Qt-> how to set ALT key active

[iuliancalin]

Can someone please explain how to set the Alt key as active permanently?
I'm trying to make an application for Ubuntu and I need to make it active.
I want to add it to the code below in the if statement:

@ void MainWindow::on_checkBoxTitleBar_toggled(bool checked)
{
settings->setValue("systemTitle", checked);
ui->buttonMinimize->setVisible(!checked);
ui->buttonClose->setVisible(!checked);

    if(!checked) {
        this->setWindowFlags(Qt::FramelessWindowHint | Qt::WindowMinimizeButtonHint );
        //here i whant the new code line for the ALT key
    } else {
        this->setWindowFlags(Qt::Window | Qt::WindowCloseButtonHint | Qt::WindowMinimizeButtonHint );
}@

I'm new to C++, just don't really understand how C++ works, but I'm trying.

[andreyc]

What do you mean "active Alt key" ?

[iuliancalin]

i mean the ALT key on my keaboard to be active even if its not pressed
i want this for using it with the mouse buttons left right buttons

i just want to try someting to see if it works

for example i have in my app a QWidget with the class centralWidget if i click it it sould know that the ALT key is pressed but in reality it is not

in my mind is looks like this:
this->setActive(Qt::Key_Alt);
but this is not c++ valid so can please someone show me an example

[andreyc]

In Qt app the developer decides how to interpret the input including the pressed keys and mouse buttons.
For each widget the app receives "the events":http://qt-project.org/doc/qt-5/qwidget.html#events for example "QWidget::keyPressEvent()":http://qt-project.org/doc/qt-5/qwidget.html#keyPressEvent or "QWidget::mousePressEvent()":http://qt-project.org/doc/qt-5/qwidget.html#mousePressEvent the QEvent parameter will contain an info about the event.

If you need to make Alt key active then

Create a flag that will tell you that user want an active-Alt.

Implement mousePressEvent for all widgets that need to use the active-Alt flag