droparea.cpp Example File | Qt Widgets 5.12.4

Qt 5.12 | Qt Widgets | Drop Site Example | droparea.cpp Example File

Qt 5.12.4 Reference Documentation

# droparea.cpp Example File

draganddrop/dropsite/droparea.cpp

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      #include "droparea.h"

      #include <QDragEnterEvent>
      #include <QMimeData>

      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)
                  text += urlList.at(i).path() + QLatin1Char('\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();
      }