Qt: How do I set the QComboBox width to fit the largest item?

Question

Hi,

I have a QComboBox that I fill with QStrings using:

comboBox->addItem(someString);

When I start my GUI application the width of the comboBox is always 70, even if the smallest item is much larger. How can I dynamically set the width of a QComboBox, for instance, to the largest QString within the comboBox?

Thanks!

Edit:

After some further testing I found the following soluiton:

// get the minimum width that fits the largest item.
int width = ui->sieveSizeComboBox->minimumSizeHint().width();
// set the ComboBoxe to that width.
ui->sieveSizeComboBox->setMinimumWidth(width);

Thanks

Answer 1

According to the docs the default SizeAdjustPolicy is AdjustToContentsOnFirstShow so perhaps you are showing it and then populating it?

Either populate it first before showing it or try setting the policy to QComboBox::AdjustToContents.

Edit:

BTW I'm assuming that you have the QComboBox in a suitable layout, eg. QHBoxLayout, so that the size hint/policy is actually being used.

Answer 2

Qt (4.6) online documentation has this to say about QComboBox:

enum    SizeAdjustPolicy  { AdjustToContents, AdjustToContentsOnFirstShow, AdjustToMinimumContentsLength, AdjustToMinimumContentsLengthWithIcon }

I would suggest

1. ensuring the SizeAdjustPolicy is actually being used

2. setting the enum to AdjustToContents. As you mention a .ui file I suggest doing that in Designer. Normally there shouldn't be anything fancy in your constructor at all concerning things you do in Designer.