JAVA GUI TrigonoCalc.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TrigonoCalc extends KeyAdapter implements ActionListener
{
JFrame myframe = new JFrame("計算三角函數");
JRadioButton deg = new JRadioButton("角度");
JRadioButton rad = new JRadioButton("徑度");
JTextField degree = new JTextField();
JTextField sintxt = new JTextField();
JTextField costxt = new JTextField();
JTextField tantxt = new JTextField();
JLabel sinlab = new JLabel(" SIN() ");
JLabel coslab = new JLabel(" COS() ");
JLabel tanlab = new JLabel(" TAN() ");
JButton go = new JButton("計算");
double convert = 180 / Math.PI; //一逕度等於(180/PI) 度

public static void main(String[] args)
{
TrigonoCalc tri = new TrigonoCalc();
tri.init();
}
public void init()
{
Container contentPane = myframe.getContentPane();
JPanel p = new JPanel();
//將兩個元件及JPanel 加入 JFrame
contentPane.add(degree,"North");
contentPane.add(p,"Center");
contentPane.add(go,"South");
  //將JPanel 設定為使用GridLayout(4列，2行)
p.setLayout(new GridLayout(4,2));
//將各元件加到JPanel中
p.add(deg);
p.add(rad);
p.add(sinlab);
p.add(sintxt);
p.add(coslab);
p.add(costxt);
p.add(tanlab);
p.add(tantxt);
//設定選單角度單位的快捷建
deg.setMnemonic(KeyEvent.VK_D);
rad.setMnemonic(KeyEvent.VK_R);

//將兩個單選紐設為一組
ButtonGroup group = new ButtonGroup();
group.add(deg);
group.add(rad);
deg.setSelected(true); //將deg設為預設選取的項目
go.addActionListener(this);
degree.addKeyListener(this);
//單選紐的選取事件之處理方法
deg.addItemListener(
new ItemListener(){
public void itemStateChanged(ItemEvent e){
if(e.getStateChange() == ItemEvent.SELECTED)
convert = 180 / Math.PI;
else
convert = 1;
}
}
);
myframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myframe.setSize(240,240);
myframe.setVisible(true);

}
public void actionPerformed(ActionEvent e)
{
calc();
}
//再輸入區按 ENTER 鍵也進行計算
public void keyPressed(KeyEvent e)
{
if(e.getKeyCode() == KeyEvent.VK_ENTER) calc();
}
public void calc()
{
try
{
//取得輸入區的字串，轉成浮點數後除以角度換算單位
double theta = Double.parseDouble(degree.getText())/convert;
//計算三角函數值，並將結果寫到各文字欄位中
sintxt.setText(Double.toString(Math.sin(theta)));
costxt.setText(Double.toString(Math.cos(theta)));
tantxt.setText(Double.toString(Math.tan(theta)));
}
catch(NumberFormatException e)
{
degree.setText(""); //發生例外時清除輸入區內容
}
}
}