Discover certain QWidget gained focus in QTabWidget

RotflCopter

Hi

I am working on simple application with a few tabs, each containing another feature and I added a few QWidget based objects to QTabWidget, I want to discover that focus was gained or lost in certain tab. I wish class QWidget have a signal like focusChanged(bool isFocused) and I could very simply implement certain actions on focus gained/lost inside those QWidget based classes, but there is no such a signal so I made an workaround: each tab has its own tab number passed in constructor and QTabWidget::currentChanged is connected to a slot which checks if currently chosen tab number is equal to its own tab number. It works, but I would love to get rid of it since I have other bloat code to take care of. Are there more elegant ways to catch that focus was gained?

int tabNumber = 1;
	
someFencyTab = new SomeFencyTab(tabNumber++, &someNiceObject, this);
this->tabWidget->addTab(someFencyTab, "Fency Tab");
connect(tabWidget, &QTabWidget::currentChanged, someFencyTab, &SomeFencyTab::tabChanged);

void SomeFencyTab::tabChanged(int tab_number)
{
    bool const now_focused = tab_number == own_tab_number_;

    if (now_focused) {
        onFocusGained();
        prev_focused_ = true;
    }
    else if ((!now_focused) && prev_focused_) {
        onFocusLost();
        prev_focused_ = false;
    }
}

Reimplementing focusInEvent does not work, I tried following

class SomeFancyTab : public QWidget
{
/* ... */
  protected:
    void focusInEvent(QFocusEvent* e);
}

void SomeFancyTab::focusInEvent(QFocusEvent* e)
{
    qDebug() << "Focus gained";
}

Best regards

Pl45m4

@RotflCopter said in Discover certain QWidget gained focus in QTabWidget:

I wish class QWidget have a signal like focusChanged(bool isFocused) and I could very simply implement certain actions on focus gained/lost inside those QWidget

What about QApplication::focusWidget?

https://doc.qt.io/qt-5/qapplication.html#focusWidget

A QWidget is still a QWidget even when it's part of a tab.

RotflCopter

Hi

As usual, after posting topic I found solution:
-reimplementing QObject general event handler to see what kinds of event comes when certain action happens (switching to tab)

bool event(QEvent *event);

-reimplementing specific handlers - in my case:

void hideEvent(QHideEvent *event);
void showEvent(QShowEvent *event);

Best regards
Hope this topic will help someone in future