[Interest] Model for QTreeView

[Alex Strickland]

On 2012/11/19 06:27 PM, Alex Strickland wrote:

> Yes, I have, but as you might judge from the above, it's still a bit hazy!

My attempts don't work, can anyone say why?

TIA
-- 
Regards
Alex
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/*
 * Copyright Electric Bridge Software 2011,2012.
 */

#include "treemodel.h"

TreeModel::TreeModel()
{
    TreeStruct treeStruct;

    treeStruct.name = "one";
    treeStruct.leaves << "one/one" << "one/two";
    m_treeData << treeStruct;

    treeStruct.name = "two";
    treeStruct.leaves.clear();
    m_treeData << treeStruct;

    treeStruct.name = "three";
    treeStruct.leaves << "three/one" << "three/two" << "three/three";
    m_treeData << treeStruct;
}

QVariant TreeModel::data(const QModelIndex &index,
                         int role) const
{
    if (!index.isValid())
        return QVariant();

    if (role != Qt::DisplayRole)
        return QVariant();

    if (index.internalId() >= 0)
        return QVariant(m_treeData[ index.internalId() ].leaves[ index.row() ]);

    return QVariant(m_treeData[ index.row() ].name);
}

Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
{
    if (!index.isValid())
        return 0;

    return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
}

QVariant TreeModel::headerData(int section,
                               Qt::Orientation orientation,
                               int role) const
{
    if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
        return QVariant("header");

    return QVariant();
}

QModelIndex TreeModel::index(int row,
                             int column,
                             const QModelIndex &parent) const
{
    QModelIndex modelIndex;
    if (!hasIndex(row, column, parent)) {
        modelIndex = QModelIndex();
    }
    else {
        // Then it's the root, and we can return an id of row via createIndex
        if (!parent.isValid())
            modelIndex = createIndex(row, column, row);
        else
        // else it's not the root, and the id is -1
            modelIndex = createIndex(row, column, -1);
    }
    return modelIndex;
}

QModelIndex TreeModel::parent(const QModelIndex &index) const
{
    QModelIndex modelIndex;
    if (!index.isValid()) {
        modelIndex = QModelIndex();
    }
    else {
            // it's a leaf, so the parent is
        if (index.internalId() == -1) {
            modelIndex = createIndex(index.row(),
                                     index.column(),
                                     index.row());
        }
        else {
            // else it's the parent and we must return an invalid Model Index
            modelIndex = QModelIndex();
        }
    }
    return modelIndex;
}

int TreeModel::rowCount(const QModelIndex &parent) const
{
    int rowCount;
    if (!parent.isValid())
        rowCount = m_treeData.length();
    else
        rowCount = m_treeData[ parent.row() ].leaves.length();
    return rowCount;
}

int TreeModel::columnCount(const QModelIndex &parent) const
{
    return 1;
}
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/*
 * Copyright Electric Bridge Software 2011,2012.
 */

#ifndef TREEMODEL_H
#define TREEMODEL_H

#include <QAbstractItemModel>
#include <QModelIndex>
#include <QVariant>

typedef struct TreeStruct
{
    QString name;
    QList<QString> leaves;
};

class TreeModel : public QAbstractItemModel
{
public:
    TreeModel();
    QVariant data(const QModelIndex &index,
                  int role) const;
    Qt::ItemFlags flags(const QModelIndex &index) const;
    QVariant headerData(int section,
                        Qt::Orientation orientation,
                        int role = Qt::DisplayRole) const;
    QModelIndex index(int row,
                      int column,
                      const QModelIndex &parent = QModelIndex()) const;
    QModelIndex parent(const QModelIndex &index) const;
    int rowCount(const QModelIndex &parent = QModelIndex()) const;
    int columnCount(const QModelIndex &parent = QModelIndex()) const;
private:
    QList<TreeStruct> m_treeData;
};

#endif // TREEMODEL_H