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     2 **

     3 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

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     7 ** This file is part of the documentation of the Qt Toolkit.

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    16 ** GNU Lesser General Public License Usage

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    40 ****************************************************************************/

    41 

    42 #include <QtGui>

    43 

    44 #include "dragwidget.h"

    45 

    46 DragWidget::DragWidget(QWidget *parent)

    47     : QFrame(parent)

    48 {

    49     setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);

    50     dragDropLabel = new QLabel("", this);

    51     dragDropLabel->setAlignment(Qt::AlignHCenter);

    52 

    53     QHBoxLayout *layout = new QHBoxLayout(this);

    54     layout->addStretch(0);

    55     layout->addWidget(dragDropLabel);

    56     layout->addStretch(0);

    57 

    58     setAcceptDrops(true);

    59 }

    60 

    61 // Accept all actions, but deal with them separately later.

    62 //! [0]

    63 void DragWidget::dragEnterEvent(QDragEnterEvent *event)

    64 {

    65     event->acceptProposedAction();

    66 }

    67 //! [0]

    68 

    69 //! [1]

    70 void DragWidget::dropEvent(QDropEvent *event)

    71 {

    72     if (event->source() == this && event->possibleActions() & Qt::MoveAction)

    73         return;

    74 //! [1]

    75 

    76 //! [2]

    77     if (event->proposedAction() == Qt::MoveAction) {

    78         event->acceptProposedAction();

    79         // Process the data from the event.

    80 //! [2]

    81         emit dragResult(tr("The data was moved here."));

    82 //! [3]

    83     } else if (event->proposedAction() == Qt::CopyAction) {

    84         event->acceptProposedAction();

    85         // Process the data from the event.

    86 //! [3]

    87         emit dragResult(tr("The data was copied here."));

    88 //! [4]

    89     } else {

    90         // Ignore the drop.

    91         return;

    92     }

    93 //! [4]

    94     // End of quote

    95 

    96     emit mimeTypes(event->mimeData()->formats());

    97     setData(event->mimeData()->formats()[0],

    98             event->mimeData()->data(event->mimeData()->formats()[0]));

    99 //! [5]

   100 }

   101 //! [5]

   102 

   103 //! [6]

   104 void DragWidget::mousePressEvent(QMouseEvent *event)

   105 {

   106     if (event->button() == Qt::LeftButton)

   107         dragStartPosition = event->pos();

   108 }

   109 //! [6]

   110 

   111 //! [7]

   112 void DragWidget::mouseMoveEvent(QMouseEvent *event)

   113 {

   114     if (!(event->buttons() & Qt::LeftButton))

   115         return;

   116     if ((event->pos() - dragStartPosition).manhattanLength()

   117          < QApplication::startDragDistance())

   118         return;

   119 

   120     QDrag *drag = new QDrag(this);

   121     QMimeData *mimeData = new QMimeData;

   122 

   123     mimeData->setData(mimeType, data);

   124     drag->setMimeData(mimeData);

   125 

   126     Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction);

   127 //! [7]

   128 

   129     switch (dropAction) {

   130         case Qt::CopyAction:

   131             emit dragResult(tr("The text was copied."));

   132             break;

   133         case Qt::MoveAction:

   134             emit dragResult(tr("The text was moved."));

   135             break;

   136         default:

   137             emit dragResult(tr("Unknown action."));

   138             break;

   139     }

   140 //! [8]

   141 }

   142 //! [8]

   143 

   144 void DragWidget::setData(const QString &mimetype, const QByteArray &newData)

   145 {

   146     mimeType = mimetype;

   147     data = QByteArray(newData);

   148 

   149     dragDropLabel->setText(tr("%1 bytes").arg(data.size()));

   150 

   151     QStringList formats;

   152     formats << mimetype;

   153     emit mimeTypes(formats);

   154 }