How to enable a dynamic whatsthis-string in Qt using QWhatsThis? - c++

Question

In order to have a dynamic what's this string for a widget in Qt the following almost works (following the documentation http://doc.qt.io/qt-5/qtwidgets-widgets-tooltips-example.html ):
class MyEdit : public QLineEdit {
Q_OBJECT
public:
bool event(QEvent*e) {
if (e && e->type() == QEvent::WhatsThis) {
if (QHelpEvent *helpEvent = reinterpret_cast<QHelpEvent *>(e)) {
QWhatsThis::showText(helpEvent->globalPos(), "My text...");
return true;
}
}
return QLineEdit::event(e);
}
};
Activating what's this for the window and clicking on the widget shows "My text" (the actual text is more complicated).
Issues:
Activating what's this for the window and hovering over this widget shows a dead cursor
Shift-F1 does not work inside the widget.
The first issue could be worked around by calling setWhatsThis("Dummy text"); with a non-empty string, but it feels like a hack and Shift-F1 in this widget shows "Dummy text".
Is there a non-hack way of handling it - especially so that it will not be broken by updates?

Answer 1

In case someone else stumbles on this issue the following seems to handle the Shift-F1:
class MyEdit : public QLineEdit {
Q_OBJECT
public:
bool event(QEvent*e) {
if (e && e->type() == QEvent::WhatsThis) {
if (QHelpEvent *helpEvent = reinterpret_cast<QHelpEvent *>(e)) {
QWhatsThis::showText(helpEvent->globalPos(), "My text...");
return true;
}
}
if (e && e->type() == QEvent::KeyPress) {
if (QKeyEvent *qk = reinterpret_cast<QKeyEvent *>(e)) {
if (qk->key() == Qt::Key_F1 && (qk->modifiers()&Qt::ShiftModifier)) {
QWhatsThis::showText(w.mapToGlobal(w.inputMethodQuery(Qt::ImCursorRectangle).toRect().center()), "My text...");
qk->accept();
return true;
}
}
}
return QLineEdit::event(e);
}
};
and combined with calling setWhatsThis("Dummy text"); also the hovering-part. However, it is not an elegant solution.