Make an example of QT in MDI

[avis_phoenix]

in the examples of QT is one is called "Paint and Plug", wanted to pass it to MDI, then I made a class of QScrollArea type but don't show me that I specify to him in setWidget, then I do not know in which it mistakes to me or How I can pass it to MDI?

[Big Duck]

It'd be helpfull if you could post some code to let us understand better what your trying to do.

here's the code from: http://doc.trolltech.com/4.1/qscrollarea.html

QLabel *imageLabel = new QLabel;
    QImage image("happyguy.png");
    imageLabel->setPixmap(QPixmap::fromImage(image));
 
    scrollArea = new QScrollArea;
    scrollArea->setBackgroundRole(QPalette::Dark);
    scrollArea->setWidget(imageLabel);

QLabel *imageLabel = new QLabel;
    QImage image("happyguy.png");
    imageLabel->setPixmap(QPixmap::fromImage(image));

    scrollArea = new QScrollArea;
    scrollArea->setBackgroundRole(QPalette::Dark);
    scrollArea->setWidget(imageLabel);

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Presumably you can add a widget to the mdi. Perhaps you need to pass some p ointers between widgets and the MDI.

[avis_phoenix]

well i make a two class

class Win: public QScrollArea
{
   ...
}
class paintArea: public QWidget
{
  ...
  private:
       void paintEvent(QEvent *event);
       QImage Paper;
  ...
}

class Win: public QScrollArea
{
   ...
}
class paintArea: public QWidget
{
  ...
  private:
       void paintEvent(QEvent *event);
       QImage Paper;
  ...
}

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in the constructor of win class:

Win::Win(QWidget *parent): QScrollArea(parent)
{
  paintArea *paper = new paintArea;
  setBackgroundRole(QPalette::Dark);
  setWidget(paper);
  ...
}

Win::Win(QWidget *parent): QScrollArea(parent)
{
  paintArea *paper = new paintArea;
  setBackgroundRole(QPalette::Dark);
  setWidget(paper);
  ...
}

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in the constructor of paintarea class i define a QImage name's Paper. in the function apintEvent of paintarea draw the image Paper.

When i create a mdichild with win class show a window with Dark Background, but never show the paint area,What is my mistake?

[fullmetalcoder]

When i create a mdichild with win class show a window with Dark Background, but never show the paint area,

What you're saying doesn't make sense! If you see a window with dark background then it is what you call a paint area...

[Big Duck]

in the MDI example from : qt4 docs

MdiChild *child = createMdiChild();
        child->newFile();
        child->show();

MdiChild *child = createMdiChild();
        child->newFile();
        child->show();

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I am a QT beginner, but how I use the documentation examples is to copy code and delete all the code that I dont need. This makes me understand what code is needed to make something work.

I dont think you use PaintEvent to draw the image. Sorry I cant help more...

[fullmetalcoder]

in the constructor of win class:

Win::Win(QWidget *parent): QScrollArea(parent)
{
  paintArea *paper = new paintArea;
  setBackgroundRole(QPalette::Dark);
  setWidget(paper);
  ...
}

Win::Win(QWidget *parent): QScrollArea(parent)
{
  paintArea *paper = new paintArea;
  setBackgroundRole(QPalette::Dark);
  setWidget(paper);
  ...
}

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What is my mistake?

1) Using setWidget() is wrong... your paint area becomes the only child of the scrollarea so there can't be any MDI...
2) If nothing appear except a background there can be two reasons : paintArea is not explicitely shown or its paintEvent() is not working properly...
3) If MDI is what you trully want then why are you using QScrollArea and not QWorkspace???
4) Hope this helps...

[avis_phoenix]

But the mdi child is win class not a paintarea, in another class use a QWorkspace for make mdi this window and mdichild a win class.

[avis_phoenix]

well i found mi error, was a stupid error, only change that:

Win::Win(QWidget *parent): QScrollArea(parent)
{
    paintArea *paper = new paintArea;
    setBackgroundRole(QPalette::Dark);
    setWidget(paper);
    paper->show();
    ...
}

Win::Win(QWidget *parent): QScrollArea(parent)
{
    paintArea *paper = new paintArea;
    setBackgroundRole(QPalette::Dark);
    setWidget(paper);
    paper->show();
    ...
}

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that's all

[jpn]

Hmm, there's most likely something wrong with your widgets' parent-child relationships (QScrollArea should reparent the "paint area" widget correctly during setWidget(), though). You shouldn't have to explicitly call show() in a situation like yours. Which exact version of Qt is this?

[avis_phoenix]

Well, but without show() don't show the widget in QScrollArea, my version of QT is 4.1.2