Java 如何将list转换为DefaultMutableTreeNode?
如何将列表转换为DefaultMutableTreeNode 我正在从列表中的数据库获取数据。现在我想把这个列表转换成JTree。我怎么做Java 如何将list转换为DefaultMutableTreeNode?,java,jtree,Java,Jtree,如何将列表转换为DefaultMutableTreeNode 我正在从列表中的数据库获取数据。现在我想把这个列表转换成JTree。我怎么做 public class ExpressionTree extends JFrame implements ActionListener { private JComboBox group; private JLabel groupLabel; Container content; JTree tree; DefaultMutableTreeNod
public class ExpressionTree extends JFrame implements ActionListener {
private JComboBox group;
private JLabel groupLabel;
Container content;
JTree tree;
DefaultMutableTreeNode root, child;
public static void main(String[] args) {
new ExpressionTree();
}
public ExpressionTree() {
super("Creating a Simple JTree");
WindowUtilities.setNativeLookAndFeel();
addWindowListener(new ExitListener());
content = getContentPane();
group = new JComboBox();
groupLabel = new JLabel("GROUP");
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
Set<Integer> set = expressionBuilder.getGroup().keySet();
Iterator<Integer> iterator = set.iterator();
group.addItem("select");
while(iterator.hasNext()){
group.addItem(expressionBuilder.getGroup().get(iterator.next()));
}
content.add(groupLabel);
content.add(group);
group.addActionListener(this);
content.setLayout(new FlowLayout());
root= new DefaultMutableTreeNode("root");
tree = new JTree(root);
content.add(new JScrollPane(tree), BorderLayout.CENTER);
setSize(300, 475);
setVisible(true);
}
public String groupString = null;
public int groupId;
public void actionPerformed(ActionEvent e){
groupString = group.getSelectedItem().toString();
ExpressionBuilder builder=new ExpressionBuilder();
builder.getGroupId(groupString);
//tree.setModel(new NodeTree());.........//what to write over here
//root.add(new NodeTree());
}
}
public class NodeTree extends DefaultMutableTreeNode{
private JTree tree;
DefaultMutableTreeNode top;
public NodeTree(){
ExpressionTree expressionTree= new ExpressionTree();
String groupstring = expressionTree.groupString;
int groupId = expressionTree.groupId;
top = new DefaultMutableTreeNode(groupstring);
tree = new JTree(top);
tree.setEditable(true);
JScrollPane treeView = new JScrollPane(tree);
createNode(top,groupId);
}
public void createNode(DefaultMutableTreeNode top,int group){
DefaultMutableTreeNode expression[] = null;
ExpressionBuilder builder=new ExpressionBuilder();
Object object = (Object)builder.getExpression(group,0);
expression[1] = new DefaultMutableTreeNode(object);
top.add(expression[1]);
expression[1].add(new DefaultMutableTreeNode((Object)builder.getExpression(group,1)));
}
}
假设您正确地从数据库中获取节点名称,并且节点没有层次结构,则可以使用此代码创建树
private JTree createTree(List<String> nodeNames) {
DefaultMutableTreeNode root = new DefaultMutableTreeNode(new Object());
TreeModel model = new DefaultTreeModel(root);
for (int i = 0; i < nodeNames.size(); i++) {
root.add(new DefaultMutableTreeNode(nodeNames.get(i)));
}
JTree tree = new JTree(model);
tree.setRootVisible(false);
return tree;
}
注意:我创建了虚拟节点作为根节点,并使用setRootVisiblefalse。如果您有一个有效的根节点,您可以使用它并删除隐藏根节点的行。列表中的哪些元素来自DB?两者都代表不同的DS。“转换”是什么意思??,这不取决于你的应用程序规范吗?请将源代码添加到你的问题中有一个编辑链接,而不是注释-此处不可读。@JigarJoshi:ya我知道两者都是不同的DS。但我想使用swing以树的形式在数据库中显示数据。当我从数据库中提取数据时,它被提取为字符串。