How to make a QStandardItemModel from QStringList of file paths

Question

i'm new to C++ and Qt and can't seem to find the right solution for this. I want to create a QTreeView using a QStandardItemModel. I have a list of file/folder paths (within a QStringList) structured in a format like this:

Arena/Main/00078/a.txt
Arena/Main/00080/b.txt
Arena/Main/00080/collision/c.txt
Arena/Main/00080/light/d.txt
Arena/Main/00081/e.txt
Characters/f.txt
Characters/Main/g.txt
Characters/Main/someFolder/h.txt

I previously used a QFileSystemModel and made actual temporary directories, iterating through the list as a workaround:

   QDir dir(temp_path);
    if (!dir.exists(dir_string)){
         dir.mkpath(dir_string);
    }
        
    QFile file(filepath_str);
    file.open(QIODevice::WriteOnly);

Which gave me a working result like this: https://i.stack.imgur.com/ITzJz.png

However, the list can reach up to 10,000+ files making it a longer backwards workaround. I want to populate a QTreeView in a similar way using a QStandardItemModel created from the path list.

Answer 1

You can store the created paths in a map like this:

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QMap>
#include <QStandardItemModel>

class QStandardItem;

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    void addPathRecusively(const QStringList &path_parts, QStandardItem *parent, int layer = 1);

    QMap<QString, QStandardItem*> path_item_map_;
    QStandardItemModel model_;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"

#include <QStringList>
#include <QTreeView>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    QStringList filenames =
    {
        "Arena/Main/00078/a1.txt",
        "Arena/Main/00078/a2.txt",
        "Arena/Main/00080/b.txt",
        "Arena/Main/00080/collision/c.txt",
        "Arena/Main/00080/light/d.txt",
        "Arena/Main/00081/e1.txt",
        "Arena/Main/00081/e2.txt",
        "Arena/Main/00081/e3.txt",
        "Characters/f.txt",
        "Characters/Main/g.txt",
        "Characters/Main/someFolder/h.txt",
    };

    for (auto &filename : filenames)
    {
        QStringList parts = filename.split("/");
        parts.pop_back();
        addPathRecusively(parts, model_.invisibleRootItem());
    }

    QTreeView *view = new QTreeView{this};
    view->setModel(&model_);
    this->setCentralWidget(view);
    this->resize(500, 500);
}

MainWindow::~MainWindow()
{
}

void MainWindow::addPathRecusively(const QStringList &path_parts, QStandardItem *parent, int layer)
{
    QStringList path_parts_to_layer;
    std::copy(path_parts.begin(), path_parts.begin() + layer, std::back_inserter(path_parts_to_layer));
    QString path = path_parts_to_layer.join("/");
    auto item = path_item_map_.value(path);
    if (item == nullptr)
    {
        item = new QStandardItem{path_parts_to_layer.last()};
        path_item_map_.insert(path, item);
        parent->appendRow({item, new QStandardItem});
    }

    if (path_parts.length() == layer)
    {
        auto file_count_index = model_.indexFromItem(item).siblingAtColumn(1);
        model_.setData(file_count_index, file_count_index.data().toInt() + 1, Qt::DisplayRole);
    }
    else
        addPathRecusively(path_parts, item, layer + 1);
}