树 - 拖放节点 - 刷新？

我有一个与 smartgwt 树结构相关的问题。 我正在创建一棵树（称为nodesTree）具有来自数据库的值，并且每个节点都设置了一个名称。 例如，我有 4 个节点（数字是节点的名称）：

1
  2
3
  4

for (TreeNode node : nodesTree.getAllNodes())
   System.out.print(node.getName());

Output: 1 2 3 4

如果我将节点 4 拖到节点 1 下（与 2 处于同一级别）

1
  2
  4
3

我想要节点的顺序：1 2 4 3但如果我重复上面的“for”语句，输出将与上面相同：1 2 3 4.

TreeGrid.refreshFields()不起作用。

我正在使用 smartgwt 2.4。

谢谢。

稍后编辑:

该树是手动填充的。我根据从数据库收到的一些值，从代码手动将节点添加到树中。

Tree nodesTree = new Tree();
TreeGrid navTreeGrid = new TreeGrid();
navTreeGrid.setData(nodesTree);
navTreeGrid.setCanReorderRecords(true); 
navTreeGrid.setCanReparentNodes(true);

后来编辑（2011 年 2 月 15 日）：更多代码：

private static final String NAVPATH_ROOT = "/";

// Tree structure
Tree nodesTree = new Tree();
nodesTree.setRootValue(NAVPATH_ROOT);
nodesTree.setModelType(TreeModelType.PARENT);

TreeGrid navTreeGrid = new TreeGrid();
navTreeGrid.setCanReorderRecords(true);
navTreeGrid.setCanReparentNodes(true);
navTreeGrid.setData(nodesTree);

// add first node
TreeNode newNode = new TreeNode();
newNode.setName("a");
nodesTree.add(newNode, NAVPATH_ROOT);

// add the second node
newNode = new TreeNode();
newNode.setName("ab");
nodesTree.add(newNode, NAVPATH_ROOT);

// add the third node to the tree 
newNode = new TreeNode();
newNode.setName("abc");
nodesTree.add(newNode, NAVPATH_ROOT);

navTreeGrid.addDropHandler(new DropHandler()
{
   @Override
   public void onDrop(DropEvent event)
   {
      resetNodesAttributes();

    });

// I want in this method to have the order of nodes after drag&drop action was made.
// for example if I drag& drop node "abc" under "a" I want the method below to post  
// nodes in this order: a  abc  ab
public void resetNodesAttributes(){
    for (TreeNode node : nodesTree.getAllNodes()) {
       System.out.println("---:" + node.getName());
    }
}

稍后编辑:

我添加了一个DataChangedHandler to Tree像这样的小部件：

nodesTree.addDataChangedHandler(new com.smartgwt.client.widgets.tree.DataChangedHandler() 
{
   @Override
   public void onDataChanged(com.smartgwt.client.widgets.tree.DataChangedEvent dataChangedEvent) 
   {
        resetNodesAttributes();
   }
});

它工作正常，但是当我将示例节点“abc”拖放到节点“a”下时，输出为：

a  ab  a  abc  ab  a  abc  ab

所以，似乎该方法resetNodesAttributes它被调用了 3 次 - 我不希望这样 - 我只需要被调用一次。此外，节点的名称有时会发生变化，而且我不希望调用此方法。

稍后编辑（2月18日）:

package de.vogella.gwt.helloworld.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RootPanel;
import com.smartgwt.client.types.TreeModelType;
import com.smartgwt.client.widgets.events.DropEvent;
import com.smartgwt.client.widgets.events.DropHandler;
import com.smartgwt.client.widgets.tree.Tree;
import com.smartgwt.client.widgets.tree.TreeGrid;
import com.smartgwt.client.widgets.tree.TreeNode;

public class HelloGwt implements EntryPoint {

    private static final String NAVPATH_ROOT = "/";
    Tree nodesTree = null;

    @Override
    public void onModuleLoad() {
        // Tree structure
        nodesTree = new Tree();
        nodesTree.setRootValue(NAVPATH_ROOT);
        nodesTree.setModelType(TreeModelType.PARENT);

        TreeGrid navTreeGrid = new TreeGrid();
        navTreeGrid.setCanReorderRecords(true);
        navTreeGrid.setCanReparentNodes(true);
        navTreeGrid.setData(nodesTree);

        // add first node
        TreeNode newNode = new TreeNode();
        newNode.setName("a");
        nodesTree.add(newNode, NAVPATH_ROOT);

        // add the second node
        newNode = new TreeNode();
        newNode.setName("ab");
        nodesTree.add(newNode, NAVPATH_ROOT);

        // add the third node to the tree 
        newNode = new TreeNode();
        newNode.setName("abc");
        nodesTree.add(newNode, NAVPATH_ROOT);

        navTreeGrid.addDropHandler(new DropHandler() {
            @Override
            public void onDrop(DropEvent event) {
                resetNodesAttributes(); 
            }
        });

        RootPanel.get().add(navTreeGrid);
    }

    public void resetNodesAttributes() {
        // here I want to have the new order of nodes after d&d action was made
        for (TreeNode node : nodesTree.getAllNodes()) {
           System.out.println(node.getName());
        }
    }

}

将你的输出包装在DeferredCommand，您将得到正确的输出。

public class HelloGwt implements EntryPoint 
{
  public void onModuleLoad() 
  {
    Tree tree = new Tree();
    tree.setModelType(TreeModelType.PARENT);

    final TreeGrid grid = new TreeGrid();
    grid.setCanReorderRecords(true);
    grid.setCanReparentNodes(true);
    grid.setData(tree);

    tree.add(createNode("a"), tree.getRoot());
    tree.add(createNode("b"), tree.getRoot());
    tree.add(createNode("c"), tree.getRoot());

    grid.addFolderDropHandler(new FolderDropHandler(){

    public void onFolderDrop(FolderDropEvent event)
    {
      DeferredCommand.addCommand(new Command()
      {
        public void execute()
        {
          for (ListGridRecord node : grid.getRecords()) 
            System.out.println(Tree.nodeForRecord(node).getName());
        }});
      }});


    RootPanel.get().add(grid);
  }

  private TreeNode createNode(String name)
  {
    TreeNode node = new TreeNode();
    node.setName(name);
    node.setID(name);
    return node;
  }
}