java版計算器

fp34 9年前發布 | 2K 次閱讀 Java
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.;
import java.awt.;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.awt.Color;
/**

java版計算器
*/
public class Calculator extends JFrame {
 final int WIN_W = 250, WIN_H = 250;
 JPanel myPanel, panelSuper;
public Calculator() {

 // 主面板
 panelSuper = new JPanel();
 panelSuper.setLayout(null);

 // 設置窗口位置
 double width = Toolkit.getDefaultToolkit().getScreenSize().width;
 double height = Toolkit.getDefaultToolkit().getScreenSize().height;
 this.setBounds((int) (width - WIN_W) / 2, (int) (height - WIN_H) / 2,
         WIN_W, WIN_H);

 // 窗口配置
 this.setTitle("java版計算器");
 this.validate();
 this.setResizable(false);
 this.setVisible(true);
 this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);

 // 添加計算器按鈕面板
 myPanel = new MyPanel();
 this.add(myPanel, BorderLayout.CENTER);


}
public static void main(String[] args) {

 new Calculator();

}
/**

計算器按鈕面板類
*/
class MyPanel extends JPanel implements ActionListener {
 JButton button1, button2, button3, button4, button5, button6, button7,

     button8, button9, button0, buttonJia, buttonJian, buttonCheng,
     buttonChu, buttonDeng, buttonDian, buttonC, buttonDel,
     buttonZF, buttonGH;

JTextField jTextField; // 計算器顯示屏
 char oper; // 操作符
 String key, allKey = "1234567890.±del", jjccKey = "+-*/";
 BigDecimal d1, d2;
 boolean first;
public MyPanel() {

 // 設置布局
 this.setLayout(new FlowLayout(FlowLayout.LEFT, 4, 5));

 // 計算器顯示屏
 jTextField = new JTextField(21);
 jTextField.setHorizontalAlignment(JTextField.RIGHT);
 jTextField.setEditable(false);
 jTextField.setBackground(new Color(255, 255, 255));
 jTextField.setText("0");
 this.add(jTextField);

 // 計算器按鈕
 button1 = new JButton("1");
 button2 = new JButton("2");
 button3 = new JButton("3");
 button4 = new JButton("4");
 button5 = new JButton("5");
 button6 = new JButton("6");
 button7 = new JButton("7");
 button8 = new JButton("8");
 button9 = new JButton("9");
 button0 = new JButton("0");
 buttonJia = new JButton("+");
 buttonJian = new JButton("-");
 buttonCheng = new JButton("*");
 buttonChu = new JButton("/");
 buttonDeng = new JButton("=");
 buttonDian = new JButton(".");
 buttonDel = new JButton("del");
 buttonC = new JButton("c");
 buttonZF = new JButton("±");
 buttonGH = new JButton("√");
 button1.setPreferredSize(new Dimension(55, 30));
 button2.setPreferredSize(new Dimension(55, 30));
 button3.setPreferredSize(new Dimension(55, 30));
 button4.setPreferredSize(new Dimension(55, 30));
 button5.setPreferredSize(new Dimension(55, 30));
 button6.setPreferredSize(new Dimension(55, 30));
 button7.setPreferredSize(new Dimension(55, 30));
 button8.setPreferredSize(new Dimension(55, 30));
 button9.setPreferredSize(new Dimension(55, 30));
 button0.setPreferredSize(new Dimension(55, 30));
 buttonJia.setPreferredSize(new Dimension(55, 30));
 buttonJian.setPreferredSize(new Dimension(55, 30));
 buttonCheng.setPreferredSize(new Dimension(55, 30));
 buttonChu.setPreferredSize(new Dimension(55, 30));
 buttonDeng.setPreferredSize(new Dimension(55, 30));
 buttonDian.setPreferredSize(new Dimension(55, 30));
 buttonDel.setPreferredSize(new Dimension(55, 30));
 buttonC.setPreferredSize(new Dimension(55, 30));
 buttonZF.setPreferredSize(new Dimension(55, 30));
 buttonGH.setPreferredSize(new Dimension(55, 30));
 this.add(buttonDel);
 this.add(buttonC);
 this.add(buttonZF);
 this.add(buttonGH);
 this.add(button1);
 this.add(button2);
 this.add(button3);
 this.add(buttonJia);
 this.add(button4);
 this.add(button5);
 this.add(button6);
 this.add(buttonJian);
 this.add(button7);
 this.add(button8);
 this.add(button9);
 this.add(buttonCheng);
 this.add(button0);
 this.add(buttonDian);
 this.add(buttonDeng);
 this.add(buttonChu);
 buttonDel.addActionListener(this);
 buttonC.addActionListener(this);
 buttonZF.addActionListener(this);
 buttonGH.addActionListener(this);
 button1.addActionListener(this);
 button2.addActionListener(this);
 button3.addActionListener(this);
 button4.addActionListener(this);
 button5.addActionListener(this);
 button6.addActionListener(this);
 button7.addActionListener(this);
 button8.addActionListener(this);
 button9.addActionListener(this);
 button0.addActionListener(this);
 buttonJia.addActionListener(this);
 buttonJian.addActionListener(this);
 buttonCheng.addActionListener(this);
 buttonChu.addActionListener(this);
 buttonDeng.addActionListener(this);
 buttonDian.addActionListener(this);

 // 計算器初始化
 init();

}
/**

計算器初始化
/
public void init() {
 d1 = new BigDecimal("0");
 d1 = new BigDecimal("0");
 key = "=";
 oper = '=';
 jTextField.setText("0");
 first = true; // 用于標記是否進行連續操作（例如按鍵順序為“99====”，第一次等于first由true變為false，如果!first，按等號相當于用上一次的結果與第二個操作數相乘）
}
/**

按鈕監聽
*/
public void actionPerformed(ActionEvent e) {
 JButton b = (JButton) e.getSource();
 if (b == buttonDian) { // 按下.

 jTextField.setText(jTextField.getText() + ".");
 if (first) {
     d2 = d1 = getNum();
 } else {
     d2 = getNum();
 }

} else if (b == buttonZF) {// 按下±

 BigDecimal d = getNum();
 d = new BigDecimal("0").subtract(d);
 setFormatNum(d);
 if (first) {
     d2 = d1 = getNum();
 } else {
     d2 = getNum();
 }

} else if (b == buttonDel) {// 按下del

 if (jTextField.getText().length() == 1
         || jTextField.getText().length() == 2
         && jTextField.getText().startsWith("-")) {
     jTextField.setText("0");

 } else {
     String s = jTextField.getText();
     s = s.substring(0, s.length() - 1);
     if (s.endsWith("E+") || s.endsWith("E-"))
         s = s.substring(0, s.length() - 2);
     jTextField.setText(s);
     if (first) {
         d2 = d1 = getNum();
     } else {
         d2 = getNum();
     }
 }

} else if (b == buttonC) {// 按下c

 init();

} else if (b == buttonJia) {// 按下+

 BigDecimal s;
 if (!first && allKey.indexOf(key) >= 0) {
     if (oper == '-' || oper == '/') {
         s = operate(d1, oper, d2);
     } else {
         s = operate(d2, oper, d1);
     }
     setFormatNum(s);
 }// 如果不是第一次，且上一次操作是對數字進行操作
 else {

     first = false;
 }
 d2 = d1 = getNum();
 // System.out.print("111我執行啦\n");
 oper = '+';

} else if (b == buttonJian) {// 按下-

 BigDecimal s;
 if (!first && allKey.indexOf(key) >= 0) {
     s = operate(d1, oper, d2);
     setFormatNum(s);
 }// 如果不是第一次，且上一次操作是對數字進行操作
 else {
     first = false;
 }
 d2 = d1 = getNum();
 oper = '-';

} else if (b == buttonCheng) {// 按下*

 BigDecimal s;
 if (!first && allKey.indexOf(key) >= 0) {
     if (oper == '-' || oper == '/') {
         s = operate(d1, oper, d2);
     } else {
         s = operate(d2, oper, d1);
     }
     setFormatNum(s);
 }// 如果不是第一次，且上一次操作是對數字進行操作
 else {
     first = false;
 }
 d2 = d1 = getNum();
 oper = '*';

} else if (b == buttonChu) {// 按下/

 BigDecimal s;
 if (!first && allKey.indexOf(key) >= 0) {
     s = operate(d1, oper, d2);
     setFormatNum(s);
 }// 如果不是第一次，且上一次操作是對數字進行操作
 else {
     first = false;
 }
 d2 = d1 = getNum();
 oper = '/';

} else if (b == buttonGH) {// 按下平方根

 if (jTextField.getText().startsWith("-")) {
     init();
     return;
 }
 BigDecimal d = getNum();
 MathContext mc = new MathContext(10, RoundingMode.HALF_DOWN);
 d = new BigDecimal(Math.sqrt(d.doubleValue()), mc);
 setFormatNum(d);
 if (first) {
     d2 = d1 = getNum();
 } else {
     d2 = getNum();
 }

} else if (b == buttonDeng) {// 按下=

 BigDecimal s = null;
 d2 = getNum();
 if (!key.equals("=")) {
     s = operate(d1, oper, d2);
 } else {
     s = operate(d2, oper, d1);
 }
 if (oper != '=' && !key.equals("=")) {// 上一次操作為 +-*/
     d1 = getNum();

 }
 setFormatNum(s);
 first = true;

} else { // 按下其他按鈕

 if (this.jTextField.getText().equals("0")
         || allKey.indexOf(key) == -1) {
     this.jTextField.setText(b.getText());
 } else {
     this.jTextField.setText(jTextField.getText() + b.getText());
 }
 if (first) {
     d2 = d1 = getNum();
 } else {
     d2 = getNum();
 }// d2作被加數:d2+d1

}
 key = b.getText();
}
/**

獲取操作數

@return 操作數
*/
public BigDecimal getNum() {
 BigDecimal d = new BigDecimal(jTextField.getText());
 return d;
}
public void setFormatNum(BigDecimal dd) {
 MathContext mc = new MathContext(18, RoundingMode.HALF_DOWN);
BigDecimal d = new BigDecimal(dd.toString(), mc);
 String num = d.toString();
 if (num.endsWith(".0"))

 num = num.replaceAll("\\.0", "");

this.jTextField.setText(num);
}
/**

計算

@param a1
操作數1
@param c
操作符
@param a2
操作數2
@return
*/
public BigDecimal operate(BigDecimal a1, char c, BigDecimal a2) {
 MathContext mc = new MathContext(10, RoundingMode.HALF_DOWN);
 switch (c) {
 case '+':
 return a1.add(a2);

 case '-':
 return a1.subtract(a2);

 case '*':
 return a1.multiply(a2);

 case '/':
 if (a2.compareTo(new BigDecimal("0")) == 0) {
     init();
     return new BigDecimal("0");
 }
 return a1.divide(a2, mc);

 default:
 return a2;

 }
}
}





}
</pre>
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