string list model example
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#ifndef MODEL_H
#define MODEL_H
#include <QAbstractListModel>
#include <QObject>
#include <QStringList>
class StringListModel : public QAbstractListModel
{
Q_OBJECT
public:
StringListModel(const QStringList &strings, QObject *parent = 0)
: QAbstractListModel(parent), stringList(strings) {}
int rowCount(const QModelIndex &parent = QModelIndex()) const;
QVariant data(const QModelIndex &index, int role) const;
QVariant headerData(int section, Qt::Orientation orientation,
int role = Qt::DisplayRole) const;
Qt::ItemFlags flags(const QModelIndex &index) const;
bool setData(const QModelIndex &index, const QVariant &value,
int role = Qt::EditRole);
bool insertRows(int position, int rows, const QModelIndex &index = QModelIndex());
bool removeRows(int position, int rows, const QModelIndex &index = QModelIndex());
private:
QStringList stringList;
};
#endif
/*
model.cpp
A simple model that uses a QStringList as its data source.
*/
#include "model.h"
/*!
Returns the number of items in the string list as the number of rows
in the model.
*/
int StringListModel::rowCount(const QModelIndex &parent) const
{
return stringList.count();
}
/*!
Returns an appropriate value for the requested data.
If the view requests an invalid index, an invalid variant is returned.
Any valid index that corresponds to a string in the list causes that
string to be returned.
*/
QVariant StringListModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();
if (index.row() >= stringList.size())
return QVariant();
if (role == Qt::DisplayRole)
return stringList.at(index.row());
else
return QVariant();
}
/*!
Returns the appropriate header string depending on the orientation of
the header and the section. If anything other than the display role is
requested, we return an invalid variant.
*/
QVariant StringListModel::headerData(int section, Qt::Orientation orientation,
int role) const
{
if (role != Qt::DisplayRole)
return QVariant();
if (orientation == Qt::Horizontal)
return QString("Column %1").arg(section);
else
return QString("Row %1").arg(section);
}
/*!
Returns an appropriate value for the item's flags. Valid items are
enabled, selectable, and editable.
*/
Qt::ItemFlags StringListModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return Qt::ItemIsEnabled;
return QAbstractItemModel::flags(index) | Qt::ItemIsEditable;
}
/*!
Changes an item in the string list, but only if the following conditions
are met:
* The index supplied is valid.
* The index corresponds to an item to be shown in a view.
* The role associated with editing text is specified.
The dataChanged() signal is emitted if the item is changed.
*/
bool StringListModel::setData(const QModelIndex &index,
const QVariant &value, int role)
{
if (index.isValid() && role == Qt::EditRole) {
stringList.replace(index.row(), value.toString());
emit dataChanged(index, index);
return true;
}
return false;
}
/*!
Inserts a number of rows into the model at the specified position.
*/
bool StringListModel::insertRows(int position, int rows, const QModelIndex &parent)
{
beginInsertRows(QModelIndex(), position, position+rows-1);
for (int row = 0; row < rows; ++row) {
stringList.insert(position, "");
}
endInsertRows();
return true;
}
/*!
Removes a number of rows from the model at the specified position.
*/
bool StringListModel::removeRows(int position, int rows, const QModelIndex &parent)
{
beginRemoveRows(QModelIndex(), position, position+rows-1);
for (int row = 0; row < rows; ++row) {
stringList.removeAt(position);
}
endRemoveRows();
return true;
}
/*!
The main function for the string list model example. This creates and
populates a model with values from a string list then displays the
contents of the model using a QListView widget.
*/
#include <QAbstractItemModel>
#include <QApplication>
#include <QListView>
#include "model.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
// Unindented for quoting purposes:
QStringList numbers;
numbers << "One" << "Two" << "Three" << "Four" << "Five";
QAbstractItemModel *model = new StringListModel(numbers);
QListView *view = new QListView;
view->setWindowTitle("View onto a string list model");
view->setModel(model);
model->insertRows(5, 7, QModelIndex());
for (int row = 5; row < 12; ++row) {
QModelIndex index = model->index(row, 0, QModelIndex());
model->setData(index, QString::number(row+1));
}
view->show();
return app.exec();
}
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