Drag Drop List Model : Drag Drop « Qt « C++

1. C++
2. Qt
3. Drag Drop

Drag Drop List Model

  
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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of an example program for Qt.
** EDITIONS: NOLIMITS
**
****************************************************************************/

#ifndef MODEL_H
#define MODEL_H

#include <QObject>
#include <QStringListModel>

class DragDropListModel : public QStringListModel
{
    Q_OBJECT

public:
    DragDropListModel(const QStringList &strings, QObject *parent = 0);

    Qt::ItemFlags flags(const QModelIndex &index) const;

    bool dropMimeData(const QMimeData *data, Qt::DropAction action,
                      int row, int column, const QModelIndex &parent);
    QMimeData *mimeData(const QModelIndexList &indexes) const;
    QStringList mimeTypes() const;
    Qt::DropActions supportedDropActions() const;
};

#endif







/*
  model.cpp

  A simple model that uses a QStringList as its data source.
*/

#include <QtGui>

#include "model.h"

DragDropListModel::DragDropListModel(const QStringList &strings,
                                     QObject *parent)
    : QStringListModel(strings, parent)
{
}


bool DragDropListModel::dropMimeData(const QMimeData *data,
    Qt::DropAction action, int row, int column, const QModelIndex &parent)
{
    if (action == Qt::IgnoreAction)
        return true;

    if (!data->hasFormat("application/vnd.text.list"))
        return false;

    if (column > 0)
        return false;
    int beginRow;

    if (row != -1)
        beginRow = row;
    else if (parent.isValid())
        beginRow = parent.row();
    else
        beginRow = rowCount(QModelIndex());
    QByteArray encodedData = data->data("application/vnd.text.list");
    QDataStream stream(&encodedData, QIODevice::ReadOnly);
    QStringList newItems;
    int rows = 0;

    while (!stream.atEnd()) {
        QString text;
        stream >> text;
        newItems << text;
        ++rows;
    }
    insertRows(beginRow, rows, QModelIndex());
    foreach (QString text, newItems) {
        QModelIndex idx = index(beginRow, 0, QModelIndex());
        setData(idx, text);
        beginRow++;
    }

    return true;
}
Qt::ItemFlags DragDropListModel::flags(const QModelIndex &index) const
{
    Qt::ItemFlags defaultFlags = QStringListModel::flags(index);

    if (index.isValid())
        return Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled | defaultFlags;
    else
        return Qt::ItemIsDropEnabled | defaultFlags;
}
QMimeData *DragDropListModel::mimeData(const QModelIndexList &indexes) const
{
    QMimeData *mimeData = new QMimeData();
    QByteArray encodedData;

    QDataStream stream(&encodedData, QIODevice::WriteOnly);

    foreach (QModelIndex index, indexes) {
        if (index.isValid()) {
            QString text = data(index, Qt::DisplayRole).toString();
            stream << text;
        }
    }

    mimeData->setData("application/vnd.text.list", encodedData);
    return mimeData;
}
QStringList DragDropListModel::mimeTypes() const
{
    QStringList types;
    types << "application/vnd.text.list";
    return types;
}
Qt::DropActions DragDropListModel::supportedDropActions() const
{
    return Qt::CopyAction | Qt::MoveAction;
}








#ifndef WINDOW_H
#define WINDOW_H

#include <QMainWindow>

class QListView;

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow();

private:
    void setupListItems();

    QListView *listView;
};

#endif










#include <QtGui>

#include "mainwindow.h"
#include "model.h"

MainWindow::MainWindow()
{
    QMenu *fileMenu = new QMenu(tr("&File"));

    QAction *quitAction = fileMenu->addAction(tr("E&xit"));
    quitAction->setShortcut(tr("Ctrl+Q"));

    menuBar()->addMenu(fileMenu);

//  For convenient quoting:
QListView *listView = new QListView(this);
listView->setSelectionMode(QAbstractItemView::ExtendedSelection);
listView->setDragEnabled(true);
listView->setAcceptDrops(true);
listView->setDropIndicatorShown(true);

    this->listView = listView;

    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));

    setupListItems();

    setCentralWidget(listView);
    setWindowTitle(tr("List View"));
}

void MainWindow::setupListItems()
{
    QStringList items;
    items << tr("Oak") << tr("Fir") << tr("Pine") << tr("Birch") << tr("Hazel")
          << tr("Redwood") << tr("Sycamore") << tr("Chestnut")
          << tr("Mahogany");

    DragDropListModel *model = new DragDropListModel(items, this);
    listView->setModel(model);
}





#include <QtGui>

#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow *window = new MainWindow;
    window->show();
    return app.exec();
}

   
    
  

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