How to update QTreeView?

ahsan737

Greetings,
I am building the QTreeView model from CSV data, How can I update/repopulate view if file data is changed/updated?
Looking forward to the considerate reply.

Best regards,
Ahsan

Mucip

Hi,
You may celar all data in the tree and reload it from csv file.

Regards,
Mucip:)

JonB

@ahsan737
If you repopulate (or regenerate) the model by reloading the file, the QTreeView will see that and refresh for you, without you needing to do anything else.

You can also recognise that an external file has been modified via https://doc.qt.io/qt-5/qfilesystemwatcher.html.

ahsan737

@JonB if I regenerate then it doubles the information.

Mucip

@ahsan737 ,
That's why I said you need to clear all list first. :)

Regards,
Mucip:)

JonB

@ahsan737 , @Mucip
Sorry, I don't understand these two posts. If your QTreeView is bound to a model, it shows what is in that model. It does not "retain previous stuff". Where do you get "doubles the information" or "need to clear it first" from? What are you talking about clearing, there is no QTreeView::clear()? Obviously "regenerate the model" does not mean "append to whatever is presently there".

J.Hilk

@JonB

I think the OP did not use a proper model but rather the (in)famous setItemWidget function...

JonB

@J-Hilk
@ahsan737 wrote:

I am building the QTreeView model from CSV data,

Clearly your powers of guessing/interpreting are better than mine! ;)

Mucip

@JonB ,
I mean;
ui->someTreeWidget->clear();

Regards,
Mucip:)

JonB

@Mucip
OK, but that is QTreeWidget::clear(), and the OP's question is "How to update QTreeView", QTreeWidget has never been mentioned. I'm sure he would ask about QTreeWidget not just QTreeView if that's what he wants to know about. Ho-hum.

ahsan737

@J-Hilk I am creating the QTreeView model using this method:

//--------------------Tree View Model--------------------------
QStandardItemModel *model=new QStandardItemModel (this);
rootItem=model->invisibleRootItem();

QStandardItem *TitleItem=new QStandardItem ("\n"+Title_line.at(i)+"\n"+second_line.at(i)+"\n"+third_line.at(i));

TitleItem->setIcon(QIcon(":/img/img/saved_data.jpg.png"));

//defining tree structure
rootItem->appendRow(TitleItem);
ui->treeView->setModel(model);

JonB

@ahsan737
I did say earlier to answer both your questions:

@ahsan737
If you repopulate (or regenerate) the model by reloading the file, the QTreeView will see that and refresh for you, without you needing to do anything else.
.
You can also recognise that an external file has been modified via https://doc.qt.io/qt-5/qfilesystemwatcher.html.

You said:

@JonB if I regenerate then it doubles the information.

But it should not do that. So what did you do?

ahsan737

@JonB thank you for the considerate response, can you please help with a sample code then it will be easy for me to understand, I am not good with Qt.

JonB

@ahsan737
You should show what code you have used to "regenerate then it doubles the information".

ahsan737

This post is deleted!

ahsan737

@JonB I have done that successfully, thank you for guidance. I was only clearing model and rootItem data but forgot to reset variable values.

JonB

@ahsan737
This is why it's always good to show code :)