How to keep widget's size to one which is just sufficiennt to display contents?

[yogeshm02]

Hi

Here is the constructor for main widget:

GMessenger::GMessenger() : QWidget(0, Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint){
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
    m_pLayout = new QVBoxLayout();
    setLayout(m_pLayout);
}

GMessenger::GMessenger() : QWidget(0, Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint){
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
    m_pLayout = new QVBoxLayout();
    setLayout(m_pLayout);
}

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Here is the constructor for child widget:

GMessenger::ProgressJobNotifier::ProgressJobNotifier(const QString &title) : QFrame(0){
    setFrameStyle(QFrame::StyledPanel | QFrame::Raised);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
 
    ...
 
    setLayout(m_pVLayout);
}

GMessenger::ProgressJobNotifier::ProgressJobNotifier(const QString &title) : QFrame(0){
    setFrameStyle(QFrame::StyledPanel | QFrame::Raised);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);

    ...

    setLayout(m_pVLayout);
}

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QFrame derived child widget increases/decreases its size when a child widget is added to it, while QWidget derived top level widget increases its size when a child widget is added but not decreases its size when a child widget is removed (Which is what i want). So help please!

[jacek]

QWidget derived top level widget increases its size when a child widget is added but not decreases its size when a child widget is removed (Which is what i want).

Are you sure? Judging from the title of your post, you want the opposite.

QWidget::adjustSize()

[wysota]

You might be looking for QLayout::setSizeConstraint(QLayout::SetFixedSize).

[yogeshm02]

QLayout::setSizeConstraint(QLayout::SetFixedSize) is working
But, it seems like I'll have to invest more time understanding behaviour of QLayout::setSizeConstraint(QLayout::SetFixedSize) and setSizePolicy(QSizePolicy::Policy, QSizePolicy::Policy)

Bye

[wysota]

The difference is simple - sizepolicy constrains the size of a widget when that widget is in a layout (so it doesn't work for top level widgets) and setSizeConstraint controls the parent of the layout (or rather the layout itself).