layout/forms/nsIComboboxControlFrame.h

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  37
  38 #ifndef nsIComboboxControlFrame_h___
  39 #define nsIComboboxControlFrame_h___
  40
  41 #include "nsQueryFrame.h"
  42 #include "nsFont.h"
  43
  44 class nsString;
  45 class nsIContent;
  46 class nsCSSFrameConstructor;
  47
  48 /**
  49   * nsIComboboxControlFrame is the common interface for frames of form controls. It
  50   * provides a uniform way of creating widgets, resizing, and painting.
  51   * @see nsLeafFrame and its base classes for more info
  52   */
  53 class nsIComboboxControlFrame : public nsQueryFrame
  54 {
  55 public:
  56   NS_DECL_QUERYFRAME_TARGET(nsIComboboxControlFrame)
  57
  58   /**
  59    * Indicates whether the list is dropped down
  60    */
  61   virtual PRBool IsDroppedDown() = 0;
  62
  63   /**
  64    * Shows or hides the drop down
  65    */
  66   virtual void ShowDropDown(PRBool aDoDropDown) = 0;
  67
  68   /**
  69    * Gets the Drop Down List
  70    */
  71   virtual nsIFrame* GetDropDown() = 0;
  72
  73   /**
  74    * Sets the Drop Down List
  75    */
  76   virtual void SetDropDown(nsIFrame* aDropDownFrame) = 0;
  77
  78   /**
  79    * Tells the combobox to roll up
  80    */
  81   virtual void RollupFromList() = 0;
  82
  83   /**
  84    * Redisplay the selected text (will do nothing if text has not changed).
  85    * This method might destroy this frame or any others that happen to be
  86    * around.  It might even run script.
  87    */
  88   NS_IMETHOD RedisplaySelectedText() = 0;
  89
  90   /**
  91    * Method for the listbox to set and get the recent index
  92    */
  93   virtual PRInt32 UpdateRecentIndex(PRInt32 aIndex) = 0;
  94
  95   /**
  96    *
  97    */
  98   virtual void AbsolutelyPositionDropDown() = 0;
  99
 100   /**
 101    * Notification that the content has been reset
 102    */
 103   virtual void OnContentReset() = 0;
 104
 105   /**
 106    * This returns the index of the item that is currently being displayed
 107    * in the display area. It may differ from what the currently Selected index
 108    * is in in the dropdown.
 109    *
 110    * Detailed explanation:
 111    * When the dropdown is dropped down via a mouse click and the user moves the mouse
 112    * up and down without clicking, the currently selected item is being tracking inside
 113    * the dropdown, but the combobox is not being updated. When the user selects items
 114    * with the arrow keys, the combobox is being updated. So when the user clicks outside
 115    * the dropdown and it needs to roll up it has to decide whether to keep the current
 116    * selection or not. This method is used to get the current index in the combobox to
 117    * compare it to the current index in the dropdown to see if the combox has been updated
 118    * and that way it knows whether to "cancel" the current selection residing in the
 119    * dropdown. Or whether to leave the selection alone.
 120    */
 121   virtual PRInt32 GetIndexOfDisplayArea() = 0;
 122 };
 123
 124 #endif
 125