{
* 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/
*
* Copyright (C) 2007-2012, Peter Johnson (www.delphidabbler.com).
*
* $Rev$
* $Date$
*
* Classes that manage and display popup menus associated with web browser
* controls.
}
unit UWBPopupMenus;
interface
uses
// Delphi
Classes, Generics.Collections, Types, Menus,
// Project
UCommandBars;
type
{
TWBPopupMenuQueryPopupEvent:
Type of event handler for TWBPopupMenu.OnQueryPopup event.
@param Sender [in] Object triggering event.
@param Cancel [in/out] Whether to cancel menu popup. Cancel is always
False when called. Handler can set Cancel to true to cancel popup.
}
TWBPopupMenuQueryPopupEvent = procedure(Sender: TObject; var Cancel: Boolean)
of object;
{
TWBPopupMenu:
Class that overrides popup menu. Designed for triggering from a web browser
control. Records HTML element under mouse cursor when menu triggered. Also
provides an event that enables popup to be cancelled.
}
TWBPopupMenu = class(TPopupMenu)
strict private
fHTMLElem: IDispatch; // Value of HTMLElem property
fOnQueryPopup: TWBPopupMenuQueryPopupEvent; // OnQueryPopup event handler
public
procedure Popup(X, Y: Integer); override;
{Override of method that displays popup menu. Triggers OnQueryPopup event
and cancels display of menu if event handler cancels the popup.
@param X [in] X coordinate of mouse cursor when menu triggered.
@param Y [in] Y coordinate of mouse cursor when menu triggered.
}
property HTMLElem: IDispatch read fHTMLElem write fHTMLElem;
{HTML element under mouse cursor when menu activated}
property OnQueryPopup: TWBPopupMenuQueryPopupEvent
read fOnQueryPopup write fOnQueryPopup;
{Event triggered before menu pops up. Handler can prevent display of menu
by setting event handler's Cancel parameter to true}
end;
{
TWBPopupMenuMgr:
Class used to manage the various popup menus associated with a web browser
control. Associates popup menus with various menu command ids supported by
web browser control.
}
TWBPopupMenuMgr = class(TComponent)
strict private
type
// Map of command bar ids to popup menu components
TMenuMap = TDictionary<TCommandBarID, TWBPopupMenu>;
var fMenus: TMenuMap; // Maps menu ids to popup menu objects
function GetMenu(const ID: TCommandBarID): TWBPopupMenu;
{Gets reference to menu associated with a command ID.
@param ID [in] ID of required menu.
@return Reference to required menu or nil if ID is not found.
}
public
constructor Create(AOwner: TComponent); override;
{Constructor. Sets up object.
@param AOwner [in] Component that owns this object.
}
destructor Destroy; override;
{Destructor. Tears down object.
}
function AddMenu(const ID: TCommandBarID): TWBPopupMenu;
{Creates a new menu, identifies it with an ID and adds it to the menu
list.
@param ID [in] ID of new menu.
@return Reference to new menu.
}
procedure Popup(const ID: TCommandBarID; const Pt: TPoint;
const Elem: IDispatch);
{Pops up menu of required kind for a specified HTML element.
@param ID [in] ID of menu to be displayed.
@param Pt [in] Point on screen where menu to be displayed.
@param Elem [in] HTML Element under mouse cursor when menu display
requested.
}
end;
{
TWBTempMenuItem:
Custom menu item type used for temporary menu items added to menus by
TWBDefaultPopupMenuWrapper. Associated action is freed when menu item is
freed.
}
TWBTempMenuItem = class(TMenuItem)
public
destructor Destroy; override;
{Destructor. Tears down object.
}
end;
implementation
{ TWBPopupMenu }
procedure TWBPopupMenu.Popup(X, Y: Integer);
{Override of method that displays popup menu. Triggers OnQueryPopup event and
cancels display of menu if event handler cancels the popup.
@param X [in] X coordinate of mouse cursor when menu triggered.
@param Y [in] Y coordinate of mouse cursor when menu triggered.
}
var
Cancel: Boolean; // flag indicates whether to cancel popup
begin
Cancel := False;
if Assigned(fOnQueryPopup) then
fOnQueryPopup(Self, Cancel);
if not Cancel then
inherited;
end;
{ TWBPopupMenuMgr }
function TWBPopupMenuMgr.AddMenu(const ID: TCommandBarID): TWBPopupMenu;
{Creates a new menu, identifies it with an ID and adds it to the menu list.
@param ID [in] ID of new menu.
@return Reference to new menu.
}
begin
Assert(not fMenus.ContainsKey(ID), ClassName + '.AddMenu: ID already exists');
// new menu item created here gets freed automatically when menu is destoyed
Result := TWBPopupMenu.Create(Self);
fMenus.Add(ID, Result);
end;
constructor TWBPopupMenuMgr.Create(AOwner: TComponent);
{Constructor. Sets up object.
@param AOwner [in] Component that owns this object.
}
begin
inherited;
// use default integer comparison and hash for TCommandBarID key in map
fMenus := TMenuMap.Create;
end;
destructor TWBPopupMenuMgr.Destroy;
{Destructor. Tears down object.
}
begin
fMenus.Free;
inherited;
end;
function TWBPopupMenuMgr.GetMenu(const ID: TCommandBarID): TWBPopupMenu;
{Gets reference to menu associated with a command ID.
@param ID [in] ID of required menu.
@return Reference to required menu or nil if ID is not found.
}
begin
Result := fMenus[ID];
end;
procedure TWBPopupMenuMgr.Popup(const ID: TCommandBarID; const Pt: TPoint;
const Elem: IDispatch);
{Pops up menu of required kind for a specified HTML element.
@param ID [in] ID of menu to be displayed.
@param Pt [in] Point on screen where menu to be displayed.
@param Elem [in] HTML Element under mouse cursor when menu display
requested.
}
var
Menu: TWBPopupMenu; // menu to popup
begin
Menu := GetMenu(ID);
if Assigned(Menu) then
begin
Menu.HTMLElem := Elem;
Menu.Popup(Pt.X, Pt.Y);
end;
end;
{ TWBTempMenuItem }
destructor TWBTempMenuItem.Destroy;
{Destructor. Tears down object.
}
begin
Action.Free; // free the associated action
inherited;
end;
end.
