qkeyevent

问题 I am beginner to qt. I was working on calculator gui application, I have already defined slots like numPressed() when any of the number pushbutton is pressed on the calculator that will be displayed on the lineEdit. void Calculator::numPressed(){ QPushButton *button = (QPushButton *)sender(); QString buttonValue = button->text(); Qstring display = ui->lineEdit->text(); Qdouble ProcessedValue = previousValue + buttonValue.toDouble(); . . . ui->lineEdit->setText(QString::number(ProcessedValue))

问题 I am beginner to qt. I was working on calculator gui application, I have already defined slots like numPressed() when any of the number pushbutton is pressed on the calculator that will be displayed on the lineEdit. void Calculator::numPressed(){ QPushButton *button = (QPushButton *)sender(); QString buttonValue = button->text(); Qstring display = ui->lineEdit->text(); Qdouble ProcessedValue = previousValue + buttonValue.toDouble(); . . . ui->lineEdit->setText(QString::number(ProcessedValue))

问题 I am beginner to qt. I was working on calculator gui application, I have already defined slots like numPressed() when any of the number pushbutton is pressed on the calculator that will be displayed on the lineEdit. void Calculator::numPressed(){ QPushButton *button = (QPushButton *)sender(); QString buttonValue = button->text(); Qstring display = ui->lineEdit->text(); Qdouble ProcessedValue = previousValue + buttonValue.toDouble(); . . . ui->lineEdit->setText(QString::number(ProcessedValue))

问题 I have a qml Window with an Item which has Keys.onPressed { } And I have a c++ class which has protected: void keyPressEvent(QKeyEvent *event); What needs to go inside the Keys.onPressed? I have tried myclass.keyPressEvent(event) and I have tried a public Q_INVOKABLE function (handleKeyPress) in my c++ class with parameter (QKeyEvent * event) from which I wanted to call the keyPressEvent . At runtime the former gives "TypeError: Property 'keyPressEvent' of object myclass is not a function"

问题 QKeyEvent has a function called nativeScanCode What is a scan code and how does it relate to a key code and/or modifiers? What is the intended use of this function and can it be used instead of the nativeVirtualKey function? 来源： https://stackoverflow.com/questions/64864189/how-to-use-qkeyeventnativescancode

问题 My child widget does not get keyPressEvents, while if I put the same widget as top level window, it does. I try to set it get focus, but it has no effect on this. Code is below, showing what I try to get to work. #include <QApplication> #include <QKeyEvent> #include <QLCDNumber> #include <QLabel> #include <QVBoxLayout> class DigitSummer: public QLCDNumber { Q_OBJECT public: DigitSummer(QWidget *parent = nullptr) : QLCDNumber(parent) { } protected: void keyPressEvent(QKeyEvent *event) override

问题 My child widget does not get keyPressEvents, while if I put the same widget as top level window, it does. I try to set it get focus, but it has no effect on this. Code is below, showing what I try to get to work. #include <QApplication> #include <QKeyEvent> #include <QLCDNumber> #include <QLabel> #include <QVBoxLayout> class DigitSummer: public QLCDNumber { Q_OBJECT public: DigitSummer(QWidget *parent = nullptr) : QLCDNumber(parent) { } protected: void keyPressEvent(QKeyEvent *event) override

问题 I've disabled X button in Qt from my dialog using this line: myDialog->setWindowFlags(Qt::Dialog | Qt::Desktop) but I couldn't detect Alt + F4 using this code: void myClass::keyPressEvent(QKeyEvent *e) { if ((e->key()==Qt::Key_F4) && (e->modifiers()==Qt::AltModifier)) doSomething(); } what should I do to detect Alt + F4 or disable it in Qt? 回答1: Pressing Alt+F4 results in a close event being sent to your top level window. In your window class, you can override closeEvent() to ignore it and

问题 I want to handle key events of the arrow keys in my application. I have already read that for doing so the focus must be disabled. I follow this method: PyQt not recognizing arrow keys. Indeed, when calling self.setChildrenFocusPolicy(QtCore.Qt.NoFocus) (as defined in the linked thread and in my source code below) within MyApp.__init__ , hitting an arrow key raises a key event. However, I do not want to keep the focus disabled during the entire runtime of the application but only upon

问题 I am using QKeyEvent to get the Shift+numeric key, but it return me the ascii for "!" instead of "1" so my problem is, is there any method or techniques to get the actual numeric value's ascii instead of ascii of "!" (special character). I also followed this thread: Get key char (value) from keycode with shift modifier but it does not seems to help me to get rid from this problem. Thanks in advance. 回答1: I believe at least as of version 4.8 there is no standard method to get the numeric ascii