QT Flowlayout - issue with multiline labels

Question

I have a small problem with QT layout.

I have a toolbox, and I want to populate it with some checkable buttons with a description. So I create a QWidget with a QGridLayout and put the QButton in the first cell and the QLabel in the second.

This is the most important part of the code (I removed dependancies from other irrelevant code in the app):

QWidget *createCellWidget()
{
    QToolButton *button = new QToolButton(this);
    button->setCheckable(true);
    button->setMinimumSize(57,57);
    button->setMaximumSize(57,57);

    QWidget *widget = new QWidget(this);
    QGridLayout *layout = new QGridLayout(widget);
    layout->addWidget(button, 0, 0, Qt::AlignHCenter);
    QLabel *lbl = new QLabel("my very long caption");
    lbl->setWordWrap(true);
    lbl->setAlignment(Qt::AlignCenter);

    layout->addWidget(lbl, 1, 0, Qt::AlignTop);
    widget->setMaximumWidth(80);
    widget->setMinimumWidth(80);

    return widget;
}

then I create a QGridLayout and populate it with these controls:

QWidget *itemWidget_FlowControl = new QWidget(this);
QGridLayout *_flowControl_layout = new QGridLayout(itemWidget_FlowControl);
_flowControl_layout->addWidget(createCellWidget(), 0, 0);

This works well and produces this output:

this is a nice layout. Unluckily if I enlarge the window the controls do not "flow", so I tried to replace the QGridLayout with a flowlayout (here are the source files).

Now the behavior is much better. BUT...

this is what I get. The longer captions are laid out as if they were single-lined, so the text overlaps with the button.

What can I do to make it look like before, but keeping it as a "flow layout"? Or do you know if there is any alternative in QT 5.2?

Thank you

Answer 1

What's wrong?

You are on the right track of using flowlayout.

The only problem is the internal layouts (QGridLayout in your case) of your cell widgets also stretch in response to the resize events.

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Solution

The solution is surprisingly simple:

Try to limit the stretch of the internal layout.

Within the factory function QWidget *createCellWidget():

[Option 1]

Add lbl->setMaximumWidth(60); to manually limit the stretch of label width. This makes the internal layout not stretch so "freely."

[Option 2]

Add layout->setSizeConstraint(QLayout::SetFixedSize); to restrain the internal layout stretch. By doing this, you may want to manually add some line break code (\n) to your "very long caption" in case the label width automatically decided by Qt doesn't suit your need.

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Result