* What is a tray icon? *
Tray Icons are those you see near the clock,
such as the volume control, or DeskMenu.
You can add your application's icon to the system tray,
the small area on the right side of the task bar,
and react to mouse events occurring on your system tray icon.
* 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.
{*****************************************************}
unit TrayIcon;
interface
{
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.
}
uses
Windows, Messages, ShellApi, SysUtils, Classes, Graphics, Controls,
Forms, Dialogs, Menus;
{
This message is sent to the special, hidden window for shell
notification messages. Only derived classes might need to
know about it.
}
const
WM_CALLBACK_MESSAGE = WM_USER + 1;
type
TTrayIcon = class(TComponent)
private
fData: TNotifyIconData;
fIcon: TIcon;
fHint: string;
fPopupMenu: TPopupMenu;
fClicked: Boolean;
fOnClick: TNotifyEvent;
fOnDblClick: TNotifyEvent;
fOnMinimize: TNotifyEvent;
fOnMouseMove: TMouseMoveEvent;
fOnMouseDown: TMouseEvent;
fOnMouseUp: TMouseEvent;
fOnRestore: TNotifyEvent;
protected
procedure SetHint(const Hint: string); virtual;
procedure SetIcon(Icon: TIcon); virtual;
procedure AppMinimize(Sender: TObject);
procedure AppRestore(Sender: TObject);
procedure DoMenu; virtual;
procedure Click; virtual;
procedure DblClick; virtual;
procedure EndSession; virtual;
procedure DoMouseMove(Shift: TShiftState; X, Y: Integer); virtual;
procedure DoMouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
virtual;
procedure DoMouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
virtual;
procedure OnMessage(var Msg: TMessage); virtual;
procedure Changed; virtual;
property Data: TNotifyIconData read fData;
public
constructor Create(Owner: TComponent); override;
destructor Destroy; override;
procedure Minimize; virtual;
procedure Restore; virtual;
published
property Hint: string read fHint write SetHint;
property Icon: TIcon read fIcon write SetIcon;
property PopupMenu: TPopupMenu read fPopupMenu write fPopupMenu;
property OnClick: TNotifyEvent read fOnClick write fOnClick;
property OnDblClick: TNotifyEvent read fOnDblClick write fOnDblClick;
property OnMinimize: TNotifyEvent read fOnMinimize write fOnMinimize;
property OnMouseMove: TMouseMoveEvent read fOnMouseMove write fOnMouseMove;
property OnMouseDown: TMouseEvent read fOnMouseDown write fOnMouseDown;
property OnMouseUp: TMouseEvent read fOnMouseUp write fOnMouseUp;
property OnRestore: TNotifyEvent read fOnRestore write fOnRestore;
end;
procedure Register;
implementation
{
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);
if not (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;
if not 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;
if not (csDesigning in ComponentState) then
Shell_NotifyIcon(Nim_Delete, @fData);
inherited Destroy;
end;
{ Whenever any information changes, update the system tray. }
procedure TTrayIcon.Changed;
begin
if not (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 and not 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) and not 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;
procedure Register;
begin
RegisterComponents('Tempest', [TTrayIcon]);
end;
end.
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