How to customize Widgets made with GUI Designer?

[Cruz]

Hello,

I'm sorry I'm really new to this. So I designed a nice GUI with the GUI Designer and now I would like to add some functionality. For Example I have a QGroupBox that should do things when a button is pressed, like dynamicly adding and removing new Widgets to itself and also drawing polygons. But now this QGroupBox is only defined in the .ui file and I don't know how to add custom methods to it. A little help please?

Thanks
Cruz

[zgulser]

Hi,

You can use "connect" method to establish a connection between your widgets.That's how you add some functionalities to your widgets.

[spirit]

at first you need to apply created ui to a widget. it can be done using to ways
1. by multiply inheritance

#include "ui_mywidget.h"
 
class MyWidget: public QWidget, private Ui::MyWidget
{
....
public:
     MyWidget(QWidget *widget = 0);
};
....
MyWidget::MyWidget(QWdiget *widget)
: QWidget(parent)
{
     setupUi(this);
     //after that you can use all control which you added in Qt Designer, e.g.
    myGroupBox->hide();
    ...
}

#include "ui_mywidget.h"

class MyWidget: public QWidget, private Ui::MyWidget
{
....
public:
     MyWidget(QWidget *widget = 0);
};
....
MyWidget::MyWidget(QWdiget *widget)
: QWidget(parent)
{
     setupUi(this);
     //after that you can use all control which you added in Qt Designer, e.g.
    myGroupBox->hide();
    ...
}

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2. by using a class member

#include "ui_mywidget.h"
 
class MyWidget: public QWidget
{
....
public:
     MyWidget(QWidget *widget = 0);
private:
     Ui::MyWidget m_ui;
};
....
MyWidget::MyWidget(QWdiget *widget)
: QWidget(parent)
{
     m_ui.setupUi(this);
     //after that you can use all control which you added in Qt Designer, e.g.
    m_ui.myGroupBox->hide();
}

#include "ui_mywidget.h"

class MyWidget: public QWidget
{
....
public:
     MyWidget(QWidget *widget = 0);
private:
     Ui::MyWidget m_ui;
};
....
MyWidget::MyWidget(QWdiget *widget)
: QWidget(parent)
{
     m_ui.setupUi(this);
     //after that you can use all control which you added in Qt Designer, e.g.
    m_ui.myGroupBox->hide();
}

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and then make all what you need as zgulser said.

[Cruz]

Thanks spirit, but I still don't understand. Let me try to be more exact.

So I created a gui (called Editor) in desginer and it contains a button and a QGroupBox. I managed to connect the button to a slot in the Editor class. In this slot I can get a reference to thisQGroupBox like this:

Editor::slot()
{
   ui.groupBox->doSomething();
}

Editor::slot()
{
   ui.groupBox->doSomething();
}

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just like the second method you suggested. Now I would like to make a QFrame appear on this QGroupBox, so I figured:

Editor::slot()
{
   QFrame* frame = new QFrame(ui.groupBox);
   frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   frame->show();
}

Editor::slot()
{
   QFrame* frame = new QFrame(ui.groupBox);
   frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   frame->show();
}

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but it doesn't show. What I understood so far is that you put a widget "into" another one by declaring the other one as the parent in the constructor. Is that not the right way?


The painting is a different issue. groupBox should paint a line when I press the button. For this I would have to override a paint method (I need to look up the syntax yet) right? And then the Qt framework would call this paint method when it thinks it's the right time? Or triggered by me...somehow. Having a pointer to groupBox, nor the subclassing suggestion would help me with the overriding.

I ordered the book yesterday, but I'm too impatient and I want to leeearn.

Cruz

[spirit]

Thanks spirit, but I still don't understand. Let me try to be more exact.

So I created a gui (called Editor) in desginer and it contains a button and a QGroupBox. I managed to connect the button to a slot in the Editor class. In this slot I can get a reference to thisQGroupBox like this:

Editor::slot()
{
   ui.groupBox->doSomething();
}

Editor::slot()
{
   ui.groupBox->doSomething();
}

To copy to clipboard, switch view to plain text mode 

just like the second method you suggested. Now I would like to make a QFrame appear on this QGroupBox, so I figured:

Editor::slot()
{
   QFrame* frame = new QFrame(ui.groupBox);
   frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   frame->show();
}

Editor::slot()
{
   QFrame* frame = new QFrame(ui.groupBox);
   frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   frame->show();
}

To copy to clipboard, switch view to plain text mode 

but it doesn't show. What I understood so far is that you put a widget "into" another one by declaring the other one as the parent in the constructor. Is that not the right way?

do you set layout in that group-box? if yes, then try to do the following

Editor::slot()
{
   QFrame* frame = new QFrame();
   //frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   //frame->show();
   ui.groupBox->layout()->addWidget(frame);
}

Editor::slot()
{
   QFrame* frame = new QFrame();
   //frame->setGeometry(10, 10, 100, 100);
   frame->setLineWidth(20);
   //frame->show();
   ui.groupBox->layout()->addWidget(frame);
}

To copy to clipboard, switch view to plain text mode 

The painting is a different issue. groupBox should paint a line when I press the button. For this I would have to override a paint method (I need to look up the syntax yet) right? And then the Qt framework would call this paint method when it thinks it's the right time? Or triggered by me...somehow. Having a pointer to groupBox, nor the subclassing suggestion would help me with the overriding.

I ordered the book yesterday, but I'm too impatient and I want to leeearn.

Cruz

look at QPainter

[Cruz]

Thanks! Adding custom widgets works now, but painiting still doesn't. I would need to override paintEvent() and for this in Designer I would have to say "you QGroupBox, be a custom MyQGroupBox" that I created with an overriden paintEvent().

[spirit]

today I helped to solve problem with drawing on a widget which has been created in designer, maybe this topic will help you too http://www.qtcentre.org/forum/f-qt-p...ner-18014.html

[Cruz]

I see...redirect the event with an event filter. It's not a very nice solution. If I didn't use Designer, but coded my gui by hand, I wouldn't need to implement a workaround like that. Thanks a bunch anyways! You helped me a lot today.

[jpn]

I would need to override paintEvent() and for this in Designer I would have to say "you QGroupBox, be a custom MyQGroupBox" that I created with an overriden paintEvent().

See Promoting Widgets.