Scrollbar in scroll area not working

I have a mainwindow of size 480 x 350. The central widget of the main window is a scroll area of dimension 190 x 220. The code for this is as below -

Code:

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scrollArea = new QScrollArea(centralWidget);
        scrollArea->setObjectName(QString::fromUtf8("scrollArea"));
        scrollArea->setGeometry(QRect(210, 20, 191, 221));
        scrollArea->setWidgetResizable(true);
        scrollAreaWidgetContents = new QWidget();
 
        scrollAreaWidgetContents->setObjectName(
        QString::fromUtf8("scrollAreaWidgetContents"));
        scrollAreaWidgetContents->setGeometry(QRect(0, 0, 187, 217));
        scrollArea->setWidget(scrollAreaWidgetContents);
        MainWindow->setCentralWidget(centralWidget);

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I have a QLabel which is a child of the scrollarea. The code for this is as shown -

Code:

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QLabel* tmp = new QLabel(scrollAreaWidgetContents);
    tmp->setText("Custom Label");
    tmp->setGeometry(QRect( 300,300,60,60));
 
    scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);

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So in the application, the scrollarea must show the scroll bars & user must be able to scroll to the qlabel , which will not be in the displayable area.

But when I run it, the scrollarea does not show the scrollbars & hence its not scrollable. How do i solve this issue? Am I doing something wrong here ?

Quote:

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The central widget of the main window is a scroll area

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False, at least according to the code shown. The scroll area is in fact a child of the central widget.

Also, setGeometry() does its work relative to the parent widget, and you are setting the scrollAreaContents' geometry *before* it has a parent, for example.

All in all, I think you need to very carefully re-evaluate the parent-child hierarchy of your widgets and how it is manipulated in your code. I'm not sure if this makes a difference here, but it may be a good place to start, and certainly couldn't hurt.

I have changed my mainwindow constructor as show -

Code:

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MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    QScrollArea *scrollArea;
    QWidget *scrollAreaWidgetContents;
    scrollArea = new QScrollArea(this);
    scrollArea->setObjectName(QString::fromUtf8("scrollArea"));
    scrollArea->setGeometry(QRect(210, 20, 191, 221));
    scrollArea->setWidgetResizable(true);
    scrollAreaWidgetContents = new QWidget();
    scrollAreaWidgetContents->setObjectName(QString::fromUtf8("scrollAreaWidgetContents"));
    scrollAreaWidgetContents->setGeometry(QRect(0, 0, 187, 217));
    scrollArea->setWidget(scrollAreaWidgetContents);
    this->setCentralWidget( scrollArea );
 
    QLabel* tmp = new QLabel(scrollArea);
    tmp->setText("label");
    tmp->setGeometry(QRect(50,50,2000,2000));
	tmp->show();
 
    scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
    scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}

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Here ui is a designer form created using QtDesigner. The ui file is attached.

Attachment 5120

When i run this application, the label is not shown nor are the scrollbars visible. How should I proceed ?