QTreeWidgetItem setParent

QT-static-prgm

Hi,

I just wanted to set the parent of an QTreeWidget AFTER it is created. But for some reason the function is not available. Any ideas why?? I can set the parent in the constructor and i can read that parent with .parent() but i cannot set it.

dheerendra

use addChild method of QTreeWidgetItem.

QT-static-prgm

Let's say I add a few Childs and subchilds and later I delete the tree widget. Will that automatically delete all entries in the tree widget??

Matt86

In general, any time you delete a UI object any of the children will be deleted too.

jsulm

@QT-static-prgm Why do you think there is no setParent() method? QTreeWidget has setParent() method (inherited from QObject). QObject has setParent method, that means ALL classes derived from QObject have it.

QT-static-prgm

but the qtreewidgetItem has no such function. My compiler gives an error

dheerendra

QTreeWidgetItem does not have setParent. QTreeWidget has. So you should use addChild only. QTreeWidgetItem is not inherited from QObject. QTreeWidget is inherited from QObject. So QTreeWidget has setParent.

QT-static-prgm

All right thank you :D

No i have an other problem.

When i use .clear() to remove everything and then refill the tree it seams that the actual items are still alive. Is there a better way to delete them??

(i noticed that when i refreshed 3 times the connect signal is triggered 3 times)

J.Hilk

@QT-static-prgm

Really? Are you using normal SIGNAL/SLots or Lambda functions?

Lambdas don't get automatically removed.

Anyway you can try something like this, to delete the children.

for(auto a : treewidget->children()
    delete a;

QT-static-prgm

i use lambda.

J.Hilk

@QT-static-prgm

there's your problem then. Either use 'normal' functions, or manually disconnect the connection.
How to do that is taken from here

New way using QMetaObject::Connection
QMetaObject::Connection m_connection;
//…
m_connection = QObject::connect(…);
//…
QObject::disconnect(m_connection);
Works in all cases, including lambda functions or functors.

QT-static-prgm

i changed to singal/slot instead of lambda and had the same problem. Only after i disconnected manual using disconnect(ptr, signal, ptr, slot) it worked.

So it's fine for me that it works, but does that mean that there is still garbage in the memory or is it now correctly deleted??