Qt 4.3: droparea.cpp Example File (draganddrop/dropsite/droparea.cpp)

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# droparea.cpp Example File
draganddrop/dropsite/droparea.cpp

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     #include <QtGui>

     #include "droparea.h"

     DropArea::DropArea(QWidget *parent)
         : QLabel(parent)
     {
         setMinimumSize(200, 200);
         setFrameStyle(QFrame::Sunken | QFrame::StyledPanel);
         setAlignment(Qt::AlignCenter);
         setAcceptDrops(true);
         setAutoFillBackground(true);
         clear();
     }

     void DropArea::dragEnterEvent(QDragEnterEvent *event)
     {
         setText(tr("<drop content>"));
         setBackgroundRole(QPalette::Highlight);

         event->acceptProposedAction();
         emit changed(event->mimeData());
     }

     void DropArea::dragMoveEvent(QDragMoveEvent *event)
     {
         event->acceptProposedAction();
     }

     void DropArea::dropEvent(QDropEvent *event)
     {
         const QMimeData *mimeData = event->mimeData();

         if (mimeData->hasImage()) {
             setPixmap(qvariant_cast<QPixmap>(mimeData->imageData()));
         } else if (mimeData->hasHtml()) {
             setText(mimeData->html());
             setTextFormat(Qt::RichText);
         } else if (mimeData->hasText()) {
             setText(mimeData->text());
             setTextFormat(Qt::PlainText);
         } else if (mimeData->hasUrls()) {
             QList<QUrl> urlList = mimeData->urls();
             QString text;
             for (int i = 0; i < urlList.size() && i < 32; ++i) {
                 QString url = urlList.at(i).path();
                 text += url + QString("\n");
             }
             setText(text);
         } else {
             setText(tr("Cannot display data"));
         }

         setBackgroundRole(QPalette::Dark);
         event->acceptProposedAction();
     }

     void DropArea::dragLeaveEvent(QDragLeaveEvent *event)
     {
         clear();
         event->accept();
     }

     void DropArea::clear()
     {
         setText(tr("<drop content>"));
         setBackgroundRole(QPalette::Dark);

         emit changed();
     }