[solved] How to catch mouse click event on titlebar area of QMainWindow?

[yunxiaodong]

Because the titlebar belongs to the OS,so I cant catch mouse click event on titlebar area of QMainWindow.
How to catch it?

[task_struct]

AFAIK, it is impossible or at least its impossible on Linux. Titlebar(window decoration) is separate program. Widgets inside doesnt know anything about decoration.

[cincirin]

I don't know with Qt framework, but on windows you can catch the "WM_NCHITTEST":http://msdn.microsoft.com/en-us/library/ms645618(v=vs.85).aspx message, and check if HTCAPTION is the return value of DefWindowProc.

[yunxiaodong]

In Qt Assistant:

The QDecoration class is a base class for window decorations in Qt for Embedded Linux
Note that this class is non-portable and only available in Qt for Embedded Linux.
Reimplement the regionClicked() and regionDoubleClicked() functions to respond to mouse clicks

it seemed like possible in Embedded linux only

[andre]

No, in Embedded linux. That is: none desktop, where Qt plays its own window manager. I doubt that is the use case that you have.

[giesbert]

Hi,

you have to deal with OS messages for that. On windows, you can use QWidget::winEvent() to catch those events, for linux tghere are similar message handlers. I am sure also for mac.
The only thing you additionally need is which messages to catch...

[yunxiaodong]

Gerolf and cincirin, finally, As you suggested problems have been solved.

@bool gwMainWindow::winEvent ( MSG * msg, long * result )
{
if (msg->message == WM_NCLBUTTONDOWN)
{
//here can catch the leftmousedown event on titlebar
}

return false;
}@

[giesbert]

[quote author="yunxiaodong" date="1314326449"]Gerolf and cincirin, finally, As you suggested problems have been solved.

@bool gwMainWindow::winEvent ( MSG * msg, long * result )
{
if (msg->message == WM_NCLBUTTONDOWN)
{
//here can catch the leftmousedown event on titlebar
}

return false;
}@[/quote]

But, if you do some platform independant stuff, you need to do more :-)

[cincirin]

[quote author="yunxiaodong" date="1314326449"]
@bool gwMainWindow::winEvent ( MSG * msg, long * result )
{
if (msg->message == WM_NCLBUTTONDOWN)
{
//here can catch the leftmousedown event on titlebar
}

return false;
}@[/quote]
With WM_NCLBUTTONDOWN notify message you're not sure click on title bar. Indeed title bar is non client area, but a window, outside the titlebar has other non-client area.

[yunxiaodong]

Oh,I see. Thanks for the advice.

[yunxiaodong]

and it should be like this

@bool gwMainWindow::winEvent ( MSG * msg, long * result )
{
if (msg->message == WM_NCLBUTTONDOWN)
{
int nHittest = (INT) msg->wParam;
if (nHittest == HTCAPTION)
{
//here catch the lbuttondown event only on titlebar
}
}
}@