本文实例讲述了java实现的计算器功能。分享给大家供大家参考，具体如下：
?
|
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.zzvips.com - 计算器");
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("除数不能为零");
} else {
resultNum /= getNumberFromText();
}
} else if (operator.equals("1/x")) {
if (resultNum == 0.0) {
operateValidFlag = false;
resultText.setText("零没有倒数");
} 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);
}
}
|
运行效果：
希望本文所述对大家java程序设计有所帮助。
原文链接：http://blog.csdn.net/wenzhilanyu2012/article/details/8721227
相关文章
猜你喜欢
- 64M VPS建站：能否支持高流量网站运行？ 2025-06-10
- 64M VPS建站：怎样选择合适的域名和SSL证书？ 2025-06-10
- 64M VPS建站：怎样优化以提高网站加载速度？ 2025-06-10
- 64M VPS建站：是否适合初学者操作和管理？ 2025-06-10
- ASP.NET自助建站系统中的用户注册和登录功能定制方法 2025-06-10
