Custom widget in Qt Designer with pre-existing layout in frame - c++

Question

A project uses custom frame widget that implements a kind of "cover" that hides widgets (think of it as of security cover that prevents pressing buttons).This is a required visual design. Qt version is 4.6
#ifndef CQFRAME_H
#define CQFRAME_H
#include <QFrame>
#include <QtDesigner/QDesignerExportWidget>
//! [0] //! [1]
class CQFrame : public QFrame
// our agreement about "custom" widgets is to start them with CQ
{
Q_OBJECT
Q_ENUMS(FrameColorStyle)
Q_PROPERTY(FrameColorStyle colorStyle READ getColorStyle WRITE setColorStyle)
Q_PROPERTY(bool border READ border WRITE setBorder)
//! [0]
private:
bool curCover;
QFrame *frameCover;
public:
enum FrameColorStyle {fcDark, fcLight, fcTransparent, fcSystemDefault, fcRed, fcGreen, fcBlue};
CQFrame(QWidget *parent = 0);
void setCoverPropertie();
void setCover(bool state);
protected:
void resizeEvent(QResizeEvent *event);
FrameColorStyle m_colorStyle;
QString pstylebord;
bool m_border;
//! [2]
};
//! [1] //! [2]
#endif
I omitted getters and setters that are irrelevant to the problem. Here is implementation:
void CQFrame::setCoverPropertie()
{
QString str, strAlpha, gradient1, gradient2;
strAlpha.setNum(200);
gradient1 = "rgba("+str.setNum(cwDisableColor.red())+", "
+str.setNum(cwDisableColor.green())
+", "+str.setNum(cwDisableColor.blue())
+" ," +strAlpha+ " )";
gradient2 = "rgba("+str.setNum(cwLbColor.red())+", "
+str.setNum(cwLbColor.green())+", "
+str.setNum(cwLbColor.blue())+" ," +strAlpha+ " )";
QStackedLayout *stackedLayout = new QStackedLayout(this);
frameCover = new QFrame(this);
frameCover->setGeometry(rect());
frameCover->setStyleSheet("QFrame{border:5px solid "+strLbColor+"; "
"border-radius: 10px; background-color: "
"qlineargradient(x1: 0, y1: 0, x2: 0, y2: 0.5, stop: 0 "
+gradient1+" , stop: 1 "+gradient2+"); }");
stackedLayout->addWidget(frameCover);
stackedLayout->setStackingMode(QStackedLayout::StackAll);
}
void CQFrame::setCover(bool state)
{
frameCover->setVisible(curCover = state);
}
void CQFrame::resizeEvent(QResizeEvent *event)
{
if (curCover)
frameCover->setGeometry(rect());
}
The design isn't mine, I was asked to fix strange visual glitches it experiences. This "frame" is used in Qt designer as one of widgets. After a while suddenly everything resizes, which prompted question "what is wrong with this code". Qt fires warning about attempt to add layout while one already exist: I suppose that may cause a problem, because a frame must have only one layout at time? Code generated by Qt Creator looks something like
void setupUi(CQFrame *CQWnd1T2SeparateONForm)
{
if (CQWnd1T2SeparateONForm->objectName().isEmpty())
CQWnd1T2SeparateONForm->setObjectName(QString::fromUtf8("CQWnd1T2SeparateONForm"));
CQWnd1T2SeparateONForm->resize(735, 241);
QSizePolicy sizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
sizePolicy.setHorizontalStretch(0);
sizePolicy.setVerticalStretch(0);
sizePolicy.setHeightForWidth(CQWnd1T2SeparateONForm->sizePolicy().hasHeightForWidth());
CQWnd1T2SeparateONForm->setSizePolicy(sizePolicy);
gridLayout = new QGridLayout(CQWnd1T2SeparateONForm); // warning here
}
There is similar problem with standard QMainWindow which always got own "special" layout, which Qt Creator solves automatically, by adding a central widget to the layout and everything else is added to that widget. What I don't know that is how to simulate same behavior with a custom widget with Qt Creator plugin.
Or what alternative design for CQFrame can be used. CQFrame reused in dozen project, in about 30+ panels, so reuse of code for them all is a strict requirement.
Current plugin is very basic:
class QDESIGNER_WIDGET_EXPORT CQFramePlugin : public QObject,
public QDesignerCustomWidgetInterface
{
Q_OBJECT
Q_INTERFACES(QDesignerCustomWidgetInterface)
public:
CQFramePlugin(QObject *parent = 0);
bool isContainer() const;
bool isInitialized() const;
QIcon icon() const;
QString domXml() const;
QString group() const;
QString includeFile() const;
QString name() const;
QString toolTip() const;
QString whatsThis() const;
QWidget *createWidget(QWidget *parent);
void initialize(QDesignerFormEditorInterface *core);
private:
bool initialized;
};
.cpp for it:
#include "cqframe.h"
#include "cqframeplugin.h"
#include <QtPlugin>
CQFramePlugin::CQFramePlugin(QObject *parent)
: QObject(parent)
{
initialized = false;
}
void CQFramePlugin::initialize(QDesignerFormEditorInterface * /* core */)
{
if (initialized)
return;
initialized = true;
}
bool CQFramePlugin::isInitialized() const
{
return initialized;
}
QWidget *CQFramePlugin::createWidget(QWidget *parent)
{
return new CQFrame(parent);
}
QString CQFramePlugin::name() const
{
return "CQFrame";
}
QString CQFramePlugin::group() const
{
return "CustomWidgets";
}
QIcon CQFramePlugin::icon() const
{
return QIcon(":/Resources/frame_icon.png");
}
QString CQFramePlugin::toolTip() const
{
return "";
}
QString CQFramePlugin::whatsThis() const
{
return "";
}
bool CQFramePlugin::isContainer() const
{
return true;
}
QString CQFramePlugin::domXml() const
{
return "<ui language=\"c++\">\n"
" <widget class=\"CQFrame\" name=\"Frame\">\n"
" <property name=\"geometry\">\n"
" <rect>\n"
" <x>0</x>\n"
" <y>0</y>\n"
" <width>120</width>\n"
" <height>80</height>\n"
" </rect>\n"
" </property>\n"
" </widget>\n"
"</ui>";
}
QString CQFramePlugin::includeFile() const
{
return "cqframe.h";
}

Answer 1

So I haven't worked with QT yet, but I'm going to gie it a try. First thing, I think, is that you should use the QStackedLayout to cover the widgets (source and QT manual). But you need to have a single stack.
So the stack should be a private member of CQFrame. E.g.
class CQFrame : public QFrame
{
[...]
private:
QWidget* _frame; // Frame to cover.
QFrame* _frameCover;
QStackedLayout* _stackedLayout;
[...]
And probably:
CQFrame::~CQFrame()
{
delete _stackedLayout;
delete _frameCover;
}
Then you could already initialize everything in the constructor
CQFrame::CQFrame(QWidget* parent = 0, QWidget* frame)
: QFrame(parent)
, _frame(frame)
, _frameCover(new QFrame(this))
, _stackedLayout(new QStackedLayout(this))
{
_frameCover->setGeometry(rect());
[...]
_stackedLayout->addWidget(frame);
_stackedLayout->addWidget(frameCover);
//default:_stackedLayout->setStackingMode(QStackedLayout::StackOne);
}
You could then switch between widgets in the stack using
void CQFrame::SetCover(bool state)
{
if (state) _stackedLayout->setCurrentWidget(_frameCover);
else _stackedLayout->setCurrentWidget(_frame);
}
Maybe this helps you.
edit2:
I removed this code, as it was incorrect, both in coding format, as in idea
So I checked the QT sources QStackedLayout.cpp and QLayout and it seems a QWidget can have only one layout. If you add another layout, you get an error.
Furthermore, a QStackedLayout is a QLayout, is QObject. That could indicate it is automatically removed?
I'm not sure of the cover is implemented in QT as it should. It seems like you have a QWidget you want to cover, on top of which you put a QStackedLayout that is not used as designed i.e. switching stack objects, on top of which you put a new QWidget that is made visible or not.
And maybe that bottom QWidget is already in a (stacked)layout, etc.