Avoid application activation and focus in when clicking buttons on it - Windows API or Qt

Question

Situation: A border-less QDialog stays successfully on top of other applications.

The problem is when clicking on this always-on-top application window, the following occurs:

• The clicked always-on-top application gets activated
• The clicked always-on-top application window steals the focus of previous active/focused app

Is there a possibility that when clicking on this always-on-top inactive and unfocused application window,

• the current application does not loose activation and focus
• while user being still able to interact with the always-on-top application (hitting buttons or drop-down menus, dragging the window)?

I'm working with Qt but there's no problem about using native Windows API.

I tried the following Qt windowFlag:

• Qt::WindowDoesNotAcceptFocus but it does not work: the always-on-top application is activated, focused.
• Qt::WindowTransparentForInput, the always-on-top application is really transparent to clicks: not activated and not focused in but buttons are unfortunately not triggered when hit.

Weingartner

Answer 1

It is possible to make a window unactivable and unfocusable when clicking on it by using Windows flags (#include <qt_windows.h>). The following has to be used after the window is created and shown:

HWND winHandle = (HWND)winId();
ShowWindow(winHandle, SW_HIDE);
SetWindowLong(winHandle, GWL_EXSTYLE, GetWindowLong(winHandle, GWL_EXSTYLE)
    | WS_EX_NOACTIVATE | WS_EX_APPWINDOW);
ShowWindow(winHandle, SW_SHOW);

Weingartner

Hm, how do you do this in Qt anyway? Override winEvents? – Aryl

You can override showEvent(). For its implementation, first call the parent method then the above code. – Weingartner

Not successful :) I have already success in porting the code to PyQt using PyWin libraries, overriding showEvent(), but when I click control on this suppose-to-be-nonactive-window, my main window become inactive. Any idea? – Aryl

What about overriding showEvent() in the other window too? – Weingartner

My case is a floating QFrame containing buttons that need to be clicked. Haven't success using the above WS_EX_NOACTIVATE. Right now, I subclass pushbutton and trapping MouseButtonPress, MouseButtonRelease and MouseButtonDblClick in eventFilter. In there, I activate the main window. It's almost perfect. Sometime still a quick flashing title bar occured. But, yeah, that's the best I can do right now :) – Aryl

Does the window active when you click on its background (not on one of its button). I remember that I had to override showEvent() of menu/dropdown list of the window. – Weingartner

My background is transparent. So, users must click the button in this case. I have also override showEvent() of the buttons subclass and try to set WS_EX_NOACTIVATE there. But still the focus shifted from main window – Aryl

Try a new Qt simple project with one default window (no special effects, no transparent background, no buttons ...). See if it clicking the window does not activate the application, then trial/error different options (adding buttons, transparency, multiple windows ...). – Weingartner

Answer 2

I don't know about QDialog, I'm using just a QWidget for similar purpose (displaying a Windows 8 style notification).

Try setting:

dialog->setFocusPolicy(Qt::NoFocus);
dialog->setAttribute(Qt::WA_ShowWithoutActivating); 

maybe you'll have to set focus policy on all children.

Galloot

Thanks headsvk but it is overridden by the always on top flag: dialog->setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint); It seems that this flag is conflicting with the Qt::WA_ShowWithoutActivating attribute. – Weingartner

In fact it doesn't work at all on Windows (even without the WindowStaysOnTopHint), while on Mac there is the conflict. I tested with a MainWindow, then a QDialog and finally with a QWidget. – Weingartner

I'm also using Qt::WindowStaysOnTopHint. So I tried adding a button to my popup and when I click on it, it doesn't steal focus from my active window. How do the flags conflict? – Galloot

The conflict was on Mac (sorry for the confusion). But let's go back on Windows. The application still activates and get focus in. I've created a sample Qt GUI project then added the following code in MainWindow constructor: pastebin.com/tKB2NSHz – Weingartner

ok it doesn't work for me, my popup isn't stealing focus on show so I thought it also doesn't on click (I don't click on it, I close it on mouse enter), sorry – Galloot

however if the window which needs to stay activated is yours, you can use a simple workaround by activating it when the user clicks on the dialog – Galloot

Unfortunately it is not the case. Typically, my Qt app (to be left unactivated and unfocused) lies on top of PowerPoint. – Weingartner