I need QScrollArea to contains some images

Qt Code: 
  1. TestScrollArea::TestScrollArea(QWidget *parent, Qt::WFlags flags)
  2. 	: QMainWindow(parent, flags)
  3. {
  4. 	ui.setupUi(this);
  5.  
  6. 	QWidget* widget = new QWidget;
  7. 	QVBoxLayout* layout = new QVBoxLayout( widget);
  8.  
  9. 	QImage image("D:\\data\\photo\\me\\bg2009.jpg");
  10. 	Q_ASSERT( image.isNull() == false);
  11.  
  12. 	QLabel* label1 = new QLabel;
  13. 	label1->setPixmap( QPixmap::fromImage( image));
  14. 	layout->addWidget( label1);
  15.  
  16. 	ui.scrollArea->setBackgroundRole(QPalette::Dark);
  17. 	ui.scrollArea->setWidget( widget);
  18. }
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This code was placed to the main window constructor and it worked ok (image displayed). Then I created QScrollArea child class and moved the code to its contructor:

Qt Code: 
  1. TestImageViewer::TestImageViewer(QWidget *parent)
  2. 	: QScrollArea(parent)
  3. {
  4. 	QWidget* widget = new QWidget;
  5. 	QVBoxLayout* layout = new QVBoxLayout( widget);
  6.  
  7. 	QImage image("D:\\data\\photo\\me\\bg2009.jpg");
  8. 	Q_ASSERT( image.isNull() == false);
  9.  
  10. 	QLabel* label1 = new QLabel;
  11. 	label1->setPixmap( QPixmap::fromImage( image));
  12. 	layout->addWidget( label1);
  13.  
  14. 	setBackgroundRole(QPalette::Dark);
  15. 	setWidget( widget);
  16. }
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Now I see nothing except a grey rectangle. What I'm doing wrong?