如下代码: public void paint(Graphics g){ Graphics2D g2=(Graphics2D)g; //加上以下两句,将背景重绘 g2.setColor(getContentPane().getBackground()); g2.fillRect(0,0,getContentPane().getWidth(),getContentPane().getHeight()); g2.setColor(Color.blue); g2.fillRect(fg.getx(), fg.gety(), h, w); }
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记得采纳啊
找到了，很久以前写的一个简单画图，呵呵～当时要求用AWT写，很难受。
package net.miqiang.gui;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
/**
* 简单画图板程序
* 好久没用 AWT 了，写起来真别扭，如果用 swing 会很舒服，有空再改写吧。
*
* @author 米强
*
*/
public class TestMain extends Frame {
// 画板
private Palette palette = null;
// 显示当前颜色的面板
private Panel nonceColor = null;
// 画笔粗细
private Label drawWidth = null;
// 画笔端点的装饰
private Label drawCap = null;
// 选取颜色按钮的监听事件类
private ButtonColorAction buttonColorAction = null;
// 鼠标进入按钮后光标样式的监听事件类
private ButtonCursor buttonCursor = null;
// 画笔样式的监听事件
private ButtonStrokeAction buttonStrokeAction = null;
/**
* 构造方法
*
*/
public TestMain() {
// 设置标题栏文字
super("简易画图板");
// 构造一个画图板
palette = new Palette();
Panel pane = new Panel(new GridLayout(2, 1));
// 画笔颜色选择器
Panel paneColor = new Panel(new GridLayout(1, 13));
// 12 个颜色选择按钮
Button [] buttonColor = new Button[12];
Color [] color = {Color.black, Color.blue, Color.cyan, Color.darkGray, Color.gray, Color.green, Color.magenta, Color.orange, Color.pink, Color.red, Color.white, Color.yellow};
// 显示当前颜色的面板
nonceColor = new Panel();
nonceColor.setBackground(Color.black);
paneColor.add(nonceColor);
buttonColorAction = new ButtonColorAction();
buttonCursor = new ButtonCursor();
for(int i = 0; i buttonColor.length; i++){
buttonColor[i] = new Button();
buttonColor[i].setBackground(color[i]);
buttonColor[i].addActionListener(buttonColorAction);
buttonColor[i].addMouseListener(buttonCursor);
paneColor.add(buttonColor[i]);
}
pane.add(paneColor);
// 画笔颜色选择器
Panel paneStroke = new Panel(new GridLayout(1, 13));
// 控制画笔样式
buttonStrokeAction = new ButtonStrokeAction();
Button [] buttonStroke = new Button[11];
buttonStroke[0] = new Button("1");
buttonStroke[1] = new Button("3");
buttonStroke[2] = new Button("5");
buttonStroke[3] = new Button("7");
buttonStroke[4] = new Button("9");
buttonStroke[5] = new Button("11");
buttonStroke[6] = new Button("13");
buttonStroke[7] = new Button("15");
buttonStroke[8] = new Button("17");
buttonStroke[9] = new Button("■");
buttonStroke[10] = new Button("●");
drawWidth = new Label("3", Label.CENTER);
drawCap = new Label("●", Label.CENTER);
drawWidth.setBackground(Color.lightGray);
drawCap.setBackground(Color.lightGray);
paneStroke.add(drawWidth);
for(int i = 0; i buttonStroke.length; i++){
paneStroke.add(buttonStroke[i]);
buttonStroke[i].addMouseListener(buttonCursor);
buttonStroke[i].addActionListener(buttonStrokeAction);
if(i = 8){
buttonStroke[i].setName("width");
}else{
buttonStroke[i].setName("cap");
}
if(i == 8){
paneStroke.add(drawCap);
}
}
pane.add(paneStroke);
// 将画笔颜色选择器添加到窗体中
this.add(pane, BorderLayout.NORTH);
// 将画图板添加到窗体中
this.add(palette);
// 添加窗口监听，点击关闭按钮时退出程序
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
// 设置窗体 ICON 图标
this.setIconImage(Toolkit.getDefaultToolkit().createImage("images/palette.png"));
// 设置窗口的大小
this.setSize(new Dimension(400, 430));
// 设置窗口位置，处于屏幕正中央
this.setLocationRelativeTo(null);
// 显示窗口
this.setVisible(true);
}
/**
* 程序入口
*
* @param args
* 字符串数组参数
*/
public static void main(String[] args) {
new TestMain();
}
/**
* 选取颜色按钮的监听事件类
* @author 米强
*
*/
class ButtonColorAction implements ActionListener {
public void actionPerformed(ActionEvent e) {
Color color_temp = ((Button)e.getSource()).getBackground();
nonceColor.setBackground(color_temp);
palette.setColor(color_temp);
}
}
/**
* 鼠标进入按钮变换光标样式监听事件类
* @author 米强
*
*/
class ButtonCursor extends MouseAdapter {
public void mouseEntered(MouseEvent e) {
((Button)e.getSource()).setCursor(new Cursor(Cursor.HAND_CURSOR));
}
public void mouseExited(MouseEvent e) {
((Button)e.getSource()).setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
}
/**
* 设置画笔的监听事件类
* @author 米强
*
*/
class ButtonStrokeAction implements ActionListener {
public void actionPerformed(ActionEvent e) {
Button button_temp = (Button) e.getSource();
String name = button_temp.getName();
if(name.equalsIgnoreCase("width")){
drawWidth.setText(button_temp.getLabel());
palette.setStroke(Float.parseFloat(button_temp.getLabel()));
}else if(name.equalsIgnoreCase("cap")){
drawCap.setText(button_temp.getLabel());
if(button_temp.getLabel().equals("■")){
palette.setStroke(BasicStroke.CAP_SQUARE);
}else if(button_temp.getLabel().equals("●")){
palette.setStroke(BasicStroke.CAP_ROUND);
}
}
}
}
}
/**
* 画板类
*
* @author 米强
*
*/
class Palette extends Panel implements MouseListener, MouseMotionListener {
// 鼠标 X 坐标的位置
private int mouseX = 0;
// 上一次 X 坐标位置
private int oldMouseX = 0;
// 鼠标 Y 坐标的位置
private int mouseY = 0;
// 上一次 Y 坐标位置
private int oldMouseY = 0;
// 画图颜色
private Color color = null;
// 画笔样式
private BasicStroke stroke = null;
// 缓存图形
private BufferedImage image = null;
/**
* 构造一个画板类
*
*/
public Palette() {
this.addMouseListener(this);
this.addMouseMotionListener(this);
// 默认黑色画笔
color = new Color(0, 0, 0);
// 设置默认画笔样式
stroke = new BasicStroke(3.0f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
// 建立 1280 * 1024 的 RGB 缓存图象
image = new BufferedImage(1280, 1024, BufferedImage.TYPE_INT_RGB);
// 设置颜色
image.getGraphics().setColor(Color.white);
// 画背景
image.getGraphics().fillRect(0, 0, 1280, 1024);
}
/**
* 重写 paint 绘图方法
*/
public void paint(Graphics g) {
super.paint(g);
// 转换为 Graphics2D
Graphics2D g2d = (Graphics2D) g;
// 获取缓存图形 Graphics2D
Graphics2D bg = image.createGraphics();
// 图形抗锯齿
bg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// 设置绘图颜色
bg.setColor(color);
// 设置画笔样式
bg.setStroke(stroke);
// 画线，从上一个点到新的点
bg.drawLine(oldMouseX, oldMouseY, mouseX, mouseY);
// 将缓存中的图形画到画板上
g2d.drawImage(image, 0, 0, this);
}
/**
* 重写 update 方法
*/
public void update(Graphics g) {
this.paint(g);
}
/**
* @return stroke
*/
public BasicStroke getStroke() {
return stroke;
}
/**
* @param stroke 要设置的 stroke
*/
public void setStroke(BasicStroke stroke) {
this.stroke = stroke;
}
/**
* 设置画笔粗细
* @param width
*/
public void setStroke(float width) {
this.stroke = new BasicStroke(width, stroke.getEndCap(), stroke.getLineJoin());
}
/**
* 设置画笔端点的装饰
* @param cap 参考 java.awt.BasicStroke 类静态字段
*/
public void setStroke(int cap) {
this.stroke = new BasicStroke(stroke.getLineWidth(), cap, stroke.getLineJoin());
}
/**
* @return color
*/
public Color getColor() {
return color;
}
/**
* @param color 要设置的 color
*/
public void setColor(Color color) {
this.color = color;
}
public void mouseClicked(MouseEvent mouseEvent) {
}
/**
* 鼠标按下
*/
public void mousePressed(MouseEvent mouseEvent) {
this.oldMouseX = this.mouseX = mouseEvent.getX();
this.oldMouseY = this.mouseY = mouseEvent.getY();
repaint();
}
public void mouseReleased(MouseEvent mouseEvent) {
}
/**
* 鼠标进入棋盘
*/
public void mouseEntered(MouseEvent mouseEvent) {
this.setCursor(new Cursor(Cursor.CROSSHAIR_CURSOR));
}
/**
* 鼠标退出棋盘
*/
public void mouseExited(MouseEvent mouseEvent) {
this.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
/**
* 鼠标拖动
*/
public void mouseDragged(MouseEvent mouseEvent) {
this.oldMouseX = this.mouseX;
this.oldMouseY = this.mouseY;
this.mouseX = mouseEvent.getX();
this.mouseY = mouseEvent.getY();
repaint();
}
public void mouseMoved(MouseEvent mouseEvent) {
}
}
我之前写过一个这样的，可以给你参考
其中背景图是alarmImage
JLayeredPane alarmLayeredPane=new JLayeredPane();
JPanel jPanel=new JPanel(); //新建面板容器
JLabel jLabel=new JLabel(); //新建标签
jPanel.setBounds(0, -5, alarmImage.getIconWidth(), alarmImage.getIconHeight());//设置面板大小
jLabel=new JLabel(alarmImage); //创建具有指定图像的JLabel实例
jPanel.add(jLabel); //将标签加到面板容器中去
alarmLayeredPane.add(jPanel, alarmLayeredPane.DEFAULT_LAYER); //再将面板容器放到层次面板的底层，即背景图
我给你写，已经测试，你看合不合你的意思
package dongzi.pattern;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class SumTest extends JPanel{
JTextField mem[] = new JTextField[10] ;
JButton sumButton = new JButton("SUM") ;
JTextField sumText = new JTextField(4) ;
public SumTest() {
setLayout(new FlowLayout()) ;
for (int i = 0; i 10; i++) {
mem[i] = new JTextField(4) ;
add(mem[i]) ;
}
add(sumButton) ;
add(sumText) ;
sumButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
int sum = 0 ;
for (int i = 0 ;i 10; i++) {
sum += Integer.parseInt(mem[i].getText().trim()) ;
}
sumText.setText(String.valueOf(sum)) ;
}
}) ;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame = new JFrame() ;
SumTest test = new SumTest() ;
frame.add(test) ;
frame.setSize(800, 100) ;
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ;
frame.setVisible(true) ;
}
}
用个HashMap存储信息到文件，可以的话那么代码如下:
import java.util.*
import java.io.*
public class Test1
按照你的要求编写的Java程序如下
public class CC {
public static void main(String[] args) {
int N=5;
for(int i=0;iN;i++){
for(int j=0;jN-i;j++){
System.out.print(" ");
}
for(int j=0;j=i;j++){
System.out.print((char)('a'+i)+" ");
}
System.out.println();
}
}
}
运行结果