CheckableProxyModel - saving/loading check states

Orkblutt

Hello,

I'm using the Andre Somers 's CheckableProxyModel to add the possibility to check elements in a QTreeView. I'm using QFileSystemModel as model but what I'd like to achieve could work with any models (lazzy or not).
I'd like to be able to save and load check state. I 'm not sure what direction I should choose.
I'm saving the current states as an include/exclude model.
Example:

include c:\test_folder
include c:\users\bruno\desktop
exclude c:\users\bruno\desktop\file.txt

Should I expand every node referenced in my include/exclude list to apply the states or could I overload CheckableProxyModel::resolveCheckStateRole to compute the state based on the list ?

Any other idea are welcome!! :)

SGaist

Hi and welcome to devnet,

What you say saving and loading, do you mean like in saving the state to a file, then read it again and modify your model ?

Orkblutt

Hi. Thank you.

Yes. Sorry if I'm not really clear. The purpose is to load/restore checked states on a QTreeView based on a QFileSystemModel. I'm using the excellent Andre Somers 's CheckableProxyModel class for the checkboxes part.
I'm really new to Qt and I'm Learning the nice Qt's model/view. I'm fan!

So let's try to explain more my problem:
I want to restore, a previous checked state, saved on sqlite db, on my file system tree.
Since QFileSystemModel is a "lazy" model, the full file system isn't loaded on the model. It's populated each time we expand a node. The goal is to load the checked state in a lazy manner too.

I implemented an (uggly) alternative way: expanding each node referenced in my "checked list" and checkit.
the QModelIndex get by myQFSM->index("C:\Toto\Titi.txt") doesn't have a valide row/column index if the parents are not deployed yet.
So here the trick in a thread:

 QSqlQuery query(sQuery);
        while (query.next())
        {
            // paths are stored like this:
            // C:|Folder|File.txt
            QString path = query.value(0).toString().replace('|', QDir::separator());

            // let's split the path
            QStringList nodeString = path.split(QDir::separator(), QString::SkipEmptyParts);
            QString name = "";
            QString tmppath = "";

            uint uCount = 0;
            foreach (name, nodeString)
            {
                qDebug() << name;
                tmppath += name;
                // add separator is we're not on a leaf (file)
                if(uCount < nodeString.size() - 1)
                    tmppath += QDir::separator();


                // let's take index from our QFSM model
                QModelIndex idx = _foldermodel->index(tmppath, 0);

                if(!idx.isValid()) continue;
                
                // map it on our proxy model (the one used in our QTreeView and checkbox)
                QModelIndex index = _filter->mapFromSource(idx);
                if(index.isValid())
                {
                    ui->treeView->expand(index);
                    // found somewhere scrollto is waiting for a full populated node
                    // TODO: better to use the QFileSystemModel::directoryLoaded signal
                    ui->treeView->scrollTo(index);

                    // We are now on our checked item... let's check it!
                    if(uCount == nodeString.size() - 1)
                    {
                        _filter->setCheckedState(index, true);
                        ui->treeView->collapseAll();
                    }
                }
                uCount++;
            }
        }

It is doing the job, it's pretty fast... but it's not very elegant.

The lazy way should bring an other problem: maintain the full/half checked for parents. We need to check if a parent (contained our checked list) dosn't have unchecked item.

If someone have a nice idea, I'll be happy to look at it. If not I'll use the uggly way :)

SGaist

One possibility might be to use directoryLoaded.