java - JTable 拖放

Question

我正在尝试实现 JTable 拖放，我已经能够根据此问题( How do I drag and drop a row in a JTable? )中提供的解决方案使其大部分工作，并且此问题( Moving rows in JTable )稍微调整为我的需求。

我也遇到的问题是，尽管使用像此处找到的那样的 TableModel ( Moving rows in JTable )，但它在大多数情况下都可以正常工作，例如拖动三行 JTable，将第一行拖动到第二行工作正常，例如将第一行拖动到第三行下方的底部会导致 ArrayIndexOutOfBoundsException 并且该行消失。错误发生在以下行: getDataVector().add(to, o);

来自 Moving rows in JTable 的以下代码会出现此问题:

public class ReorderableTableModel extends DefaultTableModel implements Reorderable {
    public void reorder(int from, int to) {
         Object o = getDataVector().remove(from);
         getDataVector().add(to, o);
         fireTableDataChanged();
    }
}

亚伦似乎也对这个问题给出了一个答案，解释为什么它可能不起作用: Moving rows in JTable尽管我不确定如何将亚伦的答案应用到我的场景中。

堆栈跟踪是:

java.lang.ArrayIndexOutOfBoundsException: 2 > 1
    at java.util.Vector.insertElementAt(Vector.java:598)
    at java.util.Vector.add(Vector.java:814)
    at com.testproject.test.table.TableModel.reorder(TableModel.java:25)
    at com.testproject.test.table.TableRowTransferHandler.importData(TableRowTransferHandler.java:49)
    at javax.swing.TransferHandler$DropHandler.drop(TransferHandler.java:1544)
    at java.awt.dnd.DropTarget.drop(DropTarget.java:455)
    at javax.swing.TransferHandler$SwingDropTarget.drop(TransferHandler.java:1282)
    at sun.awt.dnd.SunDropTargetContextPeer.processDropMessage(SunDropTargetContextPeer.java:538)
    at sun.lwawt.macosx.CDropTargetContextPeer.processDropMessage(CDropTargetContextPeer.java:143)
    at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchDropEvent(SunDropTargetContextPeer.java:852)
    at sun.awt.dnd.SunDropTargetContextPeer$EventDispatcher.dispatchEvent(SunDropTargetContextPeer.java:776)
    at sun.awt.dnd.SunDropTargetEvent.dispatch(SunDropTargetEvent.java:48)
    at java.awt.Component.dispatchEventImpl(Component.java:4746)
    at java.awt.Container.dispatchEventImpl(Container.java:2294)
    at java.awt.Component.dispatchEvent(Component.java:4713)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
    at java.awt.LightweightDispatcher.processDropTargetEvent(Container.java:4599)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4461)
    at java.awt.Container.dispatchEventImpl(Container.java:2280)
    at java.awt.Window.dispatchEventImpl(Window.java:2750)
    at java.awt.Component.dispatchEvent(Component.java:4713)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

我已尝试解决此问题，但无法解决，解决此问题的最佳方法是什么？

Answer 1

由于您已从 Vector 中删除了一个元素，因此您应该考虑将某些索引变为index-=1；

<小时/>

解决方案

public void reorder(int from, int to) {
     Object o = getDataVector().remove(from);
     getDataVector().add(from>to?to:to-1, o);
     fireTableDataChanged();
}

检查from的索引是否大于to。如果是这样，那么我们就知道 to 的索引没有改变，如果没有改变，则通过将索引删除 1 来改变它。