java - JTree 随着 arraylist 的变化动态更新

Question

我寻找答案，但找不到任何东西来解决这个问题。我有两个数组列表，其中包含在用户单击后动态更改的字符串，现在创建将显示一个列表中的元素的 JTree 取决于另一个列表中的某种类型。我有一个问题，因为我总是在列表中添加和删除某些内容，并且需要 JTree 来显示更改。它将正确添加 List 中的所有元素，直到我展开，之后就不可能更新 JTree 的内容，至少对我来说是这样。如果我清空我的列表，它会显示为折叠的，但所有内容仍然显示为展开的，即使它在控制台中给出子计数为 0，如果我向列表中添加某些内容，它会添加它但不会显示它。所以基本上问题是直观地显示JTree的变化。

public class JSelectedTree extends JPanel{
          private JTree selectionTree;
          private DefaultTreeModel treeModel;
          public DefaultMutableTreeNode point;
          public DefaultMutableTreeNode polygon;
          public DefaultMutableTreeNode line;
          public JSelectedTree() {
            initGUI();
          }

          public void initGUI() {
                DefaultMutableTreeNode root = new DefaultMutableTreeNode("root");
                point = new DefaultMutableTreeNode("Point");
                polygon = new DefaultMutableTreeNode("Polygon");
                line = new DefaultMutableTreeNode("Line");
                root.add(point);
                root.add(polygon);
                root.add(line);
                treeModel = new DefaultTreeModel(root);
                selectionTree = new JTree(root);
                selectionTree.setRootVisible(false);
                selectionTree.setShowsRootHandles(false);
                selectionTree.getSelectionModel().setSelectionMode(
                    TreeSelectionModel.SINGLE_TREE_SELECTION);
                JScrollPane scroll = new JScrollPane(selectionTree);
                scroll.setBorder(BorderFactory.createTitledBorder("Selected"));
                setLayout(new BorderLayout());
                add(scroll, BorderLayout.CENTER);
              }
          public void resetTree(){
              if(!MultiSelectTool.selectedObject.isEmpty()){
                  polygon.removeAllChildren();
                  point.removeAllChildren();
                  line.removeAllChildren();
                  treeModel.reload();
                  int n = MultiSelectTool.selectedObject.size();
                  for(int i = 0; i < n; i++){
                      if(MultiSelectTool.selectedCoords.get(i).contains("(((")){
                          DefaultMutableTreeNode child = new DefaultMutableTreeNode(MultiSelectTool.selectedObject.get(i));
                          treeModel.insertNodeInto(child, polygon, polygon.getChildCount());
                      }else if(MultiSelectTool.selectedCoords.get(i).contains("((")){
                          DefaultMutableTreeNode child = new DefaultMutableTreeNode(MultiSelectTool.selectedObject.get(i));
                          treeModel.insertNodeInto(child, line, line.getChildCount());
                      }else{
                          DefaultMutableTreeNode child = new DefaultMutableTreeNode(MultiSelectTool.selectedObject.get(i));
                          treeModel.insertNodeInto(child, point, point.getChildCount());
                      }
                  }
              }else{
                  polygon.removeAllChildren();
                  point.removeAllChildren();
                  line.removeAllChildren();
                  treeModel.reload();
              }
          }
}

Answer 1

尝试使用 MVC 模式，以便可以更新 View :)