在项目上使用setSizeHint.

void QListWidgetItem::setSizeHint ( const QSize & size )

这是一种正确的方法，可以告诉委托人它必须为该项目保留多少屏幕.

This is the right method for telling the delegate how much screen it must preserve for the item.

查看 http://qt-project.org/doc/qt-4.8/qlistwidgetitem .html#setSizeHint