIContent;
  14 class nsCSSFrameConstructor;
  15
  16 /**
  17   * nsIComboboxControlFrame is the common interface for frames of form controls. It
  18   * provides a uniform way of creating widgets, resizing, and painting.
  19   * @see nsLeafFrame and its base classes for more info
  20   */
  21 class nsIComboboxControlFrame : public nsQueryFrame
  22 {
  23 public:
  24   NS_DECL_QUERYFRAME_TARGET(nsIComboboxControlFrame)
  25
  26   /**
  27    * Indicates whether the list is dropped down
  28    */
  29   virtual bool IsDroppedDown() = 0;
  30
  31   /**
  32    * Shows or hides the drop down
  33    */
  34   virtual void ShowDropDown(bool aDoDropDown) = 0;
  35
  36   /**
  37    * Gets the Drop Down List
  38    */
  39   virtual nsIFrame* GetDropDown() = 0;
  40
  41   /**
  42    * Sets the Drop Down List
  43    */
  44   virtual void SetDropDown(nsIFrame* aDropDownFrame) = 0;
  45
  46   /**
  47    * Tells the combobox to roll up
  48    */
  49   virtual void RollupFromList() = 0;
  50
  51   /**
  52    * Redisplay the selected text (will do nothing if text has not changed).
  53    * This method might destroy this frame or any others that happen to be
  54    * around.  It might even run script.
  55    */
  56   NS_IMETHOD RedisplaySelectedText() = 0;
  57
  58   /**
  59    * Method for the listbox to set and get the recent index
  60    */
  61   virtual int32_t UpdateRecentIndex(int32_t aIndex) = 0;
  62
  63   /**
  64    * Notification that the content has been reset
  65    */
  66   virtual void OnContentReset() = 0;
  67
  68   /**
  69    * This returns the index of the item that is currently being displayed
  70    * in the display area. It may differ from what the currently Selected index
  71    * is in in the dropdown.
  72    *
  73    * Detailed explanation:
  74    * When the dropdown is dropped down via a mouse click and the user moves the mouse
  75    * up and down without clicking, the currently selected item is being tracking inside
  76    * the dropdown, but the combobox is not being updated. When the user selects items
  77    * with the arrow keys, the combobox is being updated. So when the user clicks outside
  78    * the dropdown and it needs to roll up it has to decide whether to keep the current
  79    * selection or not. This method is used to get the current index in the combobox to
  80    * compare it to the current index in the dropdown to see if the combox has been updated
  81    * and that way it knows whether to "cancel" the current selection residing in the
  82    * dropdown. Or whether to leave the selection alone.
  83    */
  84   virtual int32_t GetIndexOfDisplayArea() = 0;
  85 };
  86
  87 #endif
  88