Constructor arguments of QKeyEvent ?
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Hello,
I must implement a simple virtual keyboard. It is not all clear for me how to do it. Buttons/Layout etc. is simple but how to send the keys.
Here some code examples:QWidget * w = QApplication::focusWidget(); if(!w) return; QKeyEvent e(QEvent::KeyPress, Qt::Key_X,Qt::NoModifier, "ab"); QApplication::sendEvent(w, &e); QKeyEvent e2(QEvent::KeyRelease, Qt::Key_A,Qt::NoModifier, "a"); QApplication::sendEvent(w, &e2);Unclear is the constructor of QKeyEvent. Why argument 2 AND argument 4.
Argument 2 should describe the key. For what is argument 4. I found that this string (multiple chars) will be send to the input widget and I must set here a string which is independent of argument 2. For what is argument 2 then ?
Second question is: Must I send a keyrelease for proper working of the virtual keyboard.
Any other tips for a developing a virtual keyboard are welcome, too. -
Hello,
I must implement a simple virtual keyboard. It is not all clear for me how to do it. Buttons/Layout etc. is simple but how to send the keys.
Here some code examples:QWidget * w = QApplication::focusWidget(); if(!w) return; QKeyEvent e(QEvent::KeyPress, Qt::Key_X,Qt::NoModifier, "ab"); QApplication::sendEvent(w, &e); QKeyEvent e2(QEvent::KeyRelease, Qt::Key_A,Qt::NoModifier, "a"); QApplication::sendEvent(w, &e2);Unclear is the constructor of QKeyEvent. Why argument 2 AND argument 4.
Argument 2 should describe the key. For what is argument 4. I found that this string (multiple chars) will be send to the input widget and I must set here a string which is independent of argument 2. For what is argument 2 then ?
Second question is: Must I send a keyrelease for proper working of the virtual keyboard.
Any other tips for a developing a virtual keyboard are welcome, too.Hi
I would seek inspiration in existing implementations
like
https://www.linux-apps.com/p/1132203/ -
Hi,
The QKeyEvent constructor documentation explains all the parameters.
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Hi
I would seek inspiration in existing implementations
like
https://www.linux-apps.com/p/1132203/Hello @mrjj ,
as a inspiration it is good.
They use an other concept, in the close sense it is not really a virtual keyboard. It works only with a QLineEdit (and its subclasses) and sends keystrokes never but rather manipulates the QLineEdit::text directly.In general I dont understand, why I must send a keystroke to a special widget with the following code (I in my code I look for the focused.)
QApplication::sendEvent(wiget, &event);
This works only for Qt-Apps. Why can I not send a key to the operating system and the system processes it relating to its rules ? -
Hello @mrjj ,
as a inspiration it is good.
They use an other concept, in the close sense it is not really a virtual keyboard. It works only with a QLineEdit (and its subclasses) and sends keystrokes never but rather manipulates the QLineEdit::text directly.In general I dont understand, why I must send a keystroke to a special widget with the following code (I in my code I look for the focused.)
QApplication::sendEvent(wiget, &event);
This works only for Qt-Apps. Why can I not send a key to the operating system and the system processes it relating to its rules ?@Andy314
Oh, sorry I thought it would be more clever made.
To send events to the OS, you need to use native API.Qt has support for handling the virtual keyboard
http://doc.qt.io/qt-4.8/qt-tools-inputpanel-example.html
notice the QEvent::RequestSoftwareInputPanel
I have not tested these on Desktop but Docs seems not to limit use.If you want to make a native virtual keyboard that work with ANY app, you need to dive into the native app for that.
