java简单程序

应该可以了,是你定义了MouseHandler定义了一个MouseAdapter的方法而没有用到,把mouserHandler改成mousePressed或者是mouseReleased就可以了下面是代码:

package comboby;

import javaawt;

import javaawtevent;

import javautil;

import javaawtgeom;

import javaxswing;

public class MouseTest {

public static void main(String[] args) {

MouseFrame frame = new MouseFrame();

framesetDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

framesetVisible(true);

}

}

class MouseFrame extends JFrame {

public MouseFrame() {

setTitle("MouseTest");

setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

MousePanel panel = new MousePanel();

Container contentPane = getContentPane();

contentPaneadd(panel);

}

public static final int DEFAULT_WIDTH = 300;

public static final int DEFAULT_HEIGHT = 200;

}

class MousePanel extends JPanel {

public MousePanel() {

squares = new ArrayList();

current = null;

addMouseListener(new MouseHandler());

addMouseMotionListener(new MouseMotionHandler());

}

public void paintComponent(Graphics g) {

superpaintComponent(g);

Graphics2D g2 = (Graphics2D) g;

g2setPaint(ColorRED);

for (int i = 0; i < squaressize(); i++)

g2draw((Rectangle2D) squaresget(i));

}

public Rectangle2D find(Point2D p) {

for (int i = 0; i < squaressize(); i++) {

Rectangle2D r = (Rectangle2D) squaresget(i);

if (rcontains(p))

return r;

}

return null;

}

public void add(Point2D p) {

double x = pgetX();

double y = pgetY();

current = new Rectangle2DDouble(x - SIDELENGTH / 2,

y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);

squaresadd(current);

repaint();

}

public void remove(Rectangle2D s) {

if (s == null)

return;

if (s == current)

current = null;

squaresremove(s);

repaint();

}

private static final int SIDELENGTH = 10;

private ArrayList squares;

private Rectangle2D current;

private class MouseHandler extends MouseAdapter {

public void mouseReleased(MouseEvent event) {

current = find(eventgetPoint());

if (current == null)

add(eventgetPoint());

}

public void mouseClicked(MouseEvent event) {

current = find(eventgetPoint());

if (current == null && eventgetClickCount() >= 2)

remove(current);

}

}

private class MouseMotionHandler implements MouseMotionListener

{

public void mouseMoved(MouseEvent event) {

if (find(eventgetPoint()) == null)

setCursor(CursorgetDefaultCursor());

else

setCursor(CursorgetPredefinedCursor(CursorCROSSHAIR_CURSOR));

}

public void mouseDragged(MouseEvent event) {

if (current != null) {

int x = eventgetX();

int y = eventgetY();

currentsetFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2,

SIDELENGTH, SIDELENGTH);

repaint();

}

}

}

}

//＃＃＃＃＃＃＃＃＃计算器＃＃＃＃＃

import javaawtContainer;

import javaawtFlowLayout;

import javaawtGridLayout;

import javaawteventActionEvent;

import javaawteventActionListener;

import javaawteventMouseMotionListener;

import javatextDecimalFormat;

import javaxswing;

public class 计数器_一般 extends JFrame implements ActionListener {

private JButton an[];

private JButton qingkong;

private JTextField k;

private JPanel rq1, rq2;

private String string[] = { "7", "8", "9", "/", "6", "5", "4", "", "3",

"2", "1", "-", "0", "", "=", "+" };

private String s = "", shu1 = "", shu2 = "", shu3 = "";

private static int fo = 0;

private boolean ff = true;

public 计数器_一般() {

Container c = getContentPane();

csetLayout(new FlowLayout());

// csetLayout(new GridLayout(2,1));

rq1 = new JPanel();

k = new JTextField(10);

qingkong = new JButton("C");

rq1add(k);

rq1add(qingkong);

rq2 = new JPanel();

rq2setLayout(new GridLayout(4, 4, 3, 3));

an = new JButton[stringlength];

for (int i = 0; i < stringlength; i++) {

an[i] = new JButton(string[i]);

an[i]addActionListener(this);

rq2add(an[i]);

}

cadd(rq1);

cadd(rq2);

qingkongaddActionListener(this);

setSize(190, 200);

setVisible(true);

}

public static void main(String[] args) {

计数器_一般 s = new 计数器_一般();

ssetDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

}

public void actionPerformed(ActionEvent e) {

if (!(egetSource() == an[3] || egetSource() == an[7]

|| egetSource() == an[11] || egetSource() == an[13]

|| egetSource() == an[14] || egetSource() == an[15] || e

getSource() == qingkong)) {

if (egetSource() == an[12]) {

s += egetActionCommand();

char a = scharAt(0);

if (a == '0') {

s = "0";

ksetText(s);

}

} else {

s += egetActionCommand();

ksetText(s);

ff = true;

}

} else {

if (egetSource() == qingkong) {

ksetText("");

fo = 0;

shu1 = "";

s = "";

}

if (egetSource() == an[13]) {

String ss = s;

ss += egetActionCommand();

char a = sscharAt(0);

if (a == '') {

s = "";

} else {

if (ssmatches("[0-9]")) {

s += egetActionCommand();

ksetText(s);

}

}

}

if (ff) {

ff = false;

if (egetSource() == an[3]) {

if (kgetText()equals(""))

;

else {

if (shu1equals("")) {

shu1 = kgetText();

ksetText("/");

s = "";

fo = 3;

} else {

shu2 = kgetText();

jishu(fo, shu1, shu2);

fo = 3;

}

}

}

if (egetSource() == an[7]) {

if (kgetText()equals(""))

;

else {

if (shu1equals("")) {

shu1 = kgetText();

ksetText("");

s = "";

fo = 7;

} else {

shu2 = kgetText();

jishu(fo, shu1, shu2);

fo = 7;

}

}

}

if (egetSource() == an[11]) {

if (kgetText()equals(""))

;

else {

if (shu1equals("")) {

shu1 = kgetText();

ksetText("-");

s = "";

fo = 11;

} else {

shu2 = kgetText();

jishu(fo, shu1, shu2);

fo = 11;

}

}

}

if (egetSource() == an[15]) {

if (kgetText()equals(""))

;

else {

if (shu1equals("")) {

shu1 = kgetText();

ksetText("+");

s = "";

fo = 15;

} else {

shu2 = kgetText();

jishu(fo, shu1, shu2);

fo = 15;

}

}

}

if (egetSource() == an[14]) {

if (kgetText()equals("") || shu1equals(""))

;

else {

shu2 = kgetText();

jishu(fo, shu1, shu2);

}

}

}

}

}

public void jishu(int fj, String s1, String s2) {

DecimalFormat twoDigits = new DecimalFormat("000");

double a, b;

a = DoubleparseDouble(s1);

b = DoubleparseDouble(s2);

switch (fj) {

case 3:

shu3 = twoDigitsformat((double) (a / b));

ksetText(shu3);

break;

case 7:

shu3 = twoDigitsformat((double) (a b));

ksetText(shu3);

break;

case 11:

shu3 = twoDigitsformat((double) (a - b));

ksetText(shu3);

break;

case 15:

shu3 = twoDigitsformat((double) (a + b));

ksetText(shu3);

break;

}

s = "";

shu1 = shu3;

shu2 = "";

}

}

//＃＃＃＃＃＃＃＃＃＃＃＃显示当前时间＃＃＃＃＃＃＃＃＃＃＃＃＃＃＃

import javaawtContainer;

import javautilDate;

import javaxswingJFrame;

import javaxswingJLabel;

public class Test extends JFrame implements Runnable {

JLabel jl;

Date now;

public Test() {

Container c = getContentPane();

jl = new JLabel();

cadd(jl);

setSize(280, 80);

setVisible(true);

}

public static void main(String[] args) {

Test s = new Test();

Thread t1=new Thread(s);

t1start();

ssetDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

}

public void run() {

while (true) {

now = new Date();

jlsetText("当前时间是："+now);

try {

Threadsleep(1000); //1秒动一次

} catch (Exception e) {

eprintStackTrace();

}

}

}

}

已测试：

class Stu{

private String name;

private double english;

private double math;

private double chinese;

public Stu(){}

public Stu(String name){

thisname=name;

}

public void setGrades(double english,double math,double chinese){

thisenglish=english;

thismath=math;

thischinese=chinese;

}

public double getTotalGrades(){

return english+math+chinese;

}

public String toString()

{

return thisname + "\t" + thisenglish + "\t" + thismath + "\t" + thischinese+"\t" + thisgetTotalGrades();

}

}

public class Test

{

public static void main(String[] args)

{

double[] grades={

70,80,90,

71,72,73,

72,73,74,

73,74,75,

76,77,78,

61,62,63,

62,63,64,

63,64,65,

64,65,76,

90,90,90

};

Stu[] stu=new Stu[10];

int i=0;

for(i=0;i<10;i++){

stu[i]=new Stu("stu"+i+1);

}

for(i=0;i<30;i+=3)

stu[i/3]setGrades(grades[i],grades[i+1],grades[i+2]);

Test t=new Test();

tsort(stu);

Systemoutprintln("名次\t姓名\t语文\t数学\t英语\t总分");

for(i=0;i<10;i++)

{

Systemoutprint(i+1 + "\t");

Systemoutprintln(stu[i]);

}

}

public void sort(Stu[] stu){

int least=0;

for(int i=0;i<stulength-1;i++){

least=i;

for(int j=i+1;j<stulength;j++){

if(stu[least]getTotalGrades()<stu[j]getTotalGrades())

least=j;

}

if(i!=least) swap(stu,i,least);//交换

}

}

//两个数交换

private void swap(Stu[] stu,int one,int two){

Stu temp=stu[one];

stu[one]=stu[two];

stu[two]=temp;

}

}

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