本文實例講述了java實現的計算器功能。分享給大家供大家參考，具體如下：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
package awtDemo;import java.awt.BorderLayout;import java.awt.Color;import java.awt.GridLayout;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;@SuppressWarnings("serial")public class Calculator extends JFrame implements ActionListener { private final String[] KEYS = { "7", "8", "9", "/", "sqrt", "4", "5", "6", "*", "%", "1", "2", "3", "-", "1/x", "0", "+/-", ".", "+", "=" }; private final String[] COMMAND = { "Backspace", "CE", "C" }; private JButton keys[] = new JButton[KEYS.length]; private JButton commands[] = new JButton[COMMAND.length]; private JTextField resultText = new JTextField("0"); private boolean firstDigit = true; private double resultNum = 0.0; private String operator = "="; private boolean operateValidFlag = true; public Calculator() { init(); this.setBackground(Color.LIGHT_GRAY); this.setTitle("www.ythuaji.com.cn - 計算器"); this.setLocation(500, 300); this.setResizable(false); this.pack(); } private void init() { resultText.setHorizontalAlignment(JTextField.RIGHT); resultText.setEditable(false); resultText.setBackground(Color.white); JPanel calckeysPanel = new JPanel(); calckeysPanel.setLayout(new GridLayout(4, 5, 3, 3)); for (int i = 0; i < KEYS.length; i++) { keys[i] = new JButton(KEYS[i]); calckeysPanel.add(keys[i]); keys[i].setForeground(Color.blue); } keys[3].setForeground(Color.red); keys[8].setForeground(Color.red); keys[13].setForeground(Color.red); keys[18].setForeground(Color.red); keys[19].setForeground(Color.red); JPanel commandsPanel = new JPanel(); commandsPanel.setLayout(new GridLayout(1, 3, 3, 3)); for (int i = 0; i < COMMAND.length; i++) { commands[i] = new JButton(COMMAND[i]); commandsPanel.add(commands[i]); commands[i].setForeground(Color.red); } JPanel panel1 = new JPanel(); panel1.setLayout(new BorderLayout(3, 3)); panel1.add("North", commandsPanel); panel1.add("West", calckeysPanel); JPanel top = new JPanel(); top.setLayout(new BorderLayout()); top.add("Center", resultText); getContentPane().setLayout(new BorderLayout(3, 5)); getContentPane().add("North", top); getContentPane().add("Center", panel1); for (int i = 0; i < KEYS.length; i++) { keys[i].addActionListener(this); } for (int i = 0; i < COMMAND.length; i++) { commands[i].addActionListener(this); } } public void actionPerformed(ActionEvent e) { String label = e.getActionCommand(); if (label.equals(COMMAND[0])) { handleBackspace(); } else if (label.equals(COMMAND[1])) { resultText.setText("0"); } else if (label.equals(COMMAND[2])) { handleC(); } else if ("0123456789.".indexOf(label) >= 0) { handleNumber(label); } else { handleOperator(label); } } private void handleBackspace() { String text = resultText.getText(); int i = text.length(); if (i > 0) { text = text.substring(0, i - 1); if (text.length() == 0) { resultText.setText("0"); firstDigit = true; operator = "="; } else { resultText.setText(text); } } } private void handleNumber(String key) { if (firstDigit) { resultText.setText(key); } else if ((key.equals(".")) && (resultText.getText().indexOf(".") < 0)) { resultText.setText(resultText.getText() + "."); } else if (!key.equals(".")) { resultText.setText(resultText.getText() + key); } firstDigit = false; } private void handleC() { resultText.setText("0"); firstDigit = true; operator = "="; } private void handleOperator(String key) { if (operator.equals("/")) { if (getNumberFromText() == 0.0) { operateValidFlag = false; resultText.setText("除數不能為零"); } else { resultNum /= getNumberFromText(); } } else if (operator.equals("1/x")) { if (resultNum == 0.0) { operateValidFlag = false; resultText.setText("零沒有倒數"); } else { resultNum = 1 / resultNum; } } else if (operator.equals("+")) { resultNum += getNumberFromText(); } else if (operator.equals("-")) { resultNum -= getNumberFromText(); } else if (operator.equals("*")) { resultNum *= getNumberFromText(); } else if (operator.equals("sqrt")) { resultNum = Math.sqrt(resultNum); } else if (operator.equals("%")) { resultNum = resultNum / 100; } else if (operator.equals("+/-")) { resultNum = resultNum * (-1); } else if (operator.equals("=")) { resultNum = getNumberFromText(); } if (operateValidFlag) { long t1; double t2; t1 = (long) resultNum; t2 = resultNum - t1; if (t2 == 0) { resultText.setText(String.valueOf(t1)); } else { resultText.setText(String.valueOf(resultNum)); } } operator = key; firstDigit = true; operateValidFlag = true; } private double getNumberFromText() { double result = 0; try { result = Double.valueOf(resultText.getText()).doubleValue(); } catch (NumberFormatException e) { } return result; } public static void main(String args[]) { Calculator calculator1 = new Calculator(); calculator1.setVisible(true); calculator1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); }} |
運行效果：
希望本文所述對大家java程序設計有所幫助。
原文鏈接：http://blog.csdn.net/wenzhilanyu2012/article/details/8721227
