Using hotkey even if window hide in tray. Is it possible in Delphi?

Question

I need to hide a form to the system tray, but in the same time I want to use hotkey, such a "ctrl+3" to get text from tEdit on my hiden form being inserted to Firefox SendText(edit1.Text); // in such method'. I know how to insert text, but i don't know anything about hotkeys/ Any suggestions? Thank you. Code of text inserting below

procedure SendText(const Value: WideString);
var
  I: Integer;
  S: WideString;
  TI: TInput;
  KI: TKeybdInput;
const
  KEYEVENTF_UNICODE = $0004;
begin
  S := WideUpperCase(Value); 
  TI.Itype := INPUT_KEYBOARD;
  for I := 1 to Length(S) do
  begin
    KI.wVk := 0;
    KI.dwFlags := KEYEVENTF_UNICODE;
    KI.wScan := Ord(S[I]);
    TI.ki := KI;
    SendInput(1, TI, SizeOf(TI));
  end;
end;

Answer 1

To Register a system wide hotkey you must use the RegisterHotKey and UnRegisterHotKey functions.

Check this sample

type
  TForm125 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    HotKey1 : Integer;
    procedure WMHotKey(var Msg: TWMHotKey); message WM_HOTKEY;
  public

  end;

var
  Form125: TForm125;

implementation

{$R *.dfm}


procedure TForm125.FormCreate(Sender: TObject);
begin
  HotKey1 := GlobalAddAtom('MyAppHotkey1');//create a unique value for identify the hotkey
  if not RegisterHotKey(Handle, HotKey1, MOD_CONTROL, VK_F1) then //register the hotkey CTRL + F1
   ShowMessage('Sorry can not register the hotkey');
end;

procedure TForm125.FormDestroy(Sender: TObject);
begin
  UnRegisterHotKey(Handle, HotKey1);//unregister the hotkey
  GlobalDeleteAtom(HotKey1);//remove the atom
end;

procedure TForm125.WMHotKey(var Msg: TWMHotKey);
begin
  if Msg.HotKey = HotKey1 then
    ShowMessage('Hello'); // do your stuff
end;

Just be carefull about the key combination which you choose, because can be used internally for another app. for example the combination Ctrl Number is used by Firefox to switch the tabs.