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

问题

I have a QComboBox that I fill with QString using:

comboBox->addItem(someString);

When I start my GUI application the width of the QComboBox 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?

Edit:

After some further testing I found the following solution:

// 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);

回答1:

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

enum    SizeAdjustPolicy  { AdjustToContents, AdjustToContentsOnFirstShow, AdjustToMinimumContentsLength, AdjustToMinimumContentsLengthWithIcon }

I would suggest

ensuring the SizeAdjustPolicy is actually being used
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.

回答2:

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.

回答3:

I was searching for a solution to only change the size of the dropdown menu of the combobox to fit the largest text without changing the size of the combobox itself.

Your suggestion (@Linoliumz) did help me find the solution. Here it is : Suppose you have a combobox called cb:

C++:

width = cb->minimumSizeHint().width()
cb->view().setMinimumWidth(width)

PyQT :

width = cb.minimumSizeHint().width()
cb.view().setMinimumWidth(width)

来源：https://stackoverflow.com/questions/3151798/how-do-i-set-the-qcombobox-width-to-fit-the-largest-item

标签

c++

user-interface

qcombobox