void MainWindow::convert() { emit this->started(); QtConcurrent::run([&]{ QElapsedTimer t; t.start(); Book currentBook; for(int i = 0; i < ui->listWidget->count(); ++i) { currentBook.setSource(ui->listWidget->item(i)->text()); currentBook.convert(); emit completed((i*100)/ui->listWidget->count()); } qDebug()<<t.nsecsElapsed(); emit this->finished(); }); }