Verwendung von QtAbstractItemModel in Android Studio-Projekten

C:\Qt\Examples\Qt-<patch-release-number>\platforms\android\<example-name>

Rectangle {
    id: mainRectangle

    property AbstractItemModel dataModel

    TableView {
        id: tableView

        model: mainRectangle.dataModel

        anchors {fill: parent; margins: 20}
        columnSpacing: 4
        rowSpacing: 6
        boundsBehavior: TableView.OvershootBounds
        clip: true

        ScrollBar.vertical: ScrollBar {
           policy: ScrollBar.AsNeeded
        }
        ScrollBar.horizontal: ScrollBar{
           policy: ScrollBar.AsNeeded
        }

        delegate: Rectangle {
            implicitWidth: (tableView.height > tableView.width) ? tableView.width / 10 : tableView.height / 5
            implicitHeight: implicitWidth

            required property var model

            color: "#2CDE85"
            border {color: "#00414A"; width: 2}

            TextEdit {
                // Calls MyDataModel::data to get data based on the roles.
                // Called in Qt qtMainLoopThread thread context.
                //
                // After editing is finished, call MyDataModel::setData()
                // to update the value of selected cell.
                onEditingFinished: parent.model.edit = text

                text: parent.model.display
                font {pixelSize: 26; bold: true}
                padding: 5
                anchors.fill: parent
                wrapMode: TextEdit.Wrap
                horizontalAlignment: TextEdit.AlignHCenter
                verticalAlignment: TextEdit.AlignVCenter
            }
        }

/*
* Initializes the two-dimensional array list with following content:
* [] [] [] [] 1A 1B 1C 1D
* [] [] [] [] 2A 2B 2C 2D
* [] [] [] [] 3A 3B 3C 3D
* [] [] [] [] 4A 4B 4C 4D
* Threading: called in Android main thread context.
*/
public MyDataModel() {

/*
* Returns the count of columns.
* Threading: called in Android main thread context.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public int columnCount(QtModelIndex qtModelIndex) {
    return m_columns;
}

/*
* Returns the count of rows.
* Threading: called in Android main thread context.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public int rowCount(QtModelIndex qtModelIndex) {
    return m_dataList.size();
}

/*
* Returns the data to QML based on the roleNames
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public Object data(QtModelIndex qtModelIndex, int role) {
    if (role == ROLE_DISPLAY) {
        Cell elementForEdit = m_dataList.get(qtModelIndex.row()).get(qtModelIndex.column());
        return elementForEdit.getValue();
    }
    Log.w(TAG, "data(): unrecognized role: " + role);
    return null;
}

/*
* Defines what string i.e. role in QML side gets the data from Java side.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public HashMap<Integer, String> roleNames() {
    HashMap<Integer, String> roles = new HashMap<>();
    roles.put(ROLE_DISPLAY, "display");
    roles.put(ROLE_EDIT, "edit");
    return roles;
}

/*
* Returns a new index model.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public QtModelIndex index(int row, int column, QtModelIndex parent) {
    return createIndex(row, column, 0);
}

/*
* Returns a parent model.
* Threading: not used called in this example.
*/
@Override
synchronized public QtModelIndex parent(QtModelIndex qtModelIndex) {
    return new QtModelIndex();
}

/*
* Gets called when model data is edited from QML side.
* Sets the role data for the item at index to value,
* if given index is valid and if data in given index truly changed.
*/
@Override
synchronized public boolean setData(QtModelIndex index, Object value, int role) {
    Cell cellAtIndex = m_dataList.get(index.row()).get(index.column());
    String cellValueAtIndex = cellAtIndex.getValue();
    if (!index.isValid() || role != ROLE_EDIT
            || Objects.equals(cellValueAtIndex, value.toString())) {
        return false;
    }
    cellAtIndex.setValue(value.toString());
    // Send dataChanged() when data was successfully set.
    dataChanged(index, index, new int[]{role});
    return true;
}

/*
* Adds a row.
* Threading: called in Android main thread context.
*/
synchronized public void addRow() {
    if (m_columns > 0 && m_dataList.size() < MAX_ROWS_AND_COLUMNS) {
        beginInsertRows(new QtModelIndex(), m_dataList.size(), m_dataList.size());
        m_dataList.add(generateNewRow());
        endInsertRows();
    }
}

/*
* Removes a row.
* Threading: called in Android main thread context.
*/
synchronized public void removeRow() {
    if (m_dataList.size() > 1) {
        beginRemoveRows(new QtModelIndex(), m_dataList.size() - 1, m_dataList.size() - 1);
        m_dataList.remove(m_dataList.size() - 1);
        endRemoveRows();
    }
}

/*
* Adds a column.
* Threading: called in Android main thread context.
*/
synchronized public void addColumn() {
    if (!m_dataList.isEmpty() && m_columns < MAX_ROWS_AND_COLUMNS) {
        beginInsertColumns(new QtModelIndex(), m_columns, m_columns);
        generateNewColumn();
        m_columns += 1;
        endInsertColumns();
    }
}

/*
* Removes a column.
* Threading: called in Android main thread context.
*/
synchronized public void removeColumn() {
    if (m_columns > 1) {
        int columnToRemove = m_columns - 1;
        beginRemoveColumns(new QtModelIndex(), columnToRemove, columnToRemove);
        for (int row = 0; row < m_dataList.size(); row++)
            m_dataList.get(row).remove(columnToRemove);
        m_columns -= 1;
        endRemoveColumns();
    }
}

private final MyDataModel m_model = new MyDataModel();

/*
* Returns the count of columns.
* Threading: called in Android main thread context.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public int columnCount(QtModelIndex qtModelIndex) {
    return m_columns;
}

/*
* Returns the count of rows.
* Threading: called in Android main thread context.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public int rowCount(QtModelIndex qtModelIndex) {
    return m_dataList.size();
}

/*
* Returns the data to QML based on the roleNames
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public Object data(QtModelIndex qtModelIndex, int role) {
    if (role == ROLE_DISPLAY) {
        Cell elementForEdit = m_dataList.get(qtModelIndex.row()).get(qtModelIndex.column());
        return elementForEdit.getValue();
    }
    Log.w(TAG, "data(): unrecognized role: " + role);
    return null;
}

/*
* Defines what string i.e. role in QML side gets the data from Java side.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public HashMap<Integer, String> roleNames() {
    HashMap<Integer, String> roles = new HashMap<>();
    roles.put(ROLE_DISPLAY, "display");
    roles.put(ROLE_EDIT, "edit");
    return roles;
}

/*
* Returns a new index model.
* Threading: called in Qt qtMainLoopThread thread context.
*/
@Override
synchronized public QtModelIndex index(int row, int column, QtModelIndex parent) {
    return createIndex(row, column, 0);
}

/*
* Returns a parent model.
* Threading: not used called in this example.
*/
@Override
synchronized public QtModelIndex parent(QtModelIndex qtModelIndex) {
    return new QtModelIndex();
}

/*
* Gets called when model data is edited from QML side.
* Sets the role data for the item at index to value,
* if given index is valid and if data in given index truly changed.
*/
@Override
synchronized public boolean setData(QtModelIndex index, Object value, int role) {
    Cell cellAtIndex = m_dataList.get(index.row()).get(index.column());
    String cellValueAtIndex = cellAtIndex.getValue();
    if (!index.isValid() || role != ROLE_EDIT
            || Objects.equals(cellValueAtIndex, value.toString())) {
        return false;
    }
    cellAtIndex.setValue(value.toString());
    // Send dataChanged() when data was successfully set.
    dataChanged(index, index, new int[]{role});
    return true;
}