问题
I am implementing tree view, I have sub classed my model and view. initially I am populating all the top level items and I don't know how many child's are there for each top level items but I know all the top level items has a child's, so I have re-implemented hasChildren() function and pass true for all the top level items, but I am not able to see + sign for the top level items even i pass true. Please let me know the problem
Thanks in advance.
来源：https://stackoverflow.com/questions/29817018/not-able-to-see-plus-sign-even-if-i-pass-true-from-haschildren-function-in-qt