RE: Widget Subclassing

["Scott Aron Bloom"]

I think you need to answer the following question.  

Is your relationship between the qwidget a ISA or a HASA....

Without that question being answered, you really wont know where to
begin.

Ie Is the new qwidget a label?  Or a does it have a label.

If it is a label, and the only difference is how the frame around it is
painted...  Why not just derive from QLabel and override the necessary
paint methods for qframe/qlabel.  Since qlabel ISA qframe it shouldn't
be that hard.


Scott

-----Original Message-----
From: Andrew Medico [mailto:medico@xxxxxxxxxx] 
Sent: Friday, June 16, 2006 10:08 AM
To: qt-interest@xxxxxxxxxxxxx
Subject: Re: Widget Subclassing

Andreas Pakulat wrote:
> On 16.06.06 11:58:29, Andrew Medico wrote:
>> How would I go about subclassing a widget (say a QLabel) so that the
base class 
>> widget is a child of the subclass? (I want to draw the base class
widget inside 
>> a QFrame)
> 
> Huh?
> 
>> I know I could do this by making a custom QWidget and making a QLabel
a member 
>> object, but then I'd have to do a ton of overhead to wrap all the
QLabel's 
>> signals and slots.
> 
> Aah.
> 
>> Any thoughts? I hope it's possible and I'm just missing something
basic. 
> 
> I think you're taking the wrong approach. Could you explain a bit more
> what you're trying to accomplish? Just painting a QLabel onto a QFrame
> can be done without any subclassing, by just making the label a child
> object of the frame.

My ultimate goal is to end up with an object that can be used as a 
QLabel (it has all the same signals and slots), but to have the label 
inside a QFrame.

I know I could do something like this, but I'm hoping to avoid 
reimplementing every single slot and member function. Even if I do that,

  the object still couldn't be passed to functions that expect a QLabel*

argument.

class MyFramedLabel: public QWidget {
public:
        MyFramedLabel(QWidget* parent = NULL);
        ~MyFramedLabel();

public slots:
        void setText(const QString& text);
        void clear()

private:
        QLabel* _label;
}

MyFramedLabel::MyFramedLabel(QWidget* parent):
        QWidget(parent)
{
        QFrame* frame = new QFrame(this);
        frame->setLineWidth(2);
        frame->setFrameStyle(QFrame::Box || QFrame::Raised);
        _label = new QLabel(frame);
}

MyFramedLabel::~MyFramedLabel()
{
        delete _label;
}

MyFramedLabel::setText(const QString& text) {
        _label->setText(text);
}

void MyFramedLabel::clear()
{
        _label->clear();
}

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