如何在 JTable 中拖放一行？

drag-and-drop java mouse swing jtable

2022-09-01 07:29:41

如何设置 JTable 以便能够将一行拖动到表中的其他索引。例如，如果我有 5 行，而我想将第 4 行拖到第 2 个位置？

答案 1

以下内容允许对单个拖动的行进行 JTable 重新排序：

  table.setDragEnabled(true);
  table.setDropMode(DropMode.INSERT_ROWS);
  table.setTransferHandler(new TableRowTransferHandler(table));

您的 TableModel 应实现以下操作以允许重新排序：

public interface Reorderable {
   public void reorder(int fromIndex, int toIndex);
}

此 TransferHandler 类处理拖放操作，并在手势完成时调用 TableModel 上的 reorder（）。

/**
 * Handles drag & drop row reordering
 */
public class TableRowTransferHandler extends TransferHandler {
   private final DataFlavor localObjectFlavor = new ActivationDataFlavor(Integer.class, "application/x-java-Integer;class=java.lang.Integer", "Integer Row Index");
   private JTable           table             = null;

   public TableRowTransferHandler(JTable table) {
      this.table = table;
   }

   @Override
   protected Transferable createTransferable(JComponent c) {
      assert (c == table);
      return new DataHandler(new Integer(table.getSelectedRow()), localObjectFlavor.getMimeType());
   }

   @Override
   public boolean canImport(TransferHandler.TransferSupport info) {
      boolean b = info.getComponent() == table && info.isDrop() && info.isDataFlavorSupported(localObjectFlavor);
      table.setCursor(b ? DragSource.DefaultMoveDrop : DragSource.DefaultMoveNoDrop);
      return b;
   }

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

   @Override
   public boolean importData(TransferHandler.TransferSupport info) {
      JTable target = (JTable) info.getComponent();
      JTable.DropLocation dl = (JTable.DropLocation) info.getDropLocation();
      int index = dl.getRow();
      int max = table.getModel().getRowCount();
      if (index < 0 || index > max)
         index = max;
      target.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
      try {
         Integer rowFrom = (Integer) info.getTransferable().getTransferData(localObjectFlavor);
         if (rowFrom != -1 && rowFrom != index) {
            ((Reorderable)table.getModel()).reorder(rowFrom, index);
            if (index > rowFrom)
               index--;
            target.getSelectionModel().addSelectionInterval(index, index);
            return true;
         }
      } catch (Exception e) {
         e.printStackTrace();
      }
      return false;
   }

   @Override
   protected void exportDone(JComponent c, Transferable t, int act) {
      if ((act == TransferHandler.MOVE) || (act == TransferHandler.NONE)) {
         table.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
      }
   }

}

答案 2

请查看 Java 教程的拖放部分。有一些关于如何为实现此目的的示例。JTable