Model view controller
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#ifndef VIEW_H
#define VIEW_H
#include <QAbstractItemView>
#include <QItemSelection>
#include <QItemSelectionModel>
#include <QModelIndex>
#include <QRect>
#include <QSize>
#include <QWidget>
class LinearView : public QAbstractItemView
{
Q_OBJECT
public:
LinearView(QWidget *parent = 0);
QRect itemViewportRect(const QModelIndex &index) const;
void ensureVisible(const QModelIndex &index);
QModelIndex itemAt(int x, int y) const;
protected slots:
/*void dataChanged(const QModelIndex &topLeft, const QModelIndex
&bottomRight);*/
void rowsInserted(const QModelIndex &parent, int start, int end);
void rowsRemoved(const QModelIndex &parent, int start, int end);
/*void selectionChanged(const QItemSelection &deselected, const QItemSelection &selected);
void verticalScrollbarAction(int action);
void horizontalScrollbarAction(int action);*/
protected:
void setSelection(const QRect&, QItemSelectionModel::SelectionFlags command);
QRect selectionViewportRect(const QItemSelection &selection) const;
QRect itemRect(const QModelIndex &item) const;
bool isIndexHidden(const QModelIndex &index) const;
int horizontalOffset() const;
int verticalOffset() const;
QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction,
Qt::KeyboardModifiers modifiers);
void paintEvent(QPaintEvent *event);
void resizeEvent(QResizeEvent *event);
QSize sizeHint() const;
private:
int rows(const QModelIndex &index = QModelIndex()) const;
void updateGeometries();
};
#endif
/*!
view.cpp
Provides a view to represent a one-dimensional sequence of integers
obtained from a list model as a series of rows.
*/
#include <QAbstractItemModel>
#include <QBrush>
#include <QItemSelection>
#include <QPainter>
#include <QPaintEvent>
#include <QPen>
#include <QPoint>
#include <QResizeEvent>
#include <QScrollBar>
#include <QSizePolicy>
#include "view.h"
LinearView::LinearView(QWidget *parent)
: QAbstractItemView(parent)
{
setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
}
/*!
Returns the position of the item in viewport coordinates.
*/
QRect LinearView::itemViewportRect(const QModelIndex &index) const
{
QRect rect = itemRect(index);
QRect result(rect.left() - horizontalScrollBar()->value(),
rect.top() - verticalScrollBar()->value(),
rect.width(), viewport()->height());
return result;
}
/*!
Returns the rectangle of the item at position \a index in the
model. The rectangle is in contents coordinates.
*/
QRect LinearView::itemRect(const QModelIndex &index) const
{
if (!index.isValid())
return QRect();
else
return QRect(index.row(), 0, 1, 1);
}
void LinearView::ensureVisible(const QModelIndex &index)
{
QRect area = viewport()->rect();
QRect rect = itemViewportRect(index);
if (rect.left() < area.left())
horizontalScrollBar()->setValue(
horizontalScrollBar()->value() - rect.left());
else if (rect.right() > area.right())
horizontalScrollBar()->setValue(
horizontalScrollBar()->value() + rect.left() - area.width());
}
/*!
Returns the item that covers the coordinate given in the view.
*/
QModelIndex LinearView::itemAt(int x, int /* y */) const
{
int row = x + horizontalScrollBar()->value();
return model()->index(row, 0, QModelIndex());
}
//void LinearView::dataChanged(const QModelIndex &/* topLeft */,
// const QModelIndex &/* bottomRight */)
//{
// updateGeometries();
// if (isVisible())
// repaint();
//}
void LinearView::rowsInserted(const QModelIndex &/* parent */, int /* start */,
int /* end */)
{
updateGeometries();
if (isVisible())
repaint();
}
void LinearView::rowsRemoved(const QModelIndex &/* parent */, int /* start */,
int /* end */)
{
updateGeometries();
if (isVisible())
repaint();
}
/*
void LinearView::verticalScrollbarAction(int action)
{
}
void LinearView::horizontalScrollbarAction(int action)
{
}
*/
/*!
Select the items in the model that lie within the rectangle specified by
\a rect, using the selection \a command.
*/
void LinearView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
QModelIndex leftIndex = itemAt(rect.left(), 0);
QModelIndex rightIndex = itemAt(rect.right(), 0);
QItemSelection selection(leftIndex, rightIndex);
selectionModel()->select(selection, command);
}
QModelIndex LinearView::moveCursor(QAbstractItemView::CursorAction cursorAction,
Qt::KeyboardModifiers)
{
QModelIndex current = currentIndex();
switch (cursorAction) {
case MoveLeft:{
if (current.row() > 0)
return model()->index(current.row() - 1, 0, QModelIndex());
else
return model()->index(0, 0, QModelIndex());
break;}
case MoveRight:{
if (current.row() < rows(current) - 1)
return model()->index(current.row() + 1, 0, QModelIndex());
else
return model()->index(rows(current) - 1, 0,QModelIndex());
break;}
case MoveUp:
return current;
case MoveDown:
return current;
case MovePageUp:
return current;
case MovePageDown:
return current;
case MoveHome:
return model()->index(0, 0, QModelIndex());
case MoveEnd:
return model()->index(rows(current) - 1, 0, QModelIndex());
default:
return current;
}
}
int LinearView::horizontalOffset() const
{
return horizontalScrollBar()->value();
}
int LinearView::verticalOffset() const
{
return verticalScrollBar()->value();
}
/*!
Returns a rectangle corresponding to the selection in viewport cooridinates.
*/
QRect LinearView::selectionViewportRect(const QItemSelection &selection) const
{
int ranges = selection.count();
if (ranges == 0)
return QRect();
// Note that we use the top and bottom functions of the selection range
// since the data is stored in rows.
int firstRow = selection.at(0).top();
int lastRow = selection.at(0).top();
for (int i = 0; i < ranges; ++i) {
firstRow = qMin(firstRow, selection.at(i).top());
lastRow = qMax(lastRow, selection.at(i).bottom());
}
QModelIndex firstItem = model()->index(qMin(firstRow, lastRow), 0,
QModelIndex());
QModelIndex lastItem = model()->index(qMax(firstRow, lastRow), 0,
QModelIndex());
QRect firstRect = itemViewportRect(firstItem);
QRect lastRect = itemViewportRect(lastItem);
return QRect(firstRect.left(), firstRect.top(),
lastRect.right() - firstRect.left(), firstRect.height());
}
void LinearView::paintEvent(QPaintEvent *event)
{
QPainter painter(viewport());
QRect updateRect = event->rect();
QBrush background(Qt::black);
QPen foreground(Qt::white);
painter.fillRect(updateRect, background);
painter.setPen(foreground);
QModelIndex firstItem = itemAt(updateRect.left(), updateRect.top());
if (!firstItem.isValid())
firstItem = model()->index(0, 0, QModelIndex());
QModelIndex lastItem = itemAt(updateRect.right(), updateRect.bottom());
if (!lastItem.isValid())
lastItem = model()->index(rows() - 1, 0, QModelIndex());
int x = updateRect.left();
//int top = updateRect.top();
//int bottom = updateRect.bottom();
int row = firstItem.row();
QModelIndex index = model()->index(row, 0, QModelIndex());
int value = model()->data(index, Qt::DisplayRole).toInt();
int midPoint = viewport()->height()/2;
int y2 = midPoint - int(value * midPoint/255.0);
while (row <= lastItem.row()) {
QModelIndex index = model()->index(row, 0, QModelIndex());
int value = model()->data(index, Qt::DisplayRole).toInt();
int y1 = y2;
y2 = midPoint - int(value * midPoint/255.0);
painter.drawLine(x-1, y1, x, y2);
++row; ++x;
}
}
void LinearView::resizeEvent(QResizeEvent * /* event */)
{
updateGeometries();
}
void LinearView::updateGeometries()
{
if (viewport()->width() < rows()) {
horizontalScrollBar()->setPageStep(viewport()->width());
horizontalScrollBar()->setRange(0, rows() - viewport()->width() - 1);
}
}
QSize LinearView::sizeHint() const
{
return QSize(rows(), 200);
}
int LinearView::rows(const QModelIndex &index) const
{
return model()->rowCount(model()->parent(index));
}
bool LinearView::isIndexHidden(const QModelIndex &index) const
{
return false;
}
#ifndef MODEL_H
#define MODEL_H
#include <QAbstractListModel>
#include <QObject>
#include <qvector.h>
class LinearModel : public QAbstractListModel
{
Q_OBJECT
public:
LinearModel(QObject *parent = 0)
: QAbstractListModel(parent) {}
int rowCount(const QModelIndex &parent = QModelIndex()) const;
QModelIndex index(int row, int column = 0, const QModelIndex &parent = QModelIndex()) const;
QVariant data(const QModelIndex &index, int role) 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:
QVector<int> values;
};
#endif
/*
model.cpp
A simple model that uses a QVector 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 LinearModel::rowCount(const QModelIndex &parent) const
{
Q_USING(parent);
return values.count();
}
/*
Returns an appropriate value for the requested data.
If the view requests an invalid index, an invalid variant is returned.
If a header is requested then we just return the column or row number,
depending on the orientation of the header.
Any valid index that corresponds to a string in the list causes that
string to be returned.
*/
/*!
Returns a model index for other component to use when referencing the
item specified by the given row, column, and type. The parent index
is ignored.
*/
QModelIndex LinearModel::index(int row, int column, const QModelIndex &parent) const
{
if (parent == QModelIndex() && row >= 0 && row < rowCount()
&& column == 0)
return createIndex(row, column, 0);
else
return QModelIndex();
}
QVariant LinearModel::data(const QModelIndex &index, int role) const
{
Q_UNUSED(role);
if (!index.isValid())
return QVariant();
return values.at(index.row());
}
/*!
Returns Qt::ItemIsEditable so that all items in the vector can be edited.
*/
Qt::ItemFlags LinearModel::flags(const QModelIndex &index) const
{
// all items in the model are editable
return QAbstractListModel::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 LinearModel::setData(const QModelIndex &index,
const QVariant &value, int role)
{
if (!index.isValid() || role != Qt::EditRole)
return false;
values.replace(index.row(), value.toInt());
emit dataChanged(index, index);
return true;
}
/*!
Inserts a number of rows into the model at the specified position.
*/
bool LinearModel::insertRows(int position, int rows, const QModelIndex &parent)
{
beginInsertRows(parent, position, position + rows - 1);
values.insert(position, rows, 0);
endInsertRows();
return true;
}
/*!
Removes a number of rows from the model at the specified position.
*/
bool LinearModel::removeRows(int position, int rows, const QModelIndex &parent)
{
beginRemoveRows(QModelIndex(), position, position+rows-1);
values.remove(position, rows);
endRemoveRows();
return true;
}
#ifndef WINDOW_H
#define WINDOW_H
#include <QMainWindow>
#include <QString>
#include <QWidget>
#include "model.h"
#include "view.h"
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow::MainWindow(QWidget *parent = 0);
public slots:
void selectOpenFile();
private:
void setupModelView();
void openFile(const QString &fileName);
LinearModel *model;
LinearView *view;
};
#endif
#include <QAction>
#include <QDataStream>
#include <QMenu>
#include <QMenuBar>
#include <QFile>
#include <QFileDialog>
#include <QListView>
#include "window.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
setWindowTitle("Model/View example");
setupModelView();
QAction *openAction = new QAction(tr("&Open"), this);
QAction *quitAction = new QAction(tr("E&xit"), this);
QMenu *fileMenu = new QMenu(tr("&File"), this);
fileMenu->addAction(openAction);
fileMenu->addAction(quitAction);
menuBar()->addMenu(fileMenu);
connect(openAction, SIGNAL(triggered()), this, SLOT(selectOpenFile()));
connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
setCentralWidget(view);
}
void MainWindow::setupModelView()
{
model = new LinearModel(this);
view = new LinearView(this);
view->setModel(model);
}
void MainWindow::selectOpenFile()
{
QString fileName = QFileDialog::getOpenFileName(this,
tr("Select a file to open"), "", tr("Sound files (*.wav)"));
if (!fileName.isEmpty())
openFile(fileName);
}
void MainWindow::openFile(const QString &fileName)
{
QFile file(fileName);
int length = file.size();
if (file.open(QFile::ReadOnly)) {
model->removeRows(0, model->rowCount());
int rows = (length - 0x2c)/2;
model->insertRows(0, rows);
// Perform some dodgy tricks to extract the data from the file.
QDataStream stream(&file);
stream.setByteOrder(QDataStream::LittleEndian);
Q_INT16 left;
Q_INT16 right;
for (int row = 0; row < rows; ++row) {
QModelIndex index = model->index(row);
stream >> left >> right;
model->setData(index, int(left / 256));
}
}
}
/*
main.cpp
An example of a main window application that used a subclassed model
and view to display data from sound files.
*/
#include <QApplication>
#include "model.h"
#include "view.h"
#include "window.h"
/*!
The main function for the linear model example. This creates and
populates a model with long integers then displays the contents of the
model using a QListView widget.
*/
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MainWindow *window = new MainWindow;
window->show();
return app.exec();
}
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