As an aside, a minimal example could look like the below. Not a single declaration/statement/expression can be removed. The button aids in visualizing the problem, so it should be left in. The use of a failure trigger variable highlights exactly what condition triggers the failure: the code self-documents and you almost need no narrative to explain it. The question could be as concise as the test case below and one sentence "Why is the group box's border not visible when fail
is true?". Most likely, had you followed the minimization fully through, you'd realize yourself what the problem was - it becomes rather obvious. It's not so when MyGroupBox
is declared in another file!
The technique of putting it all into a single main.cpp
file is critical in spotting the problem: all of the code is physically next to each other, making it much easier to spot mistakes! When you minimize, usually the first things that have to go are separate files: cram it all into one file, and then relentlessly remove absolutely everything that's not directly needed in reproducing the issue.
#include <QtWidgets>
struct MyGroupBox : public QWidget {};
int main(int argc, char ** argv) {
bool fail = true;
QApplication app{argc, argv};
QWidget widget;
QVBoxLayout layout{&widget};
QGroupBox groupBox;
MyGroupBox myGroupBox;
QPushButton button;
layout.addWidget(fail ? static_cast<QWidget*>(&myGroupBox) : &groupBox);
layout.addWidget(&button);
widget.show();
return app.exec();
}
This concise style is not only for trivial test cases. In your real code, the Widget
's header and implementation could look as follows:
// Widget.h
#include <QtWidgets>
#include "MyGroupBox.h"
class Widget : public QWidget {
Q_OBJECT
QVBoxLayout layout{this};
MyGroupBox groupBox;
QPushButton button{tr("Click Me!")};
public:
explicit Widget(QWidget * parent = nullptr);
};
// Widget.cpp
#include "Widget.h"
Widget::Widget(QWidget * parent) :
QWidget{parent} {
layout.addWidget(&groupBox);
layout.addWidget(&button);
}
If you insist on shielding the interface from implementation details, don't use pointers to widgets etc., use a PIMPL.
// Widget.h
#include <QWidget>
class WidgetPrivate;
class Widget : public QWidget {
Q_OBJECT
Q_DECLARE_PRIVATE(Widget)
QScopedPointer<WidgetPrivate> const d_ptr;
public:
explicit Widget(QWidget * parent = nullptr);
};
// Widget.cpp
#include "Widget.h" // should always come first!
#include "MyGroupBox.h"
class WidgetPrivate {
Q_DECLARE_PUBLIC(Widget)
Widget * const q_ptr;
public:
QVBoxLayout layout{q_func()};
QGroupBox groupBox;
MyGroupBox myGroupBox;
QPushButton button{"Click Me!"};
WidgetPrivate(Widget * q) : q_ptr(q) {
layout.addWidget(&groupBox);
layout.addWidget(&button);
}
};
Widget::Widget(QWidget * parent) :
QWidget{parent}, d_ptr{new WidgetPrivate{this}}
{}