如何为 NetBeans Visual Library Scene 启用 java.awt.dnd drop？

Question

我使用带有 ImageIcon 的 JLabel 创建了简单的组件面板。那是调色板项目的代码：

public class TransferableIcon extends JLabel implements Transferable {

  private final Image icon;

  public TransferableIcon(Image image) {
    super(new ImageIcon(image));

    this.icon = image;

    setTransferHandler(ImageTransferHandler.getTransferHandler());
    addMouseListener(new MouseAdapter() {
      @Override
      public void mousePressed(MouseEvent e) {
        JComponent component = (JComponent)e.getSource();
        getTransferHandler().exportAsDrag(component, e, TransferHandler.COPY);
      }
    });
  }

  private static final DataFlavor[] FLAVORS = new DataFlavor[]{ DataFlavor.imageFlavor };

  @Override
  public DataFlavor[] getTransferDataFlavors() {
    return FLAVORS;
  }

  @Override
  public boolean isDataFlavorSupported(DataFlavor flavor) {
    boolean result = false;

    for(DataFlavor dataFlavor : FLAVORS) {
      if(dataFlavor.equals(flavor))
        result = true;
    }

    return result;
  }

  @Override
  public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
    if(!isDataFlavorSupported(flavor))
      throw new UnsupportedFlavorException(flavor);
    else
      return icon;
  }
}

我自己的 TransferHandler class 覆盖了一些方法：

public class ImageTransferHandler extends TransferHandler {
  private static final TransferHandler TRANSFER_HANDLER = new ImageTransferHandler();

  @Override
  public int getSourceActions(JComponent c) {
    return TransferHandler.COPY;
  }

  @Override
  protected Transferable createTransferable(JComponent c) {
    Image image = null;

    if(c instanceof JLabel) {
      JLabel label = (JLabel)c;
      Icon icon = label.getIcon();
      image = ((ImageIcon)icon).getImage();

      return new TransferableIcon(image);
    }
    else
      throw new IllegalArgumentException("Can not transfer such a widget");
  }

  public static TransferHandler getTransferHandler() {
    return TRANSFER_HANDLER;
  }
}

我有一个 Visual Library 场景，通过 scene.createView() 方法添加到 JFrame。我在场景中添加了一个 AcceptAction，创建了我自己的 AcceptProvider，但它的 accept() 方法从未被调用：当我尝试将 TransferableIcon 拖到场景中时，我看到“不允许”光标，但没有任何反应当我将图标放到场景中时。那么，如何启用到场景的拖放？

Answer 1

问题并没有我想的那么复杂。在 AcceptAction class 中我们看到，它仅接受 COPY_OR_MOVE 操作的拖放（以及放下）。因此，在您自己的 TransferHandler class 中，您必须设置完全相同的操作：

@Override
public int getSourceActions(JComponent c) {
  return TransferHandler.COPY_OR_MOVE;
}

就是这样！

如何为 NetBeans Visual Library Scene 启用 java.awt.dnd drop？

How to enable java.awt.dnd drop for NetBeans Visual Library Scene?

java

drag-and-drop

awt

netbeans-platform