regexpmodel.cpp

Qt4的一些例子

#include <QtCore>

#include "regexpmodel.h"
#include "regexpparser.h"

RegExpModel::RegExpModel(QObject *parent)
    : QAbstractItemModel(parent)
{
    rootNode = 0;
}

RegExpModel::~RegExpModel()
{
    delete rootNode;
}

void RegExpModel::setRootNode(Node *node)
{
    delete rootNode;
    rootNode = node;
    reset();
}

QModelIndex RegExpModel::index(int row, int column,
                               const QModelIndex &parent) const
{
    if (!rootNode)
        return QModelIndex();
    Node *parentNode = nodeFromIndex(parent);
    return createIndex(row, column, parentNode->children[row]);
}

QModelIndex RegExpModel::parent(const QModelIndex &child) const
{
    Node *node = nodeFromIndex(child);
    if (!node)
        return QModelIndex();
    Node *parentNode = node->parent;
    if (!parentNode)
        return QModelIndex();
    Node *grandparentNode = parentNode->parent;
    if (!grandparentNode)
        return QModelIndex();

    int row = grandparentNode->children.indexOf(parentNode);
    return createIndex(row, child.column(), parentNode);
}

int RegExpModel::rowCount(const QModelIndex &parent) const
{
    Node *parentNode = nodeFromIndex(parent);
    if (!parentNode)
        return 0;
    return parentNode->children.count();
}

int RegExpModel::columnCount(const QModelIndex & /* parent */) const
{
    return 2;
}

QVariant RegExpModel::data(const QModelIndex &index, int role) const
{
    if (role != Qt::DisplayRole)
        return QVariant();

    Node *node = nodeFromIndex(index);
    if (!node)
        return QVariant();

    if (index.column() == 0) {
        switch (node->type) {
        case Node::RegExp:
            return tr("RegExp");
        case Node::Expression:
            return tr("Expression");
        case Node::Term:
            return tr("Term");
        case Node::Factor:
            return tr("Factor");
        case Node::Atom:
            return tr("Atom");
        case Node::Terminal:
            return tr("Terminal");
        default:
            return tr("Unknown");
        }
    } else if (index.column() == 1) {
        return node->str;
    }
    return QVariant();
}

QVariant RegExpModel::headerData(int section,
                                 Qt::Orientation orientation,
                                 int role) const
{
    if (orientation == Qt::Horizontal && role == Qt::DisplayRole) {
        if (section == 0) {
            return tr("Node");
        } else if (section == 1) {
            return tr("Value");
        }
    }
    return QVariant();
}

Node *RegExpModel::nodeFromIndex(const QModelIndex &index) const
{
    if (index.isValid()) {
        return static_cast<Node *>(index.internalPointer());
    } else {
        return rootNode;
    }
}