Question

求一个简单的JAVA小程序，要有图形界面。

Answer 1

/*计算器*/
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
public class Calculator implements ActionListener{
JFrame frame;
JPanel panel;
JTextField tfShow;/*定义显示文本框*/
JButton b1[]=new JButton[10]; /*数字按钮*/
JButton b2[]=new JButton[6]; /*操作按钮*/
boolean isNumber;/*判断是否输入多位数字的变量*/
double number;/*存储输入数值、显示结果的变量*/
double result;/*存储中间运算结果的变量*/
char operator;/*存储当前操作符的成员变量*/
public Calculator(){
frame=new JFrame("计算器");
frame.setSize(300,300);/*指定框架窗口的大小*/
frame.setResizable(false);/*使框架窗口不可改变大小*/
JPanel contentPane=(JPanel)frame.getContentPane();
contentPane.setBorder(new EmptyBorder(20,20,20,20));/*绘制框架的指定大小的空透明边框*/
tfShow=new JTextField("0",25);/*指定属性的文本域*/
tfShow.setHorizontalAlignment(JTextField.RIGHT);/*设置文本域中文本的对齐方式*/
isNumber=true;/*初始值设置*/
number=0;/*初始值设置*/
result=0;/*初始值设置*/
operator=' ';/*初始值设置*/
for(int i=0;i<b1.length;i++){
b1[i]=new JButton(Integer.toString(i));/*创建数字按钮*/
b1[i].setActionCommand(Integer.toString(i));
b1[i].addActionListener(this);
b1[i].setForeground(Color.blue);
}
String bs[]={"/","*","-","C","+","="};
for(int i=0;i<b2.length;i++){
b2[i]=new JButton(bs[i]);/*创建操作按钮*/
b2[i].setActionCommand(bs[i]);
b2[i].addActionListener(this);
b2[i].setForeground(Color.red);
}
panel=new JPanel();
panel.setLayout(new GridLayout(4,5));
panel.add(b1[1]);
panel.add(b1[2]);
panel.add(b1[3]);
panel.add(b2[0]);
panel.add(b1[4]);
panel.add(b1[5]);
panel.add(b1[6]);
panel.add(b2[1]);
panel.add(b1[7]);
panel.add(b1[8]);
panel.add(b1[9]);
panel.add(b2[2]);
panel.add(b1[0]);
panel.add(b2[3]);
panel.add(b2[4]);
panel.add(b2[5]);
frame.add(tfShow,BorderLayout.NORTH);/*将文本框放置在框架上方*/
frame.add(panel,BorderLayout.CENTER);/*将装有按钮组的panel放在框架的中心*/
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);/*设置框架窗口的默认窗口关闭操作*/
frame.setVisible(true);/*设置框架可见*/
}
public double getDisplay(){/*返回要显示的结果*/
return number;
}
public void reDisplay(){/*刷新文本域的内容*/
tfShow.setText(""+getDisplay());
}
/*对输入数字的处理*/
public void numberProcess(int num){
if(isNumber&&num!=0){
String s1=Integer.toString(num);
String s2=Integer.toString((int)(this.number));
this.number=Double.parseDouble(s2+s1);/*对多位数字的处理*/
}else{
this.number=num;
}
isNumber=true;/*输入连续数字（即多位数字）时为真*/
}
public void operationProcess(char operator){/*根据输入的操作符改变当前操作符*/
switch(operator){
case '-':
this.operator='-';
break;
case '+':
this.operator='+';
break;
case '*':
this.operator='*';
break;
case '/':
this.operator='/';
break;
}
result=number;
isNumber=false;/*输入操作符时表示输入连续数字的标记变量为假*/
}
public void clear(){
number=0;
result=0;
}
public void equal(){/*计算运算结果*/
switch(operator){
case '-':
result=result-number;
break;
case '+':
result=result+number;
break;
case '*':
result=result*number;
break;
case '/':
result=result/number;
break;
case ' ':
result=number;
break;
}
number=result; /*把运算结果赋值给显示变量*/
isNumber=false;
operator=' ';
}
public static void main(String args[]){
Calculator cal=new Calculator();/*创建计算器*/
}
public void actionPerformed(ActionEvent e){
String command=e.getActionCommand();/*获取按钮激发的操作事件的命令名称*/
char c=command.charAt(0);/*将按钮命令名称的第一个字符赋值给一个字符c*/
switch(c){
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '0':
int number=Integer.parseInt(command);
numberProcess(number);/*输入数字的处理*/
break;
case '+':
case '-':
case '*':
case '/':
operationProcess(c);/*算数运算符的处理*/
break;
case '=':equal();break;/*计算运算结果*/
case 'C':clear();break;/*清零*/
}
reDisplay(); /*在文本域中显示信息*/
}
}
这是我做的一个计算器：运行截图

Answer 2

显示时间的。import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;

public class DateTime extends JApplet {
private static final long serialVersionUID = 1L;
public static final String WEEK_SUN = "SUN";
public static final String WEEK_MON = "MON";
public static final String WEEK_TUE = "TUE";
public static final String WEEK_WED = "WED";
public static final String WEEK_THU = "THU";
public static final String WEEK_FRI = "FRI";
public static final String WEEK_SAT = "SAT";

public static final Color background = Color.white;
public static final Color foreground = Color.black;
public static final Color headerBackground = Color.blue;
public static final Color headerForeground = Color.white;
public static final Color selectedBackground = Color.blue;
public static final Color selectedForeground = Color.white;

private JPanel cPane;
private JLabel yearsLabel;
private JSpinner yearsSpinner;
private JLabel monthsLabel;
private JComboBox monthsComboBox;
private JTable daysTable;
private AbstractTableModel daysModel;
private Calendar calendar;

public DateTime() {
cPane = (JPanel) getContentPane();
}

public void init() {
cPane.setLayout(new BorderLayout());

calendar = Calendar.getInstance();
calendar = Calendar.getInstance();
yearsLabel = new JLabel("Year: ");
yearsSpinner = new JSpinner();
yearsSpinner.setEditor(new JSpinner.NumberEditor(yearsSpinner, "0000"));
yearsSpinner.setValue(new Integer(calendar.get(Calendar.YEAR)));
yearsSpinner.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent changeEvent) {
int day = calendar.get(Calendar.DAY_OF_MONTH);
calendar.set(Calendar.DAY_OF_MONTH, 1);
calendar.set(Calendar.YEAR, ((Integer) yearsSpinner.getValue()).intValue());
int maxDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
calendar.set(Calendar.DAY_OF_MONTH, day > maxDay ? maxDay : day);
updateView();
}
});

JPanel yearMonthPanel = new JPanel();
cPane.add(yearMonthPanel, BorderLayout.NORTH);
yearMonthPanel.setLayout(new BorderLayout());
yearMonthPanel.add(new JPanel(), BorderLayout.CENTER);
JPanel yearPanel = new JPanel();
yearMonthPanel.add(yearPanel, BorderLayout.WEST);
yearPanel.setLayout(new BorderLayout());
yearPanel.add(yearsLabel, BorderLayout.WEST);
yearPanel.add(yearsSpinner, BorderLayout.CENTER);

monthsLabel = new JLabel("Month: ");
monthsComboBox = new JComboBox();
for (int i = 1; i <= 12; i++) {
monthsComboBox.addItem(new Integer(i));
}
monthsComboBox.setSelectedIndex(calendar.get(Calendar.MONTH));
monthsComboBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
int day = calendar.get(Calendar.DAY_OF_MONTH);
calendar.set(Calendar.DAY_OF_MONTH, 1);
calendar.set(Calendar.MONTH, monthsComboBox.getSelectedIndex());
int maxDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
calendar.set(Calendar.DAY_OF_MONTH, day > maxDay ? maxDay : day);
updateView();
}
});
JPanel monthPanel = new JPanel();
yearMonthPanel.add(monthPanel, BorderLayout.EAST);
monthPanel.setLayout(new BorderLayout());
monthPanel.add(monthsLabel, BorderLayout.WEST);
monthPanel.add(monthsComboBox, BorderLayout.CENTER);

daysModel = new AbstractTableModel() {
/**
*
*/
private static final long serialVersionUID = -3517455337953024330L; public int getRowCount() {
return 7;
}

public int getColumnCount() {
return 7;
}

public Object getValueAt(int row, int column) {
if (row == 0) {
return getHeader(column);
}
row--;
Calendar calendar = (Calendar) DateTime.this.calendar.clone();
calendar.set(Calendar.DAY_OF_MONTH, 1);
int dayCount = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
int moreDayCount = calendar.get(Calendar.DAY_OF_WEEK) - 1;
int index = row * 7 + column;
int dayIndex = index - moreDayCount + 1;
if (index < moreDayCount || dayIndex > dayCount) {
return null;
} else {
return new Integer(dayIndex);
}
}
};

daysTable = new CalendarTable(daysModel, calendar);
daysTable.setCellSelectionEnabled(true);
daysTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

daysTable.setDefaultRenderer(daysTable.getColumnClass(0), new TableCellRenderer() {
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
boolean hasFocus, int row, int column) {
String text = (value == null) ? "" : value.toString();
JLabel cell = new JLabel(text);
cell.setOpaque(true);
if (row == 0) {
cell.setForeground(headerForeground);
cell.setBackground(headerBackground);
} else {
if (isSelected) {
cell.setForeground(selectedForeground);
cell.setBackground(selectedBackground);
} else {
cell.setForeground(foreground);
cell.setBackground(background);
}
}

return cell;
}
});
updateView();

cPane.add(daysTable, BorderLayout.CENTER);
}

public static String getHeader(int index) {
switch (index) {
case 0:
return WEEK_SUN;
case 1:
return WEEK_MON;
case 2:
return WEEK_TUE;
case 3:
return WEEK_WED;
case 4:
return WEEK_THU;
case 5:
return WEEK_FRI;
case 6:
return WEEK_SAT;
default:
return null;
}
}

public void updateView() {
daysModel.fireTableDataChanged();
daysTable.setRowSelectionInterval(calendar.get(Calendar.WEEK_OF_MONTH),
calendar.get(Calendar.WEEK_OF_MONTH));
daysTable.setColumnSelectionInterval(calendar.get(Calendar.DAY_OF_WEEK) - 1,
calendar.get(Calendar.DAY_OF_WEEK) - 1);
} public static class CalendarTable extends JTable { /**
*
*/
private static final long serialVersionUID = 1L;
private Calendar calendar; public CalendarTable(TableModel model, Calendar calendar) {
super(model);
this.calendar = calendar;
} public void changeSelection(int row, int column, boolean toggle, boolean extend) {
super.changeSelection(row, column, toggle, extend);
if (row == 0) {
return;
}
Object obj = getValueAt(row, column);
if (obj != null) {
calendar.set(Calendar.DAY_OF_MONTH, ((Integer)obj).intValue());
}
} }

public static void main(String[] args) {
JFrame frame = new JFrame("Calendar Application");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DateTime myCalendar = new DateTime();
myCalendar.init();
frame.getContentPane().add(myCalendar);
frame.setSize(240, 172);
frame.show();
}
}

Answer 3

我有一个通讯录你要吗。。Swing做的