How to add Treewidget Items when clicking on PushButton

[faldzip]

And therefore I can not understand why "createMainTree" is printed out.

I don't understand why this guy is trying to write an application if he does not know any programming language... He has two eclogic class members: 1 public and 1 private...

So maybe just upload a sample project, that reproduce your problem.

This won't help. I tried to understand the code of his project earlier when there was another topic, but it is impossible as this guy has incredible coding style: almost every line starts with different numbers of spaces from the left... he is using global, local and member variables with the same name which he expect to be the same one variable and so on. He has no idea about C++ programming and can't understand that using umbrella doesn't make sense if you don't know how to open it in rainy day!