How to iterate over wxDataViewTreeCtrl items and serialize them to a file?

apoorv569 · 02-14-2021, 08:04 PM

I have a application that I'm making with wxWidgets which plays audio samples and helps organize them. I have a wxDataViewListCtrl which has several column which holds information about the audio file like filename, path, length, sample rate and all, it also has a toggle column, that when clicked, should add that item to wxDataViewTreeCtrl, and remove when toggled off. I have the wxDataViewTreeCtrl setup as,

Code:

    CollectionView = new wxDataViewTreeCtrl(ViewChoice, BCID_CollectionView, wxDefaultPosition, wxDefaultSize, wxDV_NO_HEADER);

And I added a root node to begin with,

Code:

    wxDataViewItem RootNode = CollectionView->AppendContainer(wxDataViewItem(0), "ROOT", 0);

And this function should add that item to wxDataViewTreeCtrl, SampleListView is wxDataViewListCtrl here,

Code:

void Browser::OnCheckFavorite(wxDataViewEvent& event)
{
    // int selectedRow = SampleListView->GetSelectedRow();
    int selectedRow = SampleListView->ItemToRow(event.GetItem());

    if (selectedRow < 0) return;

    wxString Selection = SampleListView->GetTextValue(selectedRow, 1);

    std::deque<wxDataViewItem> nodes;
    nodes.push_back(RootNode);

    wxDataViewItem foundItem;

    if (SampleListView->GetToggleValue(selectedRow, 0))
    {
        wxLogDebug("Toggle on");

        while(!nodes.empty())
        {
            wxDataViewItem currentItem = nodes.front();
            nodes.pop_front();

            if ( CollectionView->GetItemText(currentItem) == Selection )
            {
                foundItem = currentItem;
                wxLogDebug(CollectionView->GetItemText(currentItem));
                wxLogDebug("Toggle selection: %s", CollectionView->GetItemText(CollectionView->GetSelection()));
                break;
            }

            int row = 0;
            wxDataViewItem child = CollectionView->GetNthChild(currentItem, row);

            while ( child.IsOk() )
            {
                nodes.push_back(child);
                child = CollectionView->GetNthChild(currentItem, row + 1);
                row ++;
            }
        }

        nodes.clear();

        if (foundItem.IsOk())
        {
            const wxString& msg = wxString::Format("%s already added as favorite. Skipping..", Selection);
            wxMessageDialog *msgDialog = new wxMessageDialog(NULL, msg, "Info", wxOK | wxICON_INFORMATION);
            msgDialog->ShowModal();
        }
        else
        {
            wxLogDebug("Sample not found adding as fav.");

            wxDataViewItem selected = CollectionView->GetSelection();
            wxString folder = CollectionView->GetItemText(selected);

            wxLogDebug("Selected: %s", folder);

            CollectionView->AppendItem(RootNode, Selection);

            std::string path = "/home/apoorv/repos/cpp-projects/wxWidgets/SampleBrowser/tree.yaml";

            serialize.SerializeDataViewTreeCtrlItems(path, *CollectionView, RootNode);

            db.UpdateFavoriteColumn(Selection.ToStdString(), 1);
            // db.UpdateFavoriteFolderDatabase(Selection.ToStdString(), folder.ToStdString());
        }
    }

And this code is responsible for serializing the tree items to a yaml file, so I save and load the data back to the application,

Code:

void Serializer::SerializeDataViewTreeCtrlItems(std::string filepath, wxDataViewTreeCtrl& tree, wxDataViewItem& item)
{
    std::ifstream ifin(filepath);

    YAML::Emitter out;

    out << YAML::BeginMap; // Container
    out << YAML::Key << "Container" << YAML::Value << "";

    if (!tree.IsContainer(item))
    {
        out << YAML::Key << "Child";
        out << YAML::BeginMap; // Child

        for ( int i = 0; i < tree.GetChildCount(item); i++ )
        {
            wxString child = tree.GetItemText(tree.GetNthChild(item, i));
            out << YAML::Key << "Item" << YAML::Value << child.ToStdString();
        }

        out << YAML::EndMap; // Child
    }

    out << YAML::EndMap; // Container

    std::ofstream ofout(filepath);
    ofout << out.c_str();
}

But running this code keeps giving me error about invalid index and nothing gets output to the yaml file,

Code:

./src/common/list.cpp(317): assert "Assert failure" failed in Item(): invalid index in wxListBase::Item

What am I doing wrong here?

astrogeek · 02-15-2021, 02:24 PM

Have you investigated why the assertion is failing? That is the most obvious place to start, but you have not included that important part in the code you have posted, so no one here can know what is happening.

What have you done to investigate why that index is invalid?

Based only on the description you have provided (not the code) I would ask:

* Why is the assertion failing? Did you try to find out?

Then in order until you find a problem...

* Is the file being correctly loaded by the application? How do you know?
* Is the exported file format valid? How do you know?
* Is the tree being properly serialized? How do you know?
* Is the item being added to the tree? How do you know?
* Is the root node being created as expected? How do you know?

Please review the Site FAQ for guidance in posting your questions and general forum usage. Especially, read the link in that page, How To Ask Questions The Smart Way. The more effort you put into understanding your problem and framing your questions, the better others can help!

apoorv569 · 02-19-2021, 12:47 AM

Quote:

Originally Posted by astrogeek

Have you investigated why the assertion is failing? That is the most obvious place to start, but you have not included that important part in the code you have posted, so no one here can know what is happening.

What have you done to investigate why that index is invalid?

Based only on the description you have provided (not the code) I would ask:

* Why is the assertion failing? Did you try to find out?

Then in order until you find a problem...

* Is the file being correctly loaded by the application? How do you know?
* Is the exported file format valid? How do you know?
* Is the tree being properly serialized? How do you know?
* Is the item being added to the tree? How do you know?
* Is the root node being created as expected? How do you know?

Please review the Site FAQ for guidance in posting your questions and general forum usage. Especially, read the link in that page, How To Ask Questions The Smart Way. The more effort you put into understanding your problem and framing your questions, the better others can help!

If you can spot the mistake please point me towards it, you don't have to give me an exact fix for the problem.

astrogeek · 02-19-2021, 01:49 AM

I have no idea as stated above. That failed assertion is the clue, but I cannot see it or test it, only the person sitting at the keyboard can do that.

Again, I suggest you start with the failed assertion and then try to answer the questions I posed in the order listed, that will lead you to the cause.

So try to answer that one: Why is that assertion failing? What condition does it assert? What is the state of the relevant variables immediately before the assertion? Add a temporary out << to test that state ahead of the assertion and investigate the thing that is failing. That will always lead you to the cause.