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 nsPresContext;
  45 class nsString;
  46 class nsIContent;
  47 class nsCSSFrameConstructor;
  48
  49 /**
  50   * nsIComboboxControlFrame is the common interface for frames of form controls. It
  51   * provides a uniform way of creating widgets, resizing, and painting.
  52   * @see nsLeafFrame and its base classes for more info
  53   */
  54 class nsIComboboxControlFrame : public nsQueryFrame
  55 {
  56 public:
  57   NS_DECLARE_FRAME_ACCESSOR(nsIComboboxControlFrame)
  58
  59   /**
  60    * Indicates whether the list is dropped down
  61    */
  62   virtual PRBool IsDroppedDown() = 0;
  63
  64   /**
  65    * Shows or hides the drop down
  66    */
  67   virtual void ShowDropDown(PRBool aDoDropDown) = 0;
  68
  69   /**
  70    * Gets the Drop Down List
  71    */
  72   virtual nsIFrame* GetDropDown() = 0;
  73
  74   /**
  75    * Sets the Drop Down List
  76    */
  77   virtual void SetDropDown(nsIFrame* aDropDownFrame) = 0;
  78
  79   /**
  80    * Tells the combobox to roll up
  81    */
  82   virtual void RollupFromList() = 0;
  83
  84   /**
  85    * Redisplay the selected text (will do nothing if text has not changed).
  86    * This method might destroy this frame or any others that happen to be
  87    * around.  It might even run script.
  88    */
  89   NS_IMETHOD RedisplaySelectedText() = 0;
  90
  91   /**
  92    * Method for the listbox to set and get the recent index
  93    */
  94   virtual PRInt32 UpdateRecentIndex(PRInt32 aIndex) = 0;
  95
  96   /**
  97    *
  98    */
  99   virtual void AbsolutelyPositionDropDown() = 0;
 100
 101   /**
 102    * Notification that the content has been reset
 103    */
 104   virtual void OnContentReset() = 0;
 105
 106   /**
 107    * This returns the index of the item that is currently being displayed
 108    * in the display area. It may differ from what the currently Selected index
 109    * is in in the dropdown.
 110    *
 111    * Detailed explanation:
 112    * When the dropdown is dropped down via a mouse click and the user moves the mouse
 113    * up and down without clicking, the currently selected item is being tracking inside
 114    * the dropdown, but the combobox is not being updated. When the user selects items
 115    * with the arrow keys, the combobox is being updated. So when the user clicks outside
 116    * the dropdown and it needs to roll up it has to decide whether to keep the current
 117    * selection or not. This method is used to get the current index in the combobox to
 118    * compare it to the current index in the dropdown to see if the combox has been updated
 119    * and that way it knows whether to "cancel" the current selection residing in the
 120    * dropdown. Or whether to leave the selection alone.
 121    */
 122   virtual PRInt32 GetIndexOfDisplayArea() = 0;
 123 };
 124
 125 #endif
 126