QCombobox写＆＃34; HELLO＆＃34;按退格键时

Question

当我按下Qcombobox-＆gt; linEdit（），键Backpace并清除所有文本时，我想要拦截信号。 我在网上看过，我写了这段代码，但它不起作用。似乎没有调用keypressevent函数..一些提示???

 MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent), ui(new Ui::MainWindow)
    {
        ui->setupUi(this);
        ui->comboBox->addItem("11");
        ui->comboBox->addItem("21");
        ui->comboBox->addItem("32");
        ui->comboBox->addItem("41");
        ui->comboBox->addItem("54");
    }

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
  if (obj == ui->comboBox) {
     if (event->type() == QEvent::KeyPress) {
         QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
         qDebug()<<"Ciao";
         if (keyEvent->key() == Qt::Key_Backspace)
         {
             ui->comboBox->clearEditText();
             return true;
         }
  }
     // pass the event on to the parent class
     return QMainWindow::eventFilter(obj, event);
}
}
MainWindow::~MainWindow()
{
    delete ui;
}

Answer 1

添加ui->comboBox->installEventFilter(this);