QScrollArea margins

[munna]

Hi,

I have a scroll area in which i need to palce a widget with some margin so that it looks as if it is placed at the center of the area.

Doing this was very simple using Qt3 but I am not able to find a way to do this using Qt4.

Can someone please help?

Thanks a lot.

[high_flyer]

did you try QScrollArea::ensureVisible ( int x, int y, int xmargin = 50, int ymargin = 50 )?

[munna]

did you try QScrollArea::ensureVisible ( int x, int y, int xmargin = 50, int ymargin = 50 )?

I thought that was to bring the point (x,y) int the scroll area appear in the viewport with the given margins.

Am I wrong?

[high_flyer]

you are right - but isn't it exactly what you want?

[munna]

No, I dont want that.

In Qt3, if I use :

scrollview->addChild(widget,10,10);

scrollview->addChild(widget,10,10);

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The widget will appear from the point (10,10), which means I will have some top and left margin.

Using resizeContents() I can get the right and the bottom margins also.

This is not so simple in Qt4.

[wysota]

You can add a layout to the area and add the widget to the layout. You can then set margins used by that layout and it should do what you want.

[sunil.thaha]

From the Book: Practical Qt
try adding the line:

scrollView->setResizePolicy( QScrollView::AutoOneFit );

scrollView->setResizePolicy( QScrollView::AutoOneFit );

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[munna]

I tried

QVBoxLayout *mainLayout  = new QVBoxLayout(scrollarea);
mainLayout->addWidget(widget);
scrollarea->setLayout(layout)
scrollarea->setWidget(widget)

QVBoxLayout *mainLayout  = new QVBoxLayout(scrollarea);
mainLayout->addWidget(widget);
scrollarea->setLayout(layout)
scrollarea->setWidget(widget)

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but is not working. I am sure this is not what you meant. Can you please explain ?

Thanks.

[wysota]

It should probably be

QVBoxLayout *mainLayout  = new QVBoxLayout(scrollarea->viewport());
mainLayout->addWidget(widget);
scrollarea->setLayout(layout);

QVBoxLayout *mainLayout  = new QVBoxLayout(scrollarea->viewport());
mainLayout->addWidget(widget);
scrollarea->setLayout(layout);

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If this doesn't help try:

QWidget *wgt = new QWidget();
QVBoxLayout *mainLayout  = new QVBoxLayout();
mainLayout->addWidget(widget);
wgt->setLayout(mainLayout);
scrollarea->setWidget(wgt);

QWidget *wgt = new QWidget();
QVBoxLayout *mainLayout  = new QVBoxLayout();
mainLayout->addWidget(widget);
wgt->setLayout(mainLayout);
scrollarea->setWidget(wgt);

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[munna]

No. Its not working.

I think I have to use some round about way to do this.

[wysota]

But what do you mean "it is not working"? Could you elaborate? Did you set the margin for that layout?

[munna]

Here is my code

previewArea = new PreviewArea(this);
previewArea->setWidgetResizable(true);
 
previewWidget = new PreviewWidget(previewArea);
 
QVBoxLayout *pLay = new QVBoxLayout(previewArea->viewport());
pLay->setMargin(10);
pLay->addWidget(previewWidget);
 
previewArea->setLayout(pLay);	
previewArea->setWidget(previewWidget);

previewArea = new PreviewArea(this);
previewArea->setWidgetResizable(true);

previewWidget = new PreviewWidget(previewArea);

QVBoxLayout *pLay = new QVBoxLayout(previewArea->viewport());
pLay->setMargin(10);
pLay->addWidget(previewWidget);

previewArea->setLayout(pLay);	
previewArea->setWidget(previewWidget);

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With the above code, when I close the window that contains the area, my application crashes. I think the crash has some thing to do with QVBoxLayout *pLay = new QVBoxLayout(previewArea->viewport());

The next option

previewArea = new PreviewArea(this);
previewArea->setWidgetResizable(true);
previewWidget = new PreviewWidget(onlyCurr,cd,previewArea);
 
QVBoxLayout *pLay = new QVBoxLayout();
pLay->setMargin(10);
pLay->addWidget(previewWidget);
previewArea->setLayout(pLay);
previewArea->setWidget(previewWidget);

previewArea = new PreviewArea(this);
previewArea->setWidgetResizable(true);
previewWidget = new PreviewWidget(onlyCurr,cd,previewArea);

QVBoxLayout *pLay = new QVBoxLayout();
pLay->setMargin(10);
pLay->addWidget(previewWidget);
previewArea->setLayout(pLay);
previewArea->setWidget(previewWidget);

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The above code is also not working. But this is not crashing the application.

Thanks for your help.