QTabWidget setCurrentIndex无法按预期工作

Question

I am trying to change the view to the main tab when a user clicks on the second tab of QTabWidget if a certain condition is met, but when I call setCurrentIndex() inside of on_tabWidget_tabBarClicked() , the view stays on the current tab. Please see the code below.

If I call setCurrentIndex() outside of on_tabWidget_tabBarClicked() , then it works.

void MainWindow::on_tabWidget_tabBarClicked(int index)
{
    if (index == 1)
    {
        Error("Empty, back to main");
        ui->tabWidget->setCurrentIndex(0);
    }
}

Answer 1

The problem in your case is that when the signal is triggered even your mouse is on the QTabWidget so even if you change the tab with setCurrentIndex(0) then the mouse event will change it back to 1. In this case the logic is change it a moment later and for this a QTimer is used:

void MainWindow::on_tabWidget_tabBarClicked(int index)
{
   if(index==1)
   {
       Error("Empty, back to main");
       QTimer::singleShot(100, [this](){ ui->tabWidget->setCurrentIndex(0); });
   }
}

Answer 2

Using the slot on_tabWidget_currentChanged instead of tabBarClicked would also work correctly since this is called once the tab change is complete. That would avoid the need to call the asynchronous QTimer.

void MainWindow::on_tabWidget_currentChanged(int index)
{
    if (index == 1)
    {
        Error("Empty, back to main");
        ui->tabWidget->setCurrentIndex(0);
    }
}