从堆创建JTree

这门课应该能做到。我使用递归允许任意数量的子级别(假设有足够的对象数组和对象来支持树)。

import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

public class TreeBuilder {

    public static void main(final String[] args) {

        // build the list of object arrays
        List<Object[]> objectArrays = new ArrayList<Object[]>();
        Object[] array1 = {9, null, null, null, null, null, null, null};
        Object[] array2 = {8, 6, null, null, null, null, null, null};
        Object[] array3 = {7, 3, 2, 5, null, null, null, null};
        Object[] array4 = {1, 2, null, null, null, null, null, null};
        objectArrays.add(array1);
        objectArrays.add(array2);
        objectArrays.add(array3);
        objectArrays.add(array4);

        // call the method under test
        JTree result = buildTree(objectArrays);

        // print the results
        if(result == null) {
            System.out.println("FAIL: returned null.");
        } else {
            recursePrintTree((DefaultMutableTreeNode)result.getModel().getRoot(), 0);
        }
    }


    public static void recursePrintTree(
            final DefaultMutableTreeNode treeNode,
            final int indentation) {

        // print the indentation spaces
        for(int index = 0; index < indentation; index++) {
            System.out.print("    ");
        }
        // print the value of the node
        System.out.println(treeNode.getUserObject());

        // enumerate the children of the node
        Enumeration enumeration = treeNode.children();
        while(enumeration.hasMoreElements()) {
            DefaultMutableTreeNode child =
                (DefaultMutableTreeNode)enumeration.nextElement();
            recursePrintTree(child, indentation + 1);
        }
    }


    public static JTree buildTree(final List<Object[]> objectArrays) {
        JTree jTree = new JTree();

        DefaultMutableTreeNode node = recurseBuildTree(objectArrays, 0, 0);
        if(node != null) {
            jTree.setModel(new DefaultTreeModel(node));
        }

        return jTree;
    }


    private static DefaultMutableTreeNode recurseBuildTree(
            final List<Object[]> objectArrays,
            final int objectArrayIndex,
            final int itemIndex) {

        DefaultMutableTreeNode node = null;

        if(objectArrayIndex < objectArrays.size()) {
            Object[] objectArray = objectArrays.get(objectArrayIndex);
            if(itemIndex < objectArray.length) {
                Object obj = objectArray[itemIndex];
                if(obj != null) {
                    node = new DefaultMutableTreeNode(obj);

                    DefaultMutableTreeNode childNode = recurseBuildTree(
                        objectArrays, objectArrayIndex + 1, itemIndex * 2);

                    if(childNode != null) {
                        node.add(childNode);
                    }

                    childNode = recurseBuildTree(
                        objectArrays, objectArrayIndex + 1, (itemIndex * 2) + 1);

                    if(childNode != null) {
                        node.add(childNode);
                    }
                }
            }
        }

        return node;
    }

}

结果是:

9
    8
        7
            1
            2
        3
    6
        2
        5