JTextArea中的java AVL树遍历

Question

public class AVLTree
{
   public static String inorderTraversal = " ";

   private static void inorder(AVLNode btree)
    {
       if (btree != null)
       {
         inorder(btree.left);
         inorderTraversal += btree.value + " ";
         inorder(btree.right);
       }
    } 

    /**
       This inorder method is the public interface to
       the private inorder method. It calls the private 
       inorder method and passes it the root of the tree.
    */

    public static void inorder()
    {
        inorder(root);
    }
}

class AVLTreeDemo extends JFrame
implements ActionListener
{

    public void actionPerformed(ActionEvent evt)
    {
        String cmdStr = cmdTextField.getText();
          int size = Integer.parseInt(cmdStr);
        int[] array = new int[size];

        // input validation


        // Random number method
          randNum(array, size);

        // for loop adds numbers to AVL Tree        
        for (int i = 0; i < size; i++)
        {
            int value = array[i];
            avlTree.add(value);
        }
          if (view != null)
                remove(view);
            view = avlTree.getView();            
            add(view);
            pack();
            validate(); 
            cmdResultTextField.setText(" ");

        // inorder method
        AVLTree.inorder();

        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < size; i++)
        {
            sb.append(String.format(" %2d", size)); // Formats right justified
            if ((i + 1) % 10 == 0)
            {
                sb.append(System.lineSeparator()); // Adds a new line after 10 values
            }
        }
        //inorderTextArea.setText(sb.toString(AVLTree.inorderTraversal));

        // display the array in inorder to the inorder text field
        inorderTextArea.setText(AVLTree.inorderTraversal);
    } 

    /**
      The randNum method randomly selects numbers
      in a given range.
      @param array The array.
      @param num The integer numbers.
   */

     public static void randNum(int[] array, int num)
     {                
        Random rand = new Random();

        // Selection sort method
          selectionSort(array);

        // display duplicates
        /*int last = array[0];
        int count = -1;

        for (int i : array)
        {
            if (i == last)
            {
               count++;
               continue;
            }
            System.out.println("Number " + last + " found " + count + " times.");
            count = 1;
            last = i;
         }*/

        for(int i = 0; i < num; i++)
        {
           // display duplicates
           /*if(num == num - 1)
           {
               System.out.print("Duplicate: " + num);
           }*/

           array[i] = rand.nextInt(500);
        }        
    }

    public static void main(String [ ] args)
    {
       AVLTreeDemo atd = new AVLTreeDemo();
    }
}

我试图在JTextArea中的多行上显示AVL树的按序、前序和后序遍历的输出，最好每行显示10个数字。我尝试了我提供的“for”循环，但是我得到了一个编译错误。问题在于inorderTextArea.setText(sb.toString(AVLTree.inorderTraversal));

错误：

AVLTree.java:527: error: no suitable method found for toString(String) inorderTextArea.setText(sb.toString(AVLTree.inorderTraversal)); ^ method StringBuilder.toString() is not applicable (actual and formal argument lists differ in length) method AbstractStringBuilder.toString() is not applicable (actual and formal argument lists differ in length) method Object.toString() is not applicable (actual and formal argument lists differ in length) 1 error

如何重新编写这行代码以使其工作？谢谢你的帮助