gecko-dev/layout/forms/nsIComboboxControlFrame.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsIComboboxControlFrame_h___
#define nsIComboboxControlFrame_h___
#include "nsQueryFrame.h"
#include "nsFont.h"
class nsString;
class nsIContent;
class nsCSSFrameConstructor;
/**
* nsIComboboxControlFrame is the common interface for frames of form controls. It
* provides a uniform way of creating widgets, resizing, and painting.
* @see nsLeafFrame and its base classes for more info
*/
class nsIComboboxControlFrame : public nsQueryFrame
{
public:
NS_DECL_QUERYFRAME_TARGET(nsIComboboxControlFrame)
/**
* Indicates whether the list is dropped down
*/
virtual bool IsDroppedDown() = 0;
/**
* Shows or hides the drop down
*/
virtual void ShowDropDown(bool aDoDropDown) = 0;
/**
* Gets the Drop Down List
*/
virtual nsIFrame* GetDropDown() = 0;
/**
* Sets the Drop Down List
*/
virtual void SetDropDown(nsIFrame* aDropDownFrame) = 0;
/**
* Tells the combobox to roll up
*/
virtual void RollupFromList() = 0;
/**
* Redisplay the selected text (will do nothing if text has not changed).
* This method might destroy this frame or any others that happen to be
* around. It might even run script.
*/
NS_IMETHOD RedisplaySelectedText() = 0;
/**
* Method for the listbox to set and get the recent index
*/
virtual PRInt32 UpdateRecentIndex(PRInt32 aIndex) = 0;
/**
*
*/
virtual void AbsolutelyPositionDropDown() = 0;
/**
* Notification that the content has been reset
*/
virtual void OnContentReset() = 0;
/**
* This returns the index of the item that is currently being displayed
* in the display area. It may differ from what the currently Selected index
* is in in the dropdown.
*
* Detailed explanation:
* When the dropdown is dropped down via a mouse click and the user moves the mouse
* up and down without clicking, the currently selected item is being tracking inside
* the dropdown, but the combobox is not being updated. When the user selects items
* with the arrow keys, the combobox is being updated. So when the user clicks outside
* the dropdown and it needs to roll up it has to decide whether to keep the current
* selection or not. This method is used to get the current index in the combobox to
* compare it to the current index in the dropdown to see if the combox has been updated
* and that way it knows whether to "cancel" the current selection residing in the
* dropdown. Or whether to leave the selection alone.
*/
virtual PRInt32 GetIndexOfDisplayArea() = 0;
};
#endif