Dynamic Scrollarea Content

[rouge]

hi
I would like to have a scrollarea contains a dynamic count of images...

I tried to solve it like you see below. But the problem is that the scrollbar never appear...

My approach is:
I design with the QT desinger a ScrollArea (scrollArea) with default ScrollBarAsNeeded. Then I at also in the QT Designer a widget to the ScrollArea (named scrollContent).

Then in the Programm i tried:

QVBoxLayout* ScrollBoxLayout = new QVBoxLayout();
ScrollBoxLayout->setSpacing(2);
ScrollBoxLayout->setMargin(2);
ScrollBoxLayout->setAlignment(Qt::AlignTop);
ScrollBoxLayout->setSizeConstraint(QLayout::SetMinimumSize);
ui.scrollArea->setLayout(ScrollBoxLayout);

QVBoxLayout* ScrollBoxLayout = new QVBoxLayout();
ScrollBoxLayout->setSpacing(2);
ScrollBoxLayout->setMargin(2);
ScrollBoxLayout->setAlignment(Qt::AlignTop);
ScrollBoxLayout->setSizeConstraint(QLayout::SetMinimumSize);
ui.scrollArea->setLayout(ScrollBoxLayout);

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and add the images like:

for (it=sig.begin(); it!=sig.end(); it++){
  //ignore this part
  image = QImage((uchar *) it->Image()->imageData, it->Image()->width, it->Image()->height,QImage::Format_RGB888); 
  image = image.rgbSwapped(); 
 
  //add qlabel to widget in scrollarea
  QLabel *img = new QLabel(); 	
  ui.scrollArea->layout()->addWidget(img);
  img->setPixmap(QPixmap::fromImage(image));
  img->repaint();
}

for (it=sig.begin(); it!=sig.end(); it++){
  //ignore this part
  image = QImage((uchar *) it->Image()->imageData, it->Image()->width, it->Image()->height,QImage::Format_RGB888); 
  image = image.rgbSwapped(); 
  
  //add qlabel to widget in scrollarea
  QLabel *img = new QLabel(); 	
  ui.scrollArea->layout()->addWidget(img);
  img->setPixmap(QPixmap::fromImage(image));
  img->repaint();
}

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so the images appears like I wanted row by row... but no scrollbar appears if there are many QLabel objects added...

thx

[wysota]

Set the widgetResizable property of the scroll area to true.

[rouge]

hmm that is already on true...

i also set the maximum height in scrollarea but the area grows with the content...

[wysota]

This works for me:

#include <QtGui>
 
int main(int argc, char **argv){
  QApplication app(argc, argv);
  QScrollArea scroll;
  scroll.setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded); // it's default anyway
  QWidget *viewport = new QWidget;
  scroll.setWidget(viewport);
  scroll.setWidgetResizable(true);
  QVBoxLayout *l = new QVBoxLayout(viewport);
  for(int i=0;i<50;++i) {
    QPushButton *pb = new QPushButton(QString::number(i+1));
    l->addWidget(pb);
  }
  scroll.show();
  return app.exec();
}

#include <QtGui>

int main(int argc, char **argv){
  QApplication app(argc, argv);
  QScrollArea scroll;
  scroll.setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded); // it's default anyway
  QWidget *viewport = new QWidget;
  scroll.setWidget(viewport);
  scroll.setWidgetResizable(true);
  QVBoxLayout *l = new QVBoxLayout(viewport);
  for(int i=0;i<50;++i) {
    QPushButton *pb = new QPushButton(QString::number(i+1));
    l->addWidget(pb);
  }
  scroll.show();
  return app.exec();
}

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[rouge]

yes this works...

but in my case I have a mainwindow and on that there is the scrollarea... and I try to add at runtime...
and I think thats my problem...

or is there something other wrong??'

---

Added after 26 minutes:

wow now it works!

the problem was that the scrollarea must have a layout too!!!

thx

[wysota]

the problem was that the scrollarea must have a layout too!!!

The problem is the code you provided states the scroll area has a layout. You probably mean the main window needs a layout.

[rouge]

The problem is the code you provided states the scroll area has a layout. You probably mean the main window needs a layout.

yes sure I mean the main window