按钮前景色设置

Question

import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.applet.*;
public class NewJApplet1 extends JApplet {   
    private JButton btn1,btn2,btn3,btn4,btn5; 
    private JTextField tf;
    private JLabel l1,l2;
    private JPanel pane,panel;
    private JPanel p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15;
    private JButton[]btn = new JButton[60];
    private JLabel []la = new JLabel[60];
    private JLabel []l = new JLabel[60];
    Box q1=Box.createHorizontalBox();
    Box q2=Box.createHorizontalBox();
    Box w1=Box.createVerticalBox();
    Box q3=Box.createHorizontalBox();
    private int n=60;
    public void init(){
       pane = new JPanel(); 
       btn1 = new JButton("新建");
       btn2 = new JButton("添加");
       btn3 = new JButton("插入");
       btn4 = new JButton("删除");
       btn5 = new JButton("查找");
       l1 = new JLabel("输入整数"); 
       l1.setFont(new Font("Dialog",Font.BOLD,14)); 
       tf = new JTextField(6);
       tf.setBorder(BorderFactory.createLineBorder(Color.PINK));
       q1.add(btn1); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn2); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn3); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn4); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn5);
       q1.add(Box.createHorizontalStrut(10));
       q1.add(l1); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(tf);
       l2 = new JLabel("Press any button",JLabel.CENTER);
       q2.add(l2);
       w1.add(q1);
       w1.add(Box.createVerticalStrut(10));
       w1.add(q2);
       pane=new JPanel();
       pane.add(w1);  
        p1 = new JPanel();
        p2 = new JPanel();
        p3 = new JPanel();
        p4 = new JPanel();
        p5 = new JPanel(); 
        p6 = new JPanel(); 
        p7 = new JPanel();
        p8 = new JPanel();
        p9 = new JPanel();
        p10 = new JPanel();
        p11 = new JPanel(); 
        p12 = new JPanel(); 
        p13 = new JPanel();
        p14 = new JPanel(); 
        p15 = new JPanel();
       p1.setLayout(new GridLayout(12,0));
       p2.setLayout(new GridLayout(12,0));
       p3.setLayout(new GridLayout(12,0));
       p4.setLayout(new GridLayout(12,0));
       p5.setLayout(new GridLayout(12,0));
       p6.setLayout(new GridLayout(12,0));
       p7.setLayout(new GridLayout(12,0));
       p8.setLayout(new GridLayout(12,0));
       p9.setLayout(new GridLayout(12,0));
       p10.setLayout(new GridLayout(12,0));
       p11.setLayout(new GridLayout(12,0));
       p12.setLayout(new GridLayout(12,0));
       p13.setLayout(new GridLayout(12,0));
       p14.setLayout(new GridLayout(12,0));
       p15.setLayout(new GridLayout(12,0));
       for(int i=0;i<12;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p1.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p2.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p3.add(label);
       }
       for(int i=12;i<24;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p4.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p5.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p6.add(label);
       }
       for(int i=24;i<36;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p7.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p8.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p9.add(label);
       }
       for(int i=36;i<48;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p10.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p11.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p12.add(label);
       }
       for(int i=48;i<60;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p13.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p14.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p15.add(label);
       }
       q3.add(p1);q3.add(p2);q3.add(p3);q3.add(Box.createHorizontalStrut(10));
       q3.add(p4);q3.add(p5);q3.add(p6);q3.add(Box.createHorizontalStrut(10));
       q3.add(p7);q3.add(p8);q3.add(p9);q3.add(Box.createHorizontalStrut(10));
       q3.add(p10);q3.add(p11);q3.add(p12);q3.add(Box.createHorizontalStrut(10));
       q3.add(p13);q3.add(p14);q3.add(p15);
       panel=new JPanel(new FlowLayout(FlowLayout.LEFT));
       panel.add(q3);
       Container cp=getContentPane(); 
       cp.setBackground(Color.GRAY);
       cp.setLayout(new BorderLayout()); 
       cp.add(pane,BorderLayout.NORTH);  
       cp.add(panel,BorderLayout.CENTER);
       setSize(520,340);
       JSplitPane split;
       split=new JSplitPane(JSplitPane.VERTICAL_SPLIT, pane,panel);
       pane.setBorder(BorderFactory.createLineBorder(Color.PINK));
       panel.setBorder(BorderFactory.createLineBorder(Color.PINK));
       cp.add(split);
       split.setDividerLocation(0.8);
       split.setOneTouchExpandable(true);
       split.setDividerSize(8);
       l[0].setVisible(true);
        for(int i=0;i<30;i++)
       {
         Random r=new Random();
         int t=r.nextInt(999);
         add(t);     
        
       }     }
    public void add(int key) {   
    int  h=key%n;
    if(btn[h].getLabel().equals(null))
    {   
       btn[h].setLabel(Integer.toString(key));
    }
    else{
    int a=1;
    h=(h+a)%n;
    while(!(btn[h].getLabel().equals("")))
    h=(h+a)%n;
    btn[h].setLabel(String.valueOf(key));
      //btn[n].setForeground(Color.BLUE);
        }    
    }}

Answer 1

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.Random;import javax.swing.AbstractButton;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.ButtonModel;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import javax.swing.JTextField;
import javax.swing.plaf.basic.BasicButtonUI;import sun.swing.SwingUtilities2;public class NewJApplet1 extends JApplet {
    private JButton btn1, btn2, btn3, btn4, btn5;    private JTextField tf;    private JLabel l1, l2;    private JPanel pane, panel;    private JPanel p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15;    private JButton[] btn = new JButton[60];    private JLabel[] la = new JLabel[60];    private JLabel[] l = new JLabel[60];    Box q1 = Box.createHorizontalBox();    Box q2 = Box.createHorizontalBox();    Box w1 = Box.createVerticalBox();    Box q3 = Box.createHorizontalBox();    private int n = 60;    public void init() {
        pane = new JPanel();
        btn1 = new JButton("新建");
        btn2 = new JButton("添加");
        btn3 = new JButton("插入");
        btn4 = new JButton("删除");
        btn5 = new JButton("查找");
        l1 = new JLabel("输入整数");
        l1.setFont(new Font("Dialog", Font.BOLD, 14));
        tf = new JTextField(6);
        tf.setBorder(BorderFactory.createLineBorder(Color.PINK));
        q1.add(btn1);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(btn2);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(btn3);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(btn4);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(btn5);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(l1);
        q1.add(Box.createHorizontalStrut(10));
        q1.add(tf);
        l2 = new JLabel("Press any button", JLabel.CENTER);
        q2.add(l2);
        w1.add(q1);
        w1.add(Box.createVerticalStrut(10));
        w1.add(q2);
        pane = new JPanel();
        pane.add(w1);
        p1 = new JPanel();
        p2 = new JPanel();
        p3 = new JPanel();
        p4 = new JPanel();
        p5 = new JPanel();
        p6 = new JPanel();
        p7 = new JPanel();
        p8 = new JPanel();
        p9 = new JPanel();
        p10 = new JPanel();
        p11 = new JPanel();
        p12 = new JPanel();
        p13 = new JPanel();
        p14 = new JPanel();
        p15 = new JPanel();

Answer 2

p1.setLayout(new GridLayout(12, 0));
        p2.setLayout(new GridLayout(12, 0));
        p3.setLayout(new GridLayout(12, 0));
        p4.setLayout(new GridLayout(12, 0));
        p5.setLayout(new GridLayout(12, 0));
        p6.setLayout(new GridLayout(12, 0));
        p7.setLayout(new GridLayout(12, 0));
        p8.setLayout(new GridLayout(12, 0));
        p9.setLayout(new GridLayout(12, 0));
        p10.setLayout(new GridLayout(12, 0));
        p11.setLayout(new GridLayout(12, 0));
        p12.setLayout(new GridLayout(12, 0));
        p13.setLayout(new GridLayout(12, 0));
        p14.setLayout(new GridLayout(12, 0));
        p15.setLayout(new GridLayout(12, 0));
        for (int i = 0; i < 12; i++) {
            JLabel labe = new JLabel("" + i);
            la[i] = labe;
            p1.add(labe);
            JButton button = new JButton();
            button.setPreferredSize(new Dimension(65, 21));
            btn[i] = button;
            btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
            p2.add(button);
            button.setEnabled(false);
            JLabel label = new JLabel("←");
            l[i] = label;
            label.setForeground(Color.RED);
            label.setVisible(false);
            p3.add(label);
        }
        for (int i = 12; i < 24; i++) {
            JLabel labe = new JLabel("" + i);
            la[i] = labe;
            p4.add(labe);
            JButton button = new JButton();
            button.setPreferredSize(new Dimension(65, 21));
            btn[i] = button;
            btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
            p5.add(button);
            button.setEnabled(false);
            JLabel label = new JLabel("←");
            l[i] = label;
            label.setForeground(Color.RED);
            label.setVisible(false);
            p6.add(label);
        }
        for (int i = 24; i < 36; i++) {
            JLabel labe = new JLabel("" + i);
            la[i] = labe;
            p7.add(labe);
            JButton button = new JButton();
            button.setPreferredSize(new Dimension(65, 21));
            btn[i] = button;
            btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
            p8.add(button);
            button.setEnabled(false);
            JLabel label = new JLabel("←");
            l[i] = label;
            label.setForeground(Color.RED);
            label.setVisible(false);
            p9.add(label);
        }
        for (int i = 36; i < 48; i++) {
            JLabel labe = new JLabel("" + i);
            la[i] = labe;
            p10.add(labe);
            JButton button = new JButton();
            button.setPreferredSize(new Dimension(65, 21));
            btn[i] = button;
            btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
            p11.add(button);
            button.setEnabled(false);
            JLabel label = new JLabel("←");
            l[i] = label;
            label.setForeground(Color.RED);
            label.setVisible(false);
            p12.add(label);
        }
        for (int i = 48; i < 60; i++) {
            JLabel labe = new JLabel("" + i);
            la[i] = labe;
            p13.add(labe);
            JButton button = new JButton();
            button.setForeground(Color.RED);
            button.setUI(new BtnUI());
            button.setPreferredSize(new Dimension(65, 21));
            btn[i] = button;
            btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
            p14.add(button);
            button.setEnabled(false);
            JLabel label = new JLabel("←");
            l[i] = label;
            label.setForeground(Color.RED);
            label.setVisible(false);
            p15.add(label);
        }
        q3.add(p1);
        q3.add(p2);
        q3.add(p3);
        q3.add(Box.createHorizontalStrut(10));
        q3.add(p4);
        q3.add(p5);
        q3.add(p6);
        q3.add(Box.createHorizontalStrut(10));
        q3.add(p7);
        q3.add(p8);
        q3.add(p9);
        q3.add(Box.createHorizontalStrut(10));
        q3.add(p10);
        q3.add(p11);
        q3.add(p12);
        q3.add(Box.createHorizontalStrut(10));
        q3.add(p13);
        q3.add(p14);
        q3.add(p15);
        panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        panel.add(q3);
        Container cp = getContentPane();
        cp.setBackground(Color.GRAY);
        cp.setLayout(new BorderLayout());
        cp.add(pane, BorderLayout.NORTH);
        cp.add(panel, BorderLayout.CENTER);
        setSize(520, 340);
        JSplitPane split;
        split = new JSplitPane(JSplitPane.VERTICAL_SPLIT, pane, panel);
        pane.setBorder(BorderFactory.createLineBorder(Color.PINK));
        panel.setBorder(BorderFactory.createLineBorder(Color.PINK));
        cp.add(split);
        split.setDividerLocation(0.8);
        split.setOneTouchExpandable(true);
        split.setDividerSize(8);
        l[0].setVisible(true);
        for (int i = 0; i < 30; i++) {
            Random r = new Random();
            int t = r.nextInt(999);
            add(t);        }    }    private class BtnUI extends BasicButtonUI {
        protected void paintText(Graphics g, JComponent c, Rectangle textRect, String text) {
            AbstractButton b = (AbstractButton) c;
            ButtonModel model = b.getModel();
            FontMetrics fm = SwingUtilities2.getFontMetrics(c, g);
            int mnemonicIndex = b.getDisplayedMnemonicIndex();            /* Draw the Text */
            if (model.isEnabled()) {
                /** * paint the text normally */
                g.setColor(b.getForeground());
                SwingUtilities2.drawStringUnderlineCharAt(c, g, text, mnemonicIndex, textRect.x
                    + getTextShiftOffset(), textRect.y + fm.getAscent() + getTextShiftOffset());
            } else {
                /** * paint the text disabled ** */
                g.setColor(b.getForeground().brighter());
                SwingUtilities2.drawStringUnderlineCharAt(
                    c,
                    g,
                    text,
                    mnemonicIndex,
                    textRect.x,
                    textRect.y + fm.getAscent());
                g.setColor(b.getForeground().darker());
                SwingUtilities2.drawStringUnderlineCharAt(
                    c,
                    g,
                    text,
                    mnemonicIndex,
                    textRect.x - 1,
                    textRect.y + fm.getAscent() - 1);
            }
        }
    }    public void add(int key) {
        int h = key % n;
        if (btn[h].getLabel().equals(null)) {
            btn[h].setLabel(Integer.toString(key));
        } else {
            int a = 1;
            h = (h + a) % n;
            while (!(btn[h].getLabel().equals("")))
                h = (h + a) % n;
            btn[h].setLabel(String.valueOf(key));
            // btn[n].setForeground(Color.BLUE);
        }
    }
}

Answer 3

import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.applet.*;
public class NewJApplet extends JApplet implements ActionListener{   
    private JButton btn1,btn2,btn3,btn4,btn5; 
    private JTextField tf;
    private JLabel l1,l2;
    private JPanel pane,panel;
    private JPanel p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15;
    private JButton[]btn = new JButton[60];
    private JLabel []la = new JLabel[60];
    private JLabel []l = new JLabel[60];
    Box q1=Box.createHorizontalBox();
    Box q2=Box.createHorizontalBox();
    Box w1=Box.createVerticalBox();
    Box q3=Box.createHorizontalBox();
    private static int c1=0,c2=0,c3=0,c4=0,c5=0;
    private int i=0,h=0,n=60;
    public void init(){
       pane = new JPanel(); 
       btn1 = new JButton("新建");
       btn2 = new JButton("添加");
       btn3 = new JButton("插入");
       btn4 = new JButton("删除");
       btn5 = new JButton("查找");
       btn1.addActionListener(this);
       btn2.addActionListener(this);
       btn3.addActionListener(this);
       btn4.addActionListener(this);
       btn5.addActionListener(this);
       l1 = new JLabel("输入整数"); 
       l1.setFont(new Font("Dialog",Font.BOLD,14)); 
       tf = new JTextField(6);
       tf.setBorder(BorderFactory.createLineBorder(Color.PINK));
       q1.add(btn1); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn2); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn3); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn4); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(btn5);
       q1.add(Box.createHorizontalStrut(10));
       q1.add(l1); 
       q1.add(Box.createHorizontalStrut(10));
       q1.add(tf);
       l2 = new JLabel("Press any button",JLabel.CENTER);
       q2.add(l2);
       w1.add(q1);
       w1.add(Box.createVerticalStrut(10));
       w1.add(q2);
       pane=new JPanel();
       pane.add(w1);  
        p1 = new JPanel();
        p2 = new JPanel();
        p3 = new JPanel();
        p4 = new JPanel();
        p5 = new JPanel(); 
        p6 = new JPanel(); 
        p7 = new JPanel();
        p8 = new JPanel();
        p9 = new JPanel();
        p10 = new JPanel();
        p11 = new JPanel(); 
        p12 = new JPanel(); 
        p13 = new JPanel();
        p14 = new JPanel(); 
        p15 = new JPanel();
       p1.setLayout(new GridLayout(12,0));
       p2.setLayout(new GridLayout(12,0));
       p3.setLayout(new GridLayout(12,0));
       p4.setLayout(new GridLayout(12,0));
       p5.setLayout(new GridLayout(12,0));
       p6.setLayout(new GridLayout(12,0));
       p7.setLayout(new GridLayout(12,0));
       p8.setLayout(new GridLayout(12,0));
       p9.setLayout(new GridLayout(12,0));
       p10.setLayout(new GridLayout(12,0));
       p11.setLayout(new GridLayout(12,0));
       p12.setLayout(new GridLayout(12,0));
       p13.setLayout(new GridLayout(12,0));
       p14.setLayout(new GridLayout(12,0));
       p15.setLayout(new GridLayout(12,0));
       for(int i=0;i<12;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p1.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p2.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p3.add(label);
       }
       for(int i=12;i<24;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p4.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p5.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p6.add(label);
       }
       for(int i=24;i<36;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p7.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p8.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p9.add(label);
       }
       for(int i=36;i<48;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p10.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p11.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p12.add(label);
       }
       for(int i=48;i<60;i++)
       {  
          JLabel labe = new JLabel(""+i);
          la[i]=labe;
          p13.add(labe);
          JButton button = new JButton();
          button.setPreferredSize(new Dimension(65,21));
          btn[i]=button;
          btn[i].setBorder(BorderFactory.createLineBorder(Color.PINK));
          p14.add(button);
          button.setEnabled(false);
          JLabel label = new JLabel("←");
          l[i]=label;
          label.setForeground(Color.RED);
          label.setVisible(false);
          p15.add(label);
       }
       q3.add(p1);q3.add(p2);q3.add(p3);q3.add(Box.createHorizontalStrut(10));
       q3.add(p4);q3.add(p5);q3.add(p6);q3.add(Box.createHorizontalStrut(10));
       q3.add(p7);q3.add(p8);q3.add(p9);q3.add(Box.createHorizontalStrut(10));
       q3.add(p10);q3.add(p11);q3.add(p12);q3.add(Box.createHorizontalStrut(10));
       q3.add(p13);q3.add(p14);q3.add(p15);
       panel=new JPanel(new FlowLayout(FlowLayout.LEFT));
       panel.add(q3);
       Container cp=getContentPane(); 
       cp.setBackground(Color.GRAY);
       cp.setLayout(new BorderLayout()); 
       cp.add(pane,BorderLayout.NORTH);  
       cp.add(panel,BorderLayout.CENTER);
       setSize(520,340);
       JSplitPane split;
       split=new JSplitPane(JSplitPane.VERTICAL_SPLIT, pane,panel);
       pane.setBorder(BorderFactory.createLineBorder(Color.PINK));
       panel.setBorder(BorderFactory.createLineBorder(Color.PINK));
       cp.add(split);
       split.setDividerLocation(0.8);
       split.setOneTouchExpandable(true);
       split.setDividerSize(8);
       l[0].setVisible(true);        for(int i=0;i<30;i++)
       {
         Random r=new Random();
         int t=r.nextInt(999);
         add(t);     
       } 
    }
    public void add(int key) {  
    Random f=new Random();
    int R=f.nextInt(255);
    int G=f.nextInt(255);
    int B=f.nextInt(255);
    int  h=key%n;
    if(btn[h].getLabel().equals(null))
    {   
       btn[h].setLabel(Integer.toString(key));
    }
    else{
    int a=1;
    h=(h+a)%n;
    while(!(btn[h].getLabel().equals("")))
    h=(h+a)%n;
    btn[h].setLabel(String.valueOf(key));
    btn[h].setBackground(new Color(R,G,B));
        }    
    }

Answer 4

public void  新建()
    {  
       c1++;
    if(c1==1)
        l2.setText("Enter size of array to create");
    if(c1==2){
            if(tf.getText().equals("")||(Integer.parseInt(tf.getText())>60)||(Integer.parseInt(tf.getText())<0))
            {
            l2.setText("ERROR:use size between 0 and 60");
            c1=0;
            }
           else 
             l2.setText("Will create empty array with "+tf.getText()+" cells");
             }
    if(c1==3){
        l2.setText("New array created; total item=0");
        n=Integer.parseInt(tf.getText());
        for(int k=0;k<n;k++)
        {
        l[0].setVisible(true);
        btn[k].setVisible(true);
        la[k].setVisible(true);
        btn[k].setLabel("");
        btn[k].setBackground(Color.WHITE);
        }
        for(int k=n;k<60;k++)
        {
        l[k].setVisible(false);
        btn[k].setVisible(false);
        la[k].setVisible(false);
        }      
     }
 if(c1==4)
   {
    l2.setText("Press any button");
    c1=0;
    }    
  }
    public void 添加()
    {    
       c2++;
    if(c2==1)
        l2.setText("Enter number of item to fill in");  
    if(c2==2)
    {    
        int y=0,b=0;        
         while(btn[y].getLabel()=="")
         {  
             y++;   b++;}
        if(tf.getText().equals("")||(Integer.parseInt(tf.getText())>b)||(Integer.parseInt(tf.getText())<0))
        {
            l2.setText("ERROR: fill between 0 and "+ b +" items");
            c2=0;
        }
         else 
             l2.setText("Will fill in "+tf.getText()+" items");  
       
    }
    if(c2==3)
    {
    l2.setText("Fill completed; total items= "+tf.getText());
    int t=Integer.parseInt(tf.getText());
    for(int i=0;i<t;i++){
    Random ran=new Random();
    int r=ran.nextInt(999);
    add(r);  
    }
    }       
    if(c2==4)
    {    
    l2.setText("Press any button");
    c2=0;
     for(int i=0;i<n;i++)
     {btn[i].setLabel(""); 
     btn[i].setBackground(Color.WHITE);}
    }
 }
    public void 插入()
    {
       c3++;
   int k=0,j=0,q=0;
  if(c3==1){
        l2.setText("Enter key of item to insert");i=0;
           }
    if(c3==2){
        for(j=0;j<n;j++)
        if((!(btn[j].getLabel().equals("")))&&(!(btn[j].getLabel().equals("*Del*"))))
            k++;
        if(k==n){
            l2.setText("CANNT INSERT: array is full");
            c3=0;
        }
        else  if((tf.getText().equals(""))||(Integer.parseInt(tf.getText())>999)||(Integer.parseInt(tf.getText())<0)){
            l2.setText("CANNNT INSERT: need key between 0 and 999");
            c3=0;
        }
         else 
             l2.setText("Will insert item with key  "+tf.getText());              
    }
if(c3==3){ 
    i++;
int hashMax=n; int key=Integer.parseInt(tf.getText());
if(i==1)
     h=key % hashMax;
if(btn[h].getLabel().equals("")||btn[h].getLabel().equals("*Del*")){
   btn[h].setLabel(String.valueOf(key));
   for(q=0;q<n;q++)                                                                                                                                                
       l[q].setVisible(false);
   l[0].setVisible(true);
   l2.setText("Inserted item with key  "+key+"  at index "+h);
   l[0].setVisible(false);
   l[h].setVisible(true);
}
else{
    c3--;
    if(i==1){
         for(q=0;q<n;q++)
            l[q].setVisible(false);
       l2.setText("Cell  "+key+"  occupied; goning to next cell");
       l[h].setVisible(true);
    }
    else{
        for(q=0;q<n;q++)
            l[q].setVisible(false);
        l2.setText("Searching for unoccupied cell; step was  "+(i-1));
        l[h].setVisible(true);
    }
    int a=1;
    h=(h+a)%hashMax;  
}
}
if(c3==4){
    int r=0;
for(i=0;i<n;i++)
    if((!(btn[i].getLabel().equals("")))&&(!(btn[i].getLabel().equals("*Del*"))))
        r++;
    l2.setText("Insert completed; total item = "+r);
    for(q=0;q<n;q++)
            l[q].setVisible(false);
    l[0].setVisible(true);
    c3=0;
}
}
    public void 删除()
    {   
       c4++;int q=0;
    if(c4==1){
        l2.setText("Enter key of item to delete");i=0;
    }
    if(c4==2){
        if(tf.getText().equals("")){
            l2.setText("ERROR: use key between 0 and 999");
            c4=0;
        }
         else {
             int key=Integer.parseInt(tf.getText());
             h=key%n;
              for(q=0;q<n;q++)
            l[q].setVisible(false);
             l2.setText("Looking for item with key  "+tf.getText()+"  at index  "+h);
             l[h].setVisible(true);
         }
    }
 if(c4==3){
     i++;
     if(btn[h].getLabel().equals(tf.getText())){
          for(q=0;q<n;q++)
            l[q].setVisible(false);
          l[h].setVisible(true);
     l2.setText("Have found item with key  "+tf.getText()+"  at index  "+h);
     }
     else if(btn[h].getLabel().equals("")){
          for(q=0;q<n;q++)
            l[q].setVisible(false);
          l[h].setVisible(true);
         l2.setText("Cannt locate item with key  "+tf.getText());
         for(q=0;q<n;q++)
            l[q].setVisible(false);
          l[0].setVisible(true);
         c4=0;
     }
     else{
         c4--;
       if(i==1)
           l2.setText("No match: will start probe");         
       else{
            for(q=0;q<n;q++)
            l[q].setVisible(false);
           l2.setText("Checking next cell; step was  "+(i-1));
        l[h].setVisible(true);
        if(i==n){           
         l2.setText("Cannt locate item with key  "+tf.getText());         
        }
        if(i==(n+1)){
         for(q=0;q<n;q++)
            l[q].setVisible(false);
            l[0].setVisible(true);
          l2.setText("Press any Button");
          c4=0;
        }
       }
         int a=1;
         h=(h+a)%n;
     } 
 }
 if(c4==4){
      btn[h].setLabel("*Del*");
     int r=0;
for(i=0;i<n;i++)
    if((!(btn[i].getLabel().equals("")))&&(!(btn[i].getLabel().equals("*Del*"))))
        r++;      
    l2.setText("Deleted item with key  "+tf.getText()+" ; total item = "+r);   
 }
 if(c4==5){
 l2.setText("Press any button");
  for(q=0;q<n;q++)
        l[q].setVisible(false);
 l[0].setVisible(true);
 c4=0;
 }
}

Answer 5

  public void 查找()
    {
       c5++;
       if(c5==1)
        {
          l2.setText("Enter key of item to find");
        }
       if(c5==2)
       {
            if(tf.getText().equals("")||(Integer.parseInt(tf.getText())>999)||(Integer.parseInt(tf.getText())<0))
            {
            l2.setText("ERROR: use key between 0 and 999");
            c5=0;
            }
         else 
         { c5++; }
       }
 if(c5==3){
        int key=Integer.parseInt(tf.getText());
        h=(key+1)%n;
     if(btn[h].getLabel().equals(tf.getText()))
     {          
          l[0].setVisible(false);
          l[h].setVisible(true);
          l2.setText("Have found item with key  "+tf.getText()+"  at index  "+h); 
     }
     else 
     {    
          l[0].setVisible(false);
          l[h].setVisible(true);
          l2.setText("Cannot find item with key  "+tf.getText()+"  at index  "+h); 
     }
 }
 if(c5==4){    
    l2.setText("Press any button"); 
    l[h].setVisible(false);
    l[0].setVisible(true);
    c5=0;
 }
}   
    public void actionPerformed(ActionEvent e) {
        if(e.getSource()==btn1)
        {   新建();  }     
         if(e.getSource()==btn2)
        {   添加();  }
        if(e.getSource()==btn3)
        {   插入();  }
        if(e.getSource()==btn4)
        {   删除();  }
        if(e.getSource()==btn5)
        {   查找();  }       
    }
}我想让每次有数的按钮前景色显示成白色 不是明显好看嘛 直接用setForeground怎么不行啊