{***************************************************** * How can I create a tray icon? *
Fortunately, creating an application that runs in the system tray is pretty easy - only one (API) function, Shell_NotifyIcon, is needed to accomplish the task. The function is defined in the ShellAPI unit and requires two parameters.
The first parameter (dwMessage) specifies the action to be taken. This parameter can be one of the following values:
NIM_ADD: Adds an icon to the status area. NIM_DELETE: Deletes an icon from the status area. NIM_MODIFY: Modifies an icon in the status area.
* To display an icon in the system tray, call Shell_NotifyIcon with the NIM_ADD flag.
* Any time you want to change the icon, tooltip text, etc, you can call Shell_NotifyIcon with NIM_MODIFY.
* Before your program terminates, call Shell_NotifyIcon with NIM_DELETE to clear your icon from the system tray.
The second parameter (pnid) is a pointer to a TNotifyIconData structure holding the information about the icon.
The TNotifyIconData structure contains the following elements:
cbSize: Passes the size of the NOTIFYICONDATA data type. Data Type: DWORD.
hWnd: Handle of the window used to receive the notification message. Data Type: HWND.
uId: Identifier of the icon in the status area. Data Type: UINT.
uFlags: Array of flags that indicate which of the other members contain valid data. Data Type: UINT. Value: Any combination of the following constants to indicate that the member of this structure is valid and will be used:
NIF_ICON: Passing this flag indicates that the value for the hIcon will be the icon that appears in the taskbar status area.
NIF_MESSAGE: Passing this flag indicates that the uCallBackMessage value will be used as the callback message.
NIF_TIP: Passing this flag indicates that the value of szTip will be used as the ToolTip for the icon in the taskbar status area.
uCallBackMessage: Identifier of the notification message sent to the window that is used to receive the messages. Data Type: UINT.
hIcon: Handle of the icon that is displayed in the taskbar status area. Data Type: HICON.
szTip: String to be used as the ToolTip text. Data Type: Fixed-length AnsiChar 64 bytes long.
{ A component to make it easier to create a system tray icon. Install this component in the Delphi IDE (Component, Install component) and drop it on a form, and the application automatically becomes a tray icon. This means that when the application is minimized, it does not minimize to a normal taskbar icon, but to the little system tray on the side of the taskbar. A popup menu is available from the system tray icon, and your application can process mouse events as the user moves the mouse over the system tray icon, clicks on the icon, etc.
Copyright ? 1996 Tempest Software. All rights reserved. You may use this software in an application without fee or royalty, provided this copyright notice remains intact. }
{ Create the component. At run-time, automatically add a tray icon with a callback to a hidden window. Use the application icon and title. } constructor TTrayIcon.Create(Owner: TComponent); begin inherited Create(Owner); fIcon := TIcon.Create; fIcon.Assign(Application.Icon); ifnot (csDesigning in ComponentState) then begin FillChar(fData, SizeOf(fData), 0); fData.cbSize := SizeOf(fData); fData.Wnd := AllocateHwnd(OnMessage); // handle to get notification message fData.hIcon := Icon.Handle; // icon to display StrPLCopy(fData.szTip, Application.Title, SizeOf(fData.szTip) - 1); fData.uFlags := Nif_Icon or Nif_Message; if Application.Title <> '' then fData.uFlags := fData.uFlags or Nif_Tip; fData.uCallbackMessage := WM_CALLBACK_MESSAGE; ifnot Shell_NotifyIcon(NIM_ADD, @fData) then // add it raise EOutOfResources.Create('Cannot create shell notification icon'); { Replace the application's minimize and restore handlers with special ones for the tray. The TrayIcon component has its own OnMinimize and OnRestore events that the user can set. } Application.OnMinimize := AppMinimize; Application.OnRestore := AppRestore; end; end;
{ Remove the icon from the system tray.} destructor TTrayIcon.Destroy; begin fIcon.Free; ifnot (csDesigning in ComponentState) then Shell_NotifyIcon(Nim_Delete, @fData); inherited Destroy; end;
{ Whenever any information changes, update the system tray. } procedure TTrayIcon.Changed; begin ifnot (csDesigning in ComponentState) then Shell_NotifyIcon(NIM_MODIFY, @fData); end;
{ When the Application is minimized, minimize to the system tray.} procedure TTrayIcon.AppMinimize(Sender: TObject); begin Minimize end;
{ When restoring from the system tray, restore the application. } procedure TTrayIcon.AppRestore(Sender: TObject); begin Restore end;
{ Message handler for the hidden shell notification window. Most messages use Wm_Callback_Message as the Msg ID, with WParam as the ID of the shell notify icon data. LParam is a message ID for the actual message, e.g., Wm_MouseMove. Another important message is Wm_EndSession, telling the shell notify icon to delete itself, so Windows can shut down.
Send the usual Delphi events for the mouse messages. Also interpolate the OnClick event when the user clicks the left button, and popup the menu, if there is one, for right click events. }
procedure TTrayIcon.OnMessage(var Msg: TMessage); { Return the state of the shift keys. } function ShiftState: TShiftState; begin Result := []; if GetKeyState(VK_SHIFT) < 0 then Include(Result, ssShift); if GetKeyState(VK_CONTROL) < 0 then Include(Result, ssCtrl); if GetKeyState(VK_MENU) < 0 then Include(Result, ssAlt); end; var Pt: TPoint; Shift: TShiftState; begin case Msg.Msg of Wm_QueryEndSession: Msg.Result := 1; Wm_EndSession: if TWmEndSession(Msg).EndSession then EndSession; Wm_Callback_Message: case Msg.lParam of WM_MOUSEMOVE: begin Shift := ShiftState; GetCursorPos(Pt); DoMouseMove(Shift, Pt.X, Pt.Y); end; WM_LBUTTONDOWN: begin Shift := ShiftState + [ssLeft]; GetCursorPos(Pt); DoMouseDown(mbLeft, Shift, Pt.X, Pt.Y); fClicked := True; end; WM_LBUTTONUP: begin Shift := ShiftState + [ssLeft]; GetCursorPos(Pt); if fClicked then begin fClicked := False; Click; end; DoMouseUp(mbLeft, Shift, Pt.X, Pt.Y); end; WM_LBUTTONDBLCLK: DblClick; WM_RBUTTONDOWN: begin Shift := ShiftState + [ssRight]; GetCursorPos(Pt); DoMouseDown(mbRight, Shift, Pt.X, Pt.Y); DoMenu; end; WM_RBUTTONUP: begin Shift := ShiftState + [ssRight]; GetCursorPos(Pt); DoMouseUp(mbRight, Shift, Pt.X, Pt.Y); end; WM_RBUTTONDBLCLK: DblClick; WM_MBUTTONDOWN: begin Shift := ShiftState + [ssMiddle]; GetCursorPos(Pt); DoMouseDown(mbMiddle, Shift, Pt.X, Pt.Y); end; WM_MBUTTONUP: begin Shift := ShiftState + [ssMiddle]; GetCursorPos(Pt); DoMouseUp(mbMiddle, Shift, Pt.X, Pt.Y); end; WM_MBUTTONDBLCLK: DblClick; end; end; end;
{ Set a new hint, which is the tool tip for the shell icon. } procedure TTrayIcon.SetHint(const Hint: string); begin if fHint <> Hint then begin fHint := Hint; StrPLCopy(fData.szTip, Hint, SizeOf(fData.szTip) - 1); if Hint <> '' then fData.uFlags := fData.uFlags or Nif_Tip else fData.uFlags := fData.uFlags andnot Nif_Tip; Changed; end; end;
{ Set a new icon. Update the system tray. } procedure TTrayIcon.SetIcon(Icon: TIcon); begin if fIcon <> Icon then begin fIcon.Assign(Icon); fData.hIcon := Icon.Handle; Changed; end; end;
{ When the user right clicks the icon, call DoMenu. If there is a popup menu, and if the window is minimized, then popup the menu. }
procedure TTrayIcon.DoMenu; var Pt: TPoint; begin if (fPopupMenu <> nil) andnot IsWindowVisible(Application.Handle) then begin GetCursorPos(Pt); fPopupMenu.Popup(Pt.X, Pt.Y); end; end;
procedure TTrayIcon.Click; begin if Assigned(fOnClick) then fOnClick(Self); end;
procedure TTrayIcon.DblClick; begin if Assigned(fOnDblClick) then fOnDblClick(Self); end;
procedure TTrayIcon.DoMouseMove(Shift: TShiftState; X, Y: Integer); begin if Assigned(fOnMouseMove) then fOnMouseMove(Self, Shift, X, Y); end;
procedure TTrayIcon.DoMouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Integer); begin if Assigned(fOnMouseDown) then fOnMouseDown(Self, Button, Shift, X, Y); end;
procedure TTrayIcon.DoMouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Integer); begin if Assigned(fOnMouseUp) then fOnMouseUp(Self, Button, Shift, X, Y); end;
{ When the application minimizes, hide it, so only the icon in the system tray is visible. } procedure TTrayIcon.Minimize; begin ShowWindow(Application.Handle, SW_HIDE); if Assigned(fOnMinimize) then fOnMinimize(Self); end;
{ Restore the application by making its window visible again, which is a little weird since its window is invisible, having no height or width, but that's what determines whether the button appears on the taskbar. }
procedure TTrayIcon.Restore; begin ShowWindow(Application.Handle, SW_RESTORE); if Assigned(fOnRestore) then fOnRestore(Self); end;
{ Allow Windows to exit by deleting the shell notify icon. } procedure TTrayIcon.EndSession; begin Shell_NotifyIcon(Nim_Delete, @fData); end;
procedureRegister; begin RegisterComponents('Tempest', [TTrayIcon]); end;