为什么我把JButton添加到一个Jpanel中,缺显示不出来呢

主程序TreeView.javapackage aaa;import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Random;import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;public class TreeView extends JFrame {
private JPanel bigPanel = null;
private JPanel northPanel = null;
private MyPanel southPanel = null; private JTextField jTextField = null;
private JButton addBtn = null;
private JButton clearBtn = null; Random random = new Random();

/**
* This method initializes this
*
*/
private void initialize() {
this.setSize(871, 757);
this.setContentPane(getBigPanel()); this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
} /**
* This method initializes jPanel
*
* @return javax.swing.JPanel
*/
private JPanel getBigPanel() {
if (bigPanel == null) {
bigPanel = new JPanel();
bigPanel.setLayout(null);
bigPanel.add(getNorthPanel(), null);
bigPanel.add(getSouthPanel(), null);
}
return bigPanel;
} /**
* This method initializes northPanel
*
* @return javax.swing.JPanel
*/
private JPanel getNorthPanel() {
if (northPanel == null) {
northPanel = new JPanel();
northPanel.setLayout(null);
northPanel.setBounds(new Rectangle(0, 1, 492, 40));
northPanel.setBorder(BorderFactory.createMatteBorder(5, 5, 5, 5, Color.blue));
northPanel.add(getAddBtn(), null);
northPanel.add(getJTextField(), null);
northPanel.add(getClearBtn(), null);
}
return northPanel;
} /**
* This method initializes jButton
*
* @return javax.swing.JButton
*/
private JButton getAddBtn() {
if (addBtn == null) {
addBtn = new JButton();
addBtn.setBounds(new Rectangle(161, 7, 90, 26));
addBtn.setText("Add");
}
addBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
southPanel.bsTree.add(Integer.parseInt(jTextField.getText()));
} catch (Exception e1) {
} finally {
jTextField.setText(new Integer(random.nextInt(999)).toString());
jTextField.requestFocus();
jTextField.selectAll();

repaint();
}
}
});
return addBtn;
} /**
* This method initializes jTextField
*
* @return javax.swing.JTextField
*/
private JTextField getJTextField() {
if (jTextField == null) {
jTextField = new JTextField();
jTextField.setText(new Integer(random.nextInt(999)).toString());
jTextField.selectAll();
jTextField.setBounds(new Rectangle(7, 7, 143, 26));
}
jTextField.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
addBtn.doClick();
}
}
});
return jTextField;
} /**
* This method initializes clearBtn
*
* @return javax.swing.JButton
*/
private JButton getClearBtn() {
if (clearBtn == null) {
clearBtn = new JButton();
clearBtn.setBounds(new Rectangle(393, 9, 90, 23));
clearBtn.setMnemonic(KeyEvent.VK_UNDEFINED);
clearBtn.setText("Clear");
}
clearBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
southPanel.bsTree.clear();
repaint();
}
});
return clearBtn;
} private MyPanel getSouthPanel() {
if (southPanel == null) {
southPanel = new MyPanel(this);
southPanel.setLayout(null);
southPanel.setBounds(new Rectangle(18, 49, 745, 604));
southPanel.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
}
return southPanel;
} public static void main(String[] args) {
TreeView tv = new TreeView();
} public TreeView() {
super("JFrame1");
initialize();
}
} // @jve:decl-index=0:visual-constraint="10,10"

Node.javapackage aaa;import java.awt.Color;
import java.awt.Graphics;import javax.swing.JButton;public class Node extends JButton {
public int x = 0;
public int y = 0;
public static int width = 80;
public static int height = 20;
public Node parent;
public Node left;
public Node right;
public int key; public void draw(Graphics g, MyPanel myPanel) {
if (this.parent != null) {
g.setColor(Color.black);
g.drawLine(this.x + this.width / 2, this.y + this.height / 2, this.parent.x + this.width / 2, this.parent.y + this.height / 2);
}
this.setBounds(this.x, this.y, this.width, this.height);
this.setText(new Integer(this.key).toString());
myPanel.add(this);
} public void setXY(int x, int y) {
this.x = x;
this.y = y;
} public Node(Node parent, Node left, Node right, int key) {
this.parent = parent;
this.left = left;
this.right = right;
this.key = key;
} public String toString() {
StringBuffer str = new StringBuffer();
str.append("            parent:" + (parent == null ? "null" : parent.key) + "\n");
str.append("            key:   " + key + "\n");
str.append("left:  " + (left == null ? "null" : left.key) + "         right: " + (right == null ? "null" : right.key) + "\n");
return str.toString();
}
}

MyPanel.javapackage aaa;import java.awt.Color;
import java.awt.Graphics;
import java.util.ArrayList;import javax.swing.JPanel;public class MyPanel extends JPanel {
/**
* 平衡二叉树
*/
public BinarySearchTree bsTree;
/**
* x += xOffset;
*/
private int x;
/**
* JFrame的引用
*/
private TreeView tv; int xOffset = Node.width / 2;
int yOffset = Node.height * 2; public MyPanel(TreeView tv) {
this.tv = tv;
this.bsTree = new BinarySearchTree();
this.x = 0;
} public void paint(Graphics g) {
// Color c = g.getColor(); ArrayList<Node> list = new ArrayList<Node>(); treeMidWalk(bsTree.root, 0, list); for (int i = 0; i < list.size(); i++) {
Node n = list.get(i);
// g.setColor(Color.magenta);
// g.fillOval(n.x, n.y, DIAMETER, DIAMETER);
// g.setColor(Color.black);
// if (n.parent != null) {
// g.drawLine(n.x + RADIUS, n.y + RADIUS, n.parent.x + RADIUS,
// n.parent.y + RADIUS);
// }
// g.drawString(new Integer(n.key).toString(), n.x + RADIUS, n.y +
// RADIUS);

n.draw(g, this);

} this.x = 0;
this.setBounds(this.getX(), this.getY(), tv.getWidth(), tv.getHeight());
// g.setColor(c);
} public void treeMidWalk(Node root, int level, ArrayList<Node> list) {
int y = level * yOffset;
if (root != null) {
treeMidWalk(root.left, level + 1, list);
list.add(root);
root.setXY(this.x, y);
this.x += xOffset;
treeMidWalk(root.right, level + 1, list);
}
}
}

BinarySearchTree.javapackage aaa;import java.util.ArrayList;public class BinarySearchTree extends Base {// public static void main(String[] args) {
// int[] a = new int[] { 4, 5, 6, 7, 3, 1, 2, 9, 8 };
// BinarySearchTree tree = new BinarySearchTree();
// for (int i = 0; i < a.length; i++) {
// tree.add(a[i]);
// }
// tree.treeMidWalk(tree.root);
// tree.clear();
// System.out.println();
// } public Node root; public BinarySearchTree() {
this.root = null;
} public void clear() {
root = null;
} public void treeMidWalk(Node root) {
if (root != null) {
treeMidWalk(root.left);
System.out.print(" " + root.key);
treeMidWalk(root.right);
}
} public Node search(Node root, int key) {
if (root == null || root.key == key) {
return root;
}
if (key < root.key) {
return search(root.left, key);
} else {
return search(root.right, key);
}
} public Node searchFor(Node root, int key) {
while (root != null) {
if (key == root.key) {
return root;
} else if (key < root.key) {
root = root.left;
} else {
root = root.right;
}
}
return null;
} public void add(int key) {
Node n = this.root;
Node p = this.root;
while (n != null) {
p = n;
if (key <= n.key) {
n = n.left;
} else {
n = n.right;
}
}
Node newNode = new Node(null, null, null, key);
if (p == null) {
this.root = newNode;
} else {
newNode.parent = p;
if (key <= p.key) {
p.left = newNode;
} else {
p.right = newNode;
}
}
} public void stepToRight(ArrayList<Node> nodes, int x) {
for (int i = 0; i < nodes.size(); i++) {
if (nodes.get(i).x >= x) {
nodes.get(i).x += 50;
}
}
} public Node successor(Node n) {
if (n == null) {
return null;
} if (n.right != null) {
return treeMin(n.right);
}
Node p = n.parent;
while (n.parent != null && p.right == n) {
n = p;
p = n.parent;
} return p;
} public Node predecessor(Node n) {
if (n == null) {
return null;
} if (n.left != null) {
return treeMax(n.left);
} Node p = n.parent; while (n.parent != null && n == p.left) {
n = p;
p = n.parent;
} return p;
} public Node treeMin(Node root) {
if (root == null) {
return root;
}
while (root.left != null) {
root = root.left;
}
return root;
} public Node treeMax(Node root) {
if (root == null) {
return root;
}
while (root.right != null) {
root = root.right;
}
return root;
}
}

Base.java
package aaa;public class Base {
public static void swap(int[] a, int x1, int x2) {
int temp;
temp = a[x1];
a[x1] = a[x2];
a[x2] = temp;
} public static double log2(double val) {
return Math.log(val) / Math.log(2);
}

public static void printArr(int[] a) {
for (int i = 0; i < a.length; i++) {
System.out.print(a[i] + " ");
}
System.out.println();
} public static String printNum(int number, int spacePad) {
String s = String.valueOf(number);
StringBuilder sb = new StringBuilder();
int length = s.length();
if (length < spacePad) {
for (int i = 1; i <= spacePad - length; i++) {
sb.append("_");
}
sb.append(s);
return sb.toString();
} else if (length == spacePad) {
return s;
} else {
throw new RuntimeException("spacePad cannot smaller than the length of number");
}
} public static void printTree(int[] a, int spacePad) {
int length = a.length;
int height = (int) (log2(length) + 1);
for (int h = 1; h <= height; h++) {
int firstSpace = (int) (spacePad * (Math.pow(2, height - h) - 1));
StringBuilder sbFirst = new StringBuilder();
for (int i = 0; i < firstSpace; i++) {
sbFirst.append(" ");
}
int intervalSpace = (int) (spacePad * (Math.pow(2, height - h + 1) - 1));
StringBuilder sbInterval = new StringBuilder();
for (int i = 0; i < intervalSpace; i++) {
sbInterval.append(" ");
}

System.out.print(sbFirst);

int start = (int) Math.pow(2, h - 1) - 1;
int end = (int) Math.pow(2, h) - 1;
if (end > length) {
end = length;
}
for (int i = start; i < end; i++) {
System.out.print(printNum(a[i], 2) + sbInterval);
}
System.out.println();
}
}
}

虽然还没解决楼主的问题，我有一点发现，希望对楼主有用。
在node.java的
public void draw(Graphics g, MyPanel myPanel)方法中，如果把myPanel.add(this);放到方法的第一句，当添加的结点比前面的都大时，就会显示该结点。
还有当按下clear按钮后面板并没立即清空。

终于解决问题了
只要将MyPanel.java 的
public void paint(Graphics g)
改为
public void paintComponent(Graphics g)就行。

我找到你程序的问题了，但不我改不了你的代码，你的代码看上去挺乱的，所以问题是你没有把Node加到southPanel中，所以southPanel没法刷新Node，
你必须把每次新增的Node添加到southPanel（southPanel.add(node)）中
这样就不会出现你说的那问题哦！！！小弟出道不到一年，请大家多关照，指教，谢谢哦！！！！

package aaa;import java.util.ArrayList;public class BinarySearchTree extends Base {//    public static void main(String[] args) {
//        int[] a = new int[] { 4, 5, 6, 7, 3, 1, 2, 9, 8 };
//        BinarySearchTree tree = new BinarySearchTree();
//        for (int i = 0; i < a.length; i++) {
//            tree.add(a[i]);
//        }
//        tree.treeMidWalk(tree.root);
//        tree.clear();
//        System.out.println();
//    }    public Node root;////////////////////////////////////////////////////
    private Node newNode;
/////////////////////////////////////////////////////    public BinarySearchTree() {
        this.root = null;
    }    public void clear() {
        root = null;
    }    public void treeMidWalk(Node root) {
        if (root != null) {
            treeMidWalk(root.left);
            System.out.print(" " + root.key);
            treeMidWalk(root.right);
        }
    }    public Node search(Node root, int key) {
        if (root == null || root.key == key) {
            return root;
        }
        if (key < root.key) {
            return search(root.left, key);
        } else {
            return search(root.right, key);
        }
    }    public Node searchFor(Node root, int key) {
        while (root != null) {
            if (key == root.key) {
                return root;
            } else if (key < root.key) {
                root = root.left;
            } else {
                root = root.right;
            }
        }
        return null;
    }    public void add(int key) {
        Node n = this.root;
        Node p = this.root;
        while (n != null) {
            p = n;
            if (key <= n.key) {
                n = n.left;
            } else {
                n = n.right;
            }
        }
/////////////////////////////////////////////////////////
       newNode = new Node(null, null, null, key);
////////////////////////////////////////////////////////
        if (p == null) {
            this.root = newNode;
        } else {
            newNode.parent = p;
            if (key <= p.key) {
                p.left = newNode;
            } else {
                p.right = newNode;
            }
        }
    }    public void stepToRight(ArrayList<Node> nodes, int x) {
        for (int i = 0; i < nodes.size(); i++) {
            if (nodes.get(i).x >= x) {
                nodes.get(i).x += 50;
            }
        }
    }    public Node successor(Node n) {
        if (n == null) {
            return null;
        }        if (n.right != null) {
            return treeMin(n.right);
        }
        Node p = n.parent;
        while (n.parent != null && p.right == n) {
            n = p;
            p = n.parent;
        }        return p;
    }    public Node predecessor(Node n) {
        if (n == null) {
            return null;
        }        if (n.left != null) {
            return treeMax(n.left);
        }        Node p = n.parent;        while (n.parent != null && n == p.left) {
            n = p;
            p = n.parent;
        }        return p;
    }    public Node treeMin(Node root) {
        if (root == null) {
            return root;
        }
        while (root.left != null) {
            root = root.left;
        }
        return root;
    }    public Node treeMax(Node root) {
        if (root == null) {
            return root;
        }
        while (root.right != null) {
            root = root.right;
        }
        return root;
    }
}

我曾写过一个程序，我用一个JLabel加一个图片做背景，结果把其它的组件给遮住了，只要鼠标移到某个组件上，则那个组件就显示出来，
你这个问题也应该是这类问题哦？？！！！

调试易

为什么我把JButton添加到一个Jpanel中,缺显示不出来呢

解决方案 »