How to identify when the current tab is changing in a QTabWidget?

Question

I'm using a QTabWidget and I need a way to handle the change of the current tab before it actually happens, and possibly cancel it if certain conditions are met. The QTabWidget::currentChanged signal is received after the current tab has changed, but is there a QTabWidget::currentChanging signal or another way to achieve the behavior I need?

Answer 1

In my case, I connect SIGNAL and SLOT like this:

//check if user clicked at a tab
connect(ui->tabWidget, SIGNAL(currentChanged(int)), this, SLOT(tabSelected()));

and in tabSelected() function, I check current Tab Index:

void MainWindow::tabSelected(){
    if(ui->tabWidget->currentIndex()==0){

        // Do something here when user clicked at tab1

    }
    if(ui->tabWidget->currentIndex()==3){

        // Do something here when user clicked at tab4

    }
}

Answer 2

This is how I solved it

void MainWindow::on_tabWidget_currentChanged(int index)
{
    if (lockTabs) ui->tabWidget->setCurrentIndex(lockedTab);
}

On click of a button, I set lockTabs to true and save the current tab index to lockedTab (int). No matter what tab you click it will just throw you back to the locked tab.

I do agree with the first comment that disabling tabs is the better way tho. This is my solution for disabling tabs:

void MainWindow::lockTabs(int except){
    for (int i=0; i<ui->tabWidget->count(); i++) {
        if (i!=except) ui->tabWidget->setTabEnabled(i, false);
    }
}

void MainWindow::unlockTabs() {
    for (int i=0; i<ui->tabWidget->count(); i++) {
        ui->tabWidget->setTabEnabled(i, true);
    }
}

Answer 3

In your header, declare:

QWidget *saveTab

Create a routine tabChanged have the slot for the currentChanged() signal. Then:

void pkgName::tabChanged
//"ask your question"
if "bad reply"
  // This is where you'll "set back to your old tab"
  ui->tabWidget->setCurrentWidget(savedWidget)
end if
savedWidget = ui->tabWidget-> getCurrentWidget() 
// Process