Dummy Delegate creation issue - ListView & Model

dheerendra

Dummy delegates are created with out any data.

Problem :
I have 300 elements in the model. As I keep scrolling list view, delegates are getting created. Now ListView is displaying the 16th element.

Now remove 18-300 elements in the model like the follows.

    beginRemoveRows(QModelIndex(),18,300);
    endRemoveRows();

Now I keep scrolling list view.

Now I see some 5-6 dummy delegates after 18 like 18,19,20,21. However there is no data filled in delegate. It is empty box. I can see Component.onCompleted(..) message for this dummy delegates.

Model is publishing the row count as 17 only.
List view is not calling data(..) method for 18,19,20,21 like that.
But I see the dummy delegates without data.

This is issue is happening only with specific example. It always happens with my example.
I tried to reproduce the issue with another example using ListView. Not able to see this.

Any inputs on why these dummy delegates are getting created ?
Any inputs to troubleshoot ?

dheerendra

I am able to solve this issue. I used timer to remove the elements again. Inside the timer slots calling the remove rows by calling beginRemoveRows(..). I have no explanation how this works.
But this worked and dummy rows are not visible.

    First Time  - 

    beginRemoveRows(QModelIndex(),m_start,m_end);
    this->m_timer.start();
    endRemoveRows();

   Inside the timer slots -

   void MyModel::timerSlot(){
    beginRemoveRows(QModelIndex(),m_start,m_end);
    endRemoveRows();
    this->m_timer.stop();

}

sierdzio

That's very weird! Thanks for sharing the solution!

dheerendra

@sierdzio yes, it is very weird. I struggled to get the solution & explanation. However not successful. It is software & it worked!!!. Moving on now..