Source:
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class CaculatorDemo extends JFrame {
private static final long serialVersionUID = 1L;
the StringBuilder sBuilder the StringBuilder = new new Private ();
Private Double A; // intermediate variable for storing a first number of input
private Double b; // intermediate variables, a second input for storing the number of
private Double double1; // means for receiving the calculation results
private Integer i; // i for indicating Math
public CaculatorDemo() {
this.setTitle("计算器");
this.setSize(318, 457);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
this.getContentPane().add(panel);
panel.setLayout(null);
// define a label for displaying input data and results
Final the JLabel = new new label the JLabel ();
label.setBounds (0, 0, 300, 50);
label.setFont (new new the Font ( "Dialog",. 1, 30) );
label.setOpaque (to true); // default due jlabel transparent, the background color is provided directly not valid, the opaque first set to true
label.setBackground (Color.white);
panel.add (label);
// 定义按钮组件
JButton button1 = new JButton("1");
JButton button2 = new JButton("2");
JButton button3 = new JButton("3");
JButton button4 = new JButton("4");
JButton button5 = new JButton("5");
JButton button6 = new JButton("6");
JButton button7 = new JButton("7");
JButton button8 = new JButton("8");
JButton button9 = new JButton("9");
JButton button0 = new JButton("0");
JButton buttonadd = new JButton("+");// 加
JButton buttonminus = new JButton("-");// 减
JButton buttontime = new JButton("×");// 乘
JButton buttondivid = new JButton("÷");// addition decimalJButton buttondecimal = new JButton ( ".
equalJButton buttonequal = new JButton ( "=
JButton buttondelet = new JButton("←");// 删除
JButton buttonclear = new JButton("C");// 清除
// 定义按钮组件位置
button0.setBounds(0, 50, 100, 60);
button0.setFont(new Font("dialog", 1, 30));
panel.add(button0);
button1.setBounds(100, 50, 100, 60);
button1.setFont(new Font("dialog", 1, 30));
panel.add(button1);
button2.setBounds(200, 50, 100, 60);
button2.setFont(new Font("dialog", 1, 30));
panel.add(button2);
button3.setBounds(0, 110, 100, 60);
button3.setFont(new Font("dialog", 1, 30));
panel.add(button3);
button4.setBounds(100, 110, 100, 60);
button4.setFont(new Font("dialog", 1, 30));
panel.add(button4);
button5.setBounds(200, 110, 100, 60);
button5.setFont(new Font("dialog", 1, 30));
panel.add(button5);
button6.setBounds(0, 170, 100, 60);
button6.setFont(new Font("dialog", 1, 30));
panel.add(button6);
button7.setBounds(100, 170, 100, 60);
button7.setFont(new Font("dialog", 1, 30));
panel.add(button7);
button8.setBounds(200, 170, 100, 60);
button8.setFont(new Font("dialog", 1, 30));
panel.add(button8);
button9.setBounds(0, 230, 100, 60);
button9.setFont(new Font("dialog", 1, 30));
panel.add(button9);
buttonadd.setBounds(100, 230, 100, 60);
buttonadd.setFont(new Font("dialog", 1, 30));
panel.add(buttonadd);//加
buttonminus.setBounds(200, 230, 100, 60);
buttonminus.setFont(new Font("dialog", 1, 30));
panel.add (buttonminus); // Save
buttontime.setBounds(0, 290, 100, 60);
buttontime.setFont(new Font("dialog", 1, 30));
panel.add(buttontime);//乘
buttondivid.setBounds(100, 290, 100, 60);
buttondivid.setFont(new Font("dialog", 1, 30));
panel.add(buttondivid);//除
buttonequal.setBounds(200, 290, 100, 60);
buttonequal.setFont(new Font("dialog", 1, 30));
panel.add(buttonequal);//等于
buttondecimal.setBounds(0, 350, 100, 60);
buttondecimal.setFont(new Font("dialog", 1, 30));
panel.add(buttondecimal);//小数点
buttonclear.setBounds(100, 350, 100, 60);
buttonclear.setFont(new Font("dialog", 1, 30));
panel.add(buttonclear);//复位
buttondelet.setBounds(200, 350, 100, 60);
buttondelet.setFont(new Font("dialog", 1, 30));
panel.add(buttondelet);//删除
// set to the respective operation buttons listener
// numerical input operation. 9 ~ 0
button0.addActionListener (the ActionListener new new () {
public void the actionPerformed (the ActionEvent E) {
sBuilder.append ( "0");
label.setText (sBuilder.toString ());
}
});
button1.addActionListener (the ActionListener new new () {
public void the actionPerformed (the ActionEvent E) {
sBuilder.append ( ". 1");
label.setText (sBuilder.toString ());
}
});
Button2 .addActionListener (new ActionListener () {
@Override
public void actionPerformed(ActionEvent e) {
sBuilder.append("2");
label.setText(sBuilder.toString());
}
});
button3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("3");
label.setText(sBuilder.toString());
}
});
button4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("4");
label.setText(sBuilder.toString());
}
});
button5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("5");
label.setText(sBuilder.toString());
}
});
button6.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("6");
label.setText(sBuilder.toString());
}
});
button7.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("7");
label.setText(sBuilder.toString());
}
});
button8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("8");
label.setText(sBuilder.toString());
}
});
button9.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append("9");
label.setText(sBuilder.toString());
}
});
// 输入运算符操作，需要先判断a是否为0.0
buttonadd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
a = Double.parseDouble(sBuilder.toString());
sBuilder = new StringBuilder();
label.setText("+");
i = 0;
}
});
buttonminus.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
a = Double.parseDouble(sBuilder.toString());
sBuilder = new StringBuilder();
label.setText("-");
i = 1;
}
});
buttontime.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
a = Double.parseDouble(sBuilder.toString());
sBuilder = new StringBuilder();
label.setText("×");
i = 2;
}
});
buttondivid.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
a = Double.parseDouble(sBuilder.toString());
sBuilder = new StringBuilder();
label.setText("÷");
i = 3;
}
});
buttonequal.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// 该判断中间变量是否为空
if (!"".equals(sBuilder.toString()) && (!(a == 0.0))) {
b = Double.parseDouble(sBuilder.toString());
if (i == 0) {
double1 = a + b;
label.setText(double1.toString());
sBuilder = new StringBuilder();
sBuilder.append(double1);
} else if (i == 1) {
double1 = a - b;
label.setText(double1.toString());
sBuilder = new StringBuilder();
sBuilder.append(double1);
} else if (i == 2) {
double1 = a * b;
label.setText(double1.toString());
sBuilder = new StringBuilder();
sBuilder.append(double1);
} else if (i == 3) {
double1 = a / b;
label.setText(double1.toString());
sBuilder = new StringBuilder();
sBuilder.append(double1);
} else {
label.setText(sBuilder.toString());
}
}
}
});
buttondecimal.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder.append(".");
label.setText(sBuilder.toString());
}
});
buttonclear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sBuilder = new StringBuilder();
label.setText("");
}
});
buttondelet.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (!"".equals(sBuilder.toString())) {
sBuilder.deleteCharAt(sBuilder.length() - 1);
label.setText(sBuilder.toString());
}
}
});
this.setVisible(true);
}
public static void main(String[] args) {
new CaculatorDemo();
}
}