How to hide firemonkey application button from Taskbar (XE4)?

Question

According to this question it is possible to hide fmx taskbar icon by changing window style to WS_EX_TOOLWINDOW. In XE2 and XE3 this code works:

uses FMX.Platform.Win, Winapi.Windows;

procedure TForm1.Button1Click(Sender: TObject);
var h:THandle;
begin
  h := FmxHandleToHWND(Handle);
  ShowWindow(h, SW_HIDE);
  SetWindowLong(h, GWL_EXSTYLE, GetWindowLong(h, GWL_EXSTYLE) or WS_EX_TOOLWINDOW);
  ShowWindow(h, SW_SHOW);
end;

In XE4 this solution does not work (application button should become hidden but nothing happens). any body have any idea?

Thanks.

Answer 1

Just tried this in XE7 and of course it didn't work. However a little look into FMX.PlatformWin shows the application handle is now exposed through the ApplicationHWND function, so the code that works on XE7 (don't forget to include unit FMX.Platform.Win and Winapi.Windows) is...

procedure HideAppOnTaskbar (AMainForm : TForm);
var
  AppHandle : HWND;
begin
  AppHandle := ApplicationHWND; 
  ShowWindow(AppHandle, SW_HIDE);
  SetWindowLong(AppHandle, GWL_EXSTYLE, GetWindowLong(AppHandle, GWL_EXSTYLE) and (not     WS_EX_APPWINDOW) or WS_EX_TOOLWINDOW);
  //ShowWindow(AppHandle, SW_SHOW);
end;

The ShowWindow at the end is optional - it seems to make no difference. You can remove the extended styles and restore the WS_EX_APPWINDOW style to show the toolbar icon again.

Answer 2

It seems that in XE4 FM apps there is no more handle for the application object. So we need to get the parent of the main form. Below two small methods to hide/show your app on the taskbar.

procedure HideAppOnTaskbar (AMainForm : TForm);
var
  AppHandle : HWND;
begin
  AppHandle := GetParent(FmxHandleToHWND(AMainForm.Handle));
  ShowWindow(AppHandle, SW_HIDE);
  SetWindowLong(AppHandle, GWL_EXSTYLE, GetWindowLong(AppHandle, GWL_EXSTYLE) or WS_EX_TOOLWINDOW);
end;

procedure ShowAppOnTaskbar (AMainForm : TForm);
var
  AppHandle : HWND;
begin
  AppHandle := GetParent(FmxHandleToHWND(AMainForm.Handle));
  ShowWindow(AppHandle, SW_HIDE);
  SetWindowLong(AppHandle, GWL_EXSTYLE, GetWindowLong(AppHandle, GWL_EXSTYLE) and (not WS_EX_TOOLWINDOW));
  ShowWindow(AppHandle, SW_SHOW);
end;

We could also have used "Application.MainForm" instead of passing the mainform, but this variable is not assigned during the "OnCreate" Event of the mainform.

So in your "OnCreate" Event off your mainform you can simply write:

procedure TMyMainForm.FormCreate(Sender: TObject);
begin
  HideAppOnTaskbar (self);
end;

Answer 3

procedure HideAppOnTaskbar;
var
  appHandle: HWND;
  pid, current_pid: DWORD;
  name: String;

begin
  //ShowWindow(FindWindowA('TFMAppClass', nil), SW_HIDE);

  name := ChangeFileExt(ExtractFileName(ParamStr(0)), '');

  appHandle := 0;
  pid := 0;
  current_pid := GetCurrentProcessId();
  repeat
  begin
    //appHandle := FindWindowExA(0, appHandle, 'TFMAppClass', nil);
    appHandle := FindWindowExA(0, appHandle, 'TFMAppClass', PAnsiChar(AnsiString(name)));
    if (appHandle>0) then
    begin
      GetWindowThreadProcessId(appHandle, pid);
      if (current_pid = pid) then break;
    end;
  end
  until (appHandle>0);

  //SetParent(FmxHandleToHWND(Handle), nil);
  ShowWindow(appHandle, SW_HIDE);

end;

Answer 4

HWND hWnd = NULL;
DWORD pid, current_pid = GetCurrentProcessId();
do 
{
    hWnd = FindWindowExA(NULL, hWnd, "TFMAppClass", NULL);
    if(hWnd)
    {
        GetWindowThreadProcessId(hWnd, &pid);
        if(current_pid == pid)
            break;
    }
} while(hWnd);

::SetParent(FmxHandleToHWND(Handle), NULL);
::ShowWindow(hWnd, SW_HIDE);