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// Copyright (C) 2024 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
/*
treemodel.cpp
Provides a simple tree model to show how to create and use hierarchical
models.
*/
#include "treemodel.h"
#include "treeitem.h"
#include <QFile>
#include <QStringList>
#include <QStack>
using namespace Qt::StringLiterals;
//! [0]
TreeModel::TreeModel(QObject *parent)
: QAbstractItemModel(parent)
, rootItem(std::make_unique<TreeItem>(QVariantList{tr("Title"), tr("Summary")}))
{
QFile file(":/content.txt"_L1);
file.open(QIODevice::ReadOnly | QIODevice::Text);
setupModelData(QStringView{QString::fromUtf8(file.readAll())}.split(u'\n'), rootItem.get());
file.close();
}
//! [0]
//! [1]
TreeModel::~TreeModel() = default;
//! [1]
//! [2]
int TreeModel::columnCount(const QModelIndex &parent) const
{
if (parent.isValid())
return static_cast<TreeItem*>(parent.internalPointer())->columnCount();
return rootItem->columnCount();
}
//! [2]
//! [3]
QVariant TreeModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid() || role != Qt::DisplayRole)
return {};
const auto *item = static_cast<const TreeItem*>(index.internalPointer());
return item->data(index.column());
}
//! [3]
//! [4]
Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
{
return index.isValid()
? QAbstractItemModel::flags(index) : Qt::ItemFlags(Qt::NoItemFlags);
}
//! [4]
//! [5]
QVariant TreeModel::headerData(int section, Qt::Orientation orientation,
int role) const
{
return orientation == Qt::Horizontal && role == Qt::DisplayRole
? rootItem->data(section) : QVariant{};
}
//! [5]
//! [6]
QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) const
{
if (!hasIndex(row, column, parent))
return {};
TreeItem *parentItem = parent.isValid()
? static_cast<TreeItem*>(parent.internalPointer())
: rootItem.get();
if (auto *childItem = parentItem->child(row))
return createIndex(row, column, childItem);
return {};
}
//! [6]
//! [7]
QModelIndex TreeModel::parent(const QModelIndex &index) const
{
if (!index.isValid())
return {};
auto *childItem = static_cast<TreeItem*>(index.internalPointer());
TreeItem *parentItem = childItem->parentItem();
return parentItem != rootItem.get()
? createIndex(parentItem->row(), 0, parentItem) : QModelIndex{};
}
//! [7]
//! [8]
int TreeModel::rowCount(const QModelIndex &parent) const
{
if (parent.column() > 0)
return 0;
const TreeItem *parentItem = parent.isValid()
? static_cast<const TreeItem*>(parent.internalPointer())
: rootItem.get();
return parentItem->childCount();
}
//! [8]
void TreeModel::setupModelData(const QList<QStringView> &lines, TreeItem *parent)
{
struct ParentIndentation
{
TreeItem *parent;
qsizetype indentation;
};
QStack<ParentIndentation> state;
state.push({parent, 0});
for (const auto &line : lines) {
qsizetype position = 0;
for ( ; position < line.length() && line.at(position).isSpace(); ++position) {
}
const QStringView lineData = line.sliced(position).trimmed();
if (!lineData.isEmpty()) {
// Read the column data from the rest of the line.
const auto columnStrings = lineData.split(u'\t', Qt::SkipEmptyParts);
QVariantList columnData;
columnData.reserve(columnStrings.count());
for (const auto &columnString : columnStrings)
columnData << columnString.toString();
if (position > state.top().indentation) {
// The last child of the current parent is now the new parent
// unless the current parent has no children.
auto *lastParent = state.top().parent;
if (lastParent->childCount() > 0)
state.push({lastParent->child(lastParent->childCount() - 1), position});
} else {
while (position < state.top().indentation && !state.isEmpty())
state.pop();
}
// Append a new item to the current parent's list of children.
auto *lastParent = state.top().parent;
lastParent->appendChild(std::make_unique<TreeItem>(columnData, lastParent));
}
}
}
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