Connect a QListWidget selection with another QListWidget

Question

edit
SOLVED, i just forgot to initialize found_users

I have two QListWidget into a single window. The one on the left is the list of all the users of my database.
The one on the right displays a subset of accounts related to a query result.
I want the selection on the right to be reflected on the left.
For example if i have on the left

usr1
usr2
usr3
usr4

and I select "usr3" on the right list, it should be trigger the selection of "usr3" on the left.

Here's the code:
.h

class win_admin : public QWidget{  
    Q_OBJECT  
private:  
    QListWidget* all_users;  
    QListWidget* found_users;  
public:  
[...]  
public slots:  
    void send_to_main_list();  
[...]  
}  

.cpp

connect (found_users, SIGNAL(itemSelectionChanged()), this, SLOT(send_to_main_list()));
[...]
void win_admin::send_to_main_list() {
    QString usn=found_users->currentItem()->text();
    int i=0;
    while (i<all_users->count() && all_users->item(i)->text()!=usn) {
        ++i;
    }
    if (i<all_users->count()) if (i<all_users->count()) all_users->setCurrentRow(i);
}

that's not working for me when i select something on the right they say:

QObject::connect: Cannot connect (null)::itemSelectionChanged() to win_admin::send_to_main_list()

i hope, the info i gave was enought.

Answer 1

The error message you get shows the reason why connect() call has failed.

QObject::connect: Cannot connect (null)::itemSelectionChanged() to win_admin::send_to_main_list()

It shows that sender QListWidget* found_users passed to connect() call is null.

You should probably have forgotten to initialize found_users.