23     bt = nullptr;  in MainWindow()
59     QListWidgetItem *bt = new QListWidgetItem(tr("BT"), &listWidget);  in MainWindow()  local
60     bt->setFont(font);  in MainWindow()
94 QString MainWindow::saveConfig(int volume, int wifi, int bt)  in saveConfig()  argument
112     out << "isBtOn = " + QString::number(bt) << endl;  in saveConfig()
169     } else if(! item->text().compare("BT")){  in on_itemClicked()
170         bt = qtBT::getInstance(this, &subTitle, &toggleBtn, isBtOn);  in on_itemClicked()
171         stack.addWidget(bt);  in on_itemClicked()
172         stack.setCurrentIndex(stack.indexOf(bt));  in on_itemClicked()
187         if(bt){  in on_returnClicked()
188             isBtOn = bt->isOn();  in on_returnClicked()
189             delete bt;  in on_returnClicked()
190             bt = nullptr;  in on_returnClicked()
205         }else if(bt){  in on_returnClicked()
206             stack.removeWidget(bt);  in on_returnClicked()
207             isBtOn = bt->isOn();  in on_returnClicked()
208             delete bt;  in on_returnClicked()
209             bt = nullptr;  in on_returnClicked()