doc/src/snippets/draganddrop/dragwidget.cpp
changeset 7 f7bc934e204c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/src/snippets/draganddrop/dragwidget.cpp	Wed Mar 31 11:06:36 2010 +0300
@@ -0,0 +1,154 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtGui>
+
+#include "dragwidget.h"
+
+DragWidget::DragWidget(QWidget *parent)
+    : QFrame(parent)
+{
+    setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
+    dragDropLabel = new QLabel("", this);
+    dragDropLabel->setAlignment(Qt::AlignHCenter);
+
+    QHBoxLayout *layout = new QHBoxLayout(this);
+    layout->addStretch(0);
+    layout->addWidget(dragDropLabel);
+    layout->addStretch(0);
+
+    setAcceptDrops(true);
+}
+
+// Accept all actions, but deal with them separately later.
+//! [0]
+void DragWidget::dragEnterEvent(QDragEnterEvent *event)
+{
+    event->acceptProposedAction();
+}
+//! [0]
+
+//! [1]
+void DragWidget::dropEvent(QDropEvent *event)
+{
+    if (event->source() == this && event->possibleActions() & Qt::MoveAction)
+        return;
+//! [1]
+
+//! [2]
+    if (event->proposedAction() == Qt::MoveAction) {
+        event->acceptProposedAction();
+        // Process the data from the event.
+//! [2]
+        emit dragResult(tr("The data was moved here."));
+//! [3]
+    } else if (event->proposedAction() == Qt::CopyAction) {
+        event->acceptProposedAction();
+        // Process the data from the event.
+//! [3]
+        emit dragResult(tr("The data was copied here."));
+//! [4]
+    } else {
+        // Ignore the drop.
+        return;
+    }
+//! [4]
+    // End of quote
+
+    emit mimeTypes(event->mimeData()->formats());
+    setData(event->mimeData()->formats()[0],
+            event->mimeData()->data(event->mimeData()->formats()[0]));
+//! [5]
+}
+//! [5]
+
+//! [6]
+void DragWidget::mousePressEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton)
+        dragStartPosition = event->pos();
+}
+//! [6]
+
+//! [7]
+void DragWidget::mouseMoveEvent(QMouseEvent *event)
+{
+    if (!(event->buttons() & Qt::LeftButton))
+        return;
+    if ((event->pos() - dragStartPosition).manhattanLength()
+         < QApplication::startDragDistance())
+        return;
+
+    QDrag *drag = new QDrag(this);
+    QMimeData *mimeData = new QMimeData;
+
+    mimeData->setData(mimeType, data);
+    drag->setMimeData(mimeData);
+
+    Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction);
+//! [7]
+
+    switch (dropAction) {
+        case Qt::CopyAction:
+            emit dragResult(tr("The text was copied."));
+            break;
+        case Qt::MoveAction:
+            emit dragResult(tr("The text was moved."));
+            break;
+        default:
+            emit dragResult(tr("Unknown action."));
+            break;
+    }
+//! [8]
+}
+//! [8]
+
+void DragWidget::setData(const QString &mimetype, const QByteArray &newData)
+{
+    mimeType = mimetype;
+    data = QByteArray(newData);
+
+    dragDropLabel->setText(tr("%1 bytes").arg(data.size()));
+
+    QStringList formats;
+    formats << mimetype;
+    emit mimeTypes(formats);
+}