SIGSEGV while adding to QListWidget

Question

I have a problem with adding an element to a QListWidget. I have build some frame with QtDesigner and then, I want to add some elements to a list in code. Even when I write:

QListWidgetItem* i = new QListWidgetItem("text");
Q_ASSERT(stepsList);
qDebug() << "before";
stepsList->addItem(i);
qDebug() << "after";

It prints only "before" and crashes with SIGSEGV. Additionaly, I managed to get such error message with this:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff6f2a4a4 in QListWidget::count() const ()
from /usr/lib/x86_64-linux-gnu/libQtGui.so.4

What is the reason?

Answer 1

Well, acceptation is needed so I'll write what was wrong:

I needed to call setupUi() first, in order to initialize the stepsList as @Timo Geusch wrote.

Solved.