java 小程序 计算器

//以下是实现计算器的代码
import java.applet.Applet;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class cccc extends Applet { /** * */ private static final long serialVersionUID = 1L; //没啥作用 private JButton[] button=new JButton[19]; //定义一个按钮数组 private static final int HEIGHT=50; //确定每个按钮的高度 private static final int LENGTH=50; //确定每个按钮的长度 private static final int INPUT_NUMBER_ONE=0; //定义输入状态 private static final int INPUT_NUMBER_TWO=1; private static final int NOT_INPUT=-1; private int button_X=20; //定按钮的起始坐标 private int button_Y=10; private int i; private int Input_State=INPUT_NUMBER_ONE; //初始化输入状态 private int Operator_num; //操作符的下标 private JTextArea textarea; private String[] s={"7","8","9","/","4","5","6","*","1","2","3","-","0",".","=","+","Clear","Reset","Close"}; //定义一个字符串数组 private StringBuffer s1=new StringBuffer(); private StringBuffer s2=new StringBuffer(); private StringBuffer s4=new StringBuffer(); private String s3=new String(); private String s5=new String(); private double result1; //获取 number_one private double result2; //获取 number_two private double result; //得到最终运算结果 private int []Operator={0,0,0,3,0,0,0,7,0,0,0,11,0,0,14,15}; //对应于按钮数组,不为0的为操作符 public void init() { resize(280,450); //设定页面大小 setLayout(null); //设定布局方式 for (i=0;i<16;i++) { if(i%4==0&&i!=0) //每行设定四个按钮,再次初始化坐标 { button_X=20; button_Y+=60; } button[i]=new JButton(s[i]); //实类化一个按钮 button[i].setBounds(button_X, button_Y, HEIGHT, LENGTH); //确定按钮的坐标与大小 button_X+=60; add(button[i]); button[i].addActionListener(new ButtonAction()); //监听按钮时间 } button_X=20;button_Y=260; textarea=new JTextArea("",5,100); //设定文本域 textarea.setBounds(button_X, button_Y, LENGTH+170, HEIGHT+40); textarea.setBackground(Color.LIGHT_GRAY); textarea.setWrapStyleWord(true); textarea.setEditable(false); add(textarea); button_X=20;button_Y=380; for(i=16;i<19;i++) //设定选择按钮(clear Reset close ) { button[i]=new JButton(s[i]); button[i].setBackground(Color.green); button[i].setBounds(button_X, button_Y, LENGTH+30, HEIGHT-10); button_X+=80; add(button[i]); button[i].addActionListener(new ButtonAction()); } for(i=0;i<5;i++) //只是文本域中布局 { s1=s1.append(" "); } Init_TextArea(); //初始化文本域 } public void Init_TextArea() { textarea.setText(s1+"0\n\n\n\n"+s1+"0"); textarea.setFont(new Font("宋体",100,15)); //设置字体 } //实现监听事件的类 class ButtonAction implements ActionListener { public void actionPerformed(ActionEvent e) { Object obj=e.getSource(); //获取事件源 for(i=0;i<19;i++) //匹配19个按钮 { if(obj==button[i]&&i>15) //3个选择按钮的监听事件 { if(i==17) { s2.delete(0, s2.length()); s4.delete(0, s4.length()); s3=null; s5=null; Input_State=INPUT_NUMBER_ONE; Init_TextArea(); } if(i==18) { System.exit(1); } if(i==16) { if(Input_State==INPUT_NUMBER_ONE) { if(s2.length()==0) { continue; } //字符串删去最后一个字符,用StringBuffer类型会在源字符串上进行操作,减少内存的浪费 s2.deleteCharAt(s2.length()-1); s3=s2.toString(); textarea.setText(s1+" "+s3+"\n\n\n\n"+s1+"0"); //文字输入方式是由左向右 textarea.setAlignmentX(LEFT_ALIGNMENT); } if(Input_State==INPUT_NUMBER_TWO) { if(s4.length()==0) { continue; } s4.deleteCharAt(s4.length()-1); s5=s4.toString(); textarea.setText(s1+s3+"\n\n"+s[Operator[Operator_num]]+s1+s5+"\n\n"+s1+"0"); } } } else { if(obj==button[i]&&Operator[i]!=0) { if(i==14) //如果事件源的按钮是=号 { result1=Double.parseDouble(s3); result2=Double.parseDouble(s5); switch(Operator_num) //选择是哪种操作符 { case 3:result=result1/result2;break; case 7:result=result1*result2;break; case 11:result=result1-result2;break; case 15:result=result1+result2;break; } textarea.setText(s1+s3+"\n\n"+s[Operator[Operator_num]]+s1+s5+"\n\n"+s1+""+result); Input_State=NOT_INPUT; //打印输出结果后,将输入状态设为 NOT_INPUT } else { textarea.setText(s1+s3+"\n\n"+s[Operator[i]]+"\n\n"+s1+"0"); Input_State=INPUT_NUMBER_TWO; s4.delete(0, s4.length()); Operator_num=i; //记录操作符号的下标 } } if(obj==button[i]&&Operator[i]==0) { if(Input_State==INPUT_NUMBER_ONE) { s2.append(s[i]); s3=s2.toString(); textarea.setText(s1+" "+s3+"\n\n\n\n"+s1+"0"); textarea.setAlignmentX(LEFT_ALIGNMENT); } if(Input_State==INPUT_NUMBER_TWO) { s4.append(s[i]); s5=s4.toString(); textarea.setText(s1+s3+"\n\n"+s[Operator[Operator_num]]+s1+s5+"\n\n"+s1+"0"); } } } } } }}
后记: 最近在学西java,突然想实现这样一个程序,所以花费了些事件.上面就是劳动成果.上面只是实现了简单的 运算,但是起始道理都是一样的,如果大家感兴趣的话可以把它修改的更加完善.如果大家有什么好的建议, 请留言.还有如果你把代码拷过去之后有什么错误的话,估计是括号没对齐(就是括号跑到注释里面去了) 因为这里面的编辑器没有自动对齐功能,我也是一个一个修改的.有什么错误大家谅解!.....