键盘事件-----按下回车键则触发事件

protected:
    bool eventFilter(QObject *obj, QEvent *event);



bool frmPwd::eventFilter(QObject *obj, QEvent *event)
{
    //如果用户按下了回车键,则触发修改密码信号
    if (event->type()==QEvent::KeyPress) {
        QKeyEvent *keyEvent=static_cast<QKeyEvent *>(event);
        if (keyEvent->key()==Qt::Key_Return || keyEvent->key()==Qt::Key_Enter) {
            this->on_btnOk_clicked();
            return true;
        }
    }
    return QObject::eventFilter(obj,event);
}