1  void MainWindow::on_removeButton_clicked()
2  {
3    int r = ui->listWidget->currentRow();
 4   if(ui->listWidget->count() == 0)
 5       QMessageBox::information(this, "out", "list is empty");
 6   else if(r == -1)
 7       QMessageBox::information(this, "out", "select an item");
 8   else
 9       ui->listWidget->takeItem(ui->listWidget->currentRow());
10 }