Question

我想要一个展开树，我想要打印到文本区域。它是在控制台中打印，但我决定添加一个GUI，我想将树打印到textArea。

public class Bst<Key extends Comparable<Key>, Value>  {
    private Node root;   

    private class Node {
        private Key phone_number;            
        private Value contact_name;        
        private Node left, right;   
        public Node(Key phone_number, Value contact_name) {
            this.phone_number   = phone_number;
            this.contact_name = contact_name;
        }
    }
    public boolean contains(Key phone_number) {
        return (get(phone_number) != null);
    }

    // return contact_name associated with the given phone_number

    public Value get(Key phone_number) {
        root = splay(root, phone_number);
        int cmp = phone_number.compareTo(root.phone_number);
        if (cmp == 0)
            return root.contact_name;
        else
            return null;
    } 


    public void printTree( )
    {
        if( isEmpty( ) )
            System.out.println( "Empty tree" );
        else
            printTree( root );           
    }

    private void printTree( Node t )
    {
        if ( t.left != null ) 
        {
            System.out.println( "Phone Number:" + t.phone_number.toString( ) + "  Contact Name : " + t.contact_name.toString( ) );
            printTree( t.left );
        } 

        if (t.right != null)
        {
                printTree( t.right );
                System.out.println( "name:" + t.phone_number.toString( ) + "  Number : " + t.contact_name.toString( )  );
        }
    }
 }

目前我的printTree具有void返回类型，如上所示。

如何修改我的代码，以便能够将所有树值和键打印到TextArea。我知道setText（）采用字符串类型，但在这种情况下不起作用（我认为），我怎样才能确保print方法将所有值输出到文本区域？

Answer 1

以下是您需要的代码。请注意，您的no-arg printTree（）方法现在返回一个String，您可以使用该字符串在其他位置打印树。

public class Bst<Key extends Comparable<Key>, Value>  {
    private Node root;   

    private class Node {
        private Key phone_number;            
        private Value contact_name;        
        private Node left, right;   
        public Node(Key phone_number, Value contact_name) {
            this.phone_number   = phone_number;
            this.contact_name = contact_name;
        }
    }
    public boolean contains(Key phone_number) {
        return (get(phone_number) != null);
    }

    // return contact_name associated with the given phone_number

    public Value get(Key phone_number) {
        root = splay(root, phone_number);
        int cmp = phone_number.compareTo(root.phone_number);
        if (cmp == 0)
            return root.contact_name;
        else
            return null;
    } 


    public String printTree( )
    {
        if( isEmpty( ) )
            return "Empty tree";
        else
        {
            StringBuilder sb = new StringBuilder();
            printTree( root, sb );
            return sb.toString();
        }
    }

    private void printTree( Node t, StringBuilder sb )
    {
        if ( t.left != null ) 
        {
            sb.append( "Phone Number:" + t.phone_number.toString( ) + "  Contact Name : " + t.contact_name.toString( ) );
            printTree( t.left, sb );
        } 

        if (t.right != null)
        {
                printTree( t.right, sb );
                sb.append( "name:" + t.phone_number.toString( ) + "  Number : " + t.contact_name.toString( )  );
        }
    }
 }

Answer 2

您可以使用以下代码。实现toString（）允许您忘记从printTree（）获得的任何其他字符串打印。你可以打印出你的物体顺便说一句，如果“Value”和“Key”正在实现toString（），那么就不需要调用它，你可以在带有运算符“+”的字符串中使用它们。

public String toString() 
{
    return printTree();
}

public String printTree( )
{
    String str;
    if( isEmpty( ) )
        str = "Empty tree";
    else
        str += printTree( root );
}

private String printTree( Node t )
{
    String str = "";
    if ( t.left != null ) 
    {
        str += "Phone Number:" + t.phone_number + "  Contact Name : " + t.contact_name + "\n";
        str += printTree( t.left );
    } 
    if (t.right != null)
    {
        str += printTree( t.right );
        str += "name:" + t.phone_number + "  Number : " + t.contact_name + "\n";
    }
    return str;
}

将BST打印到java中的文本区域

2 个答案: