種子論壇 | 高雄市資訊培育協會學員討論區

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Ch82 implements ActionListener
{
private JFrame fm;
private JLabel lb1, lb2;
private JTextField tf1, tf2;
private JButton btn1, btn2;
Ch82()
{
lb1=new JLabel("1坪=3.3058平方公尺",JLabel.CENTER);
lb1.setBounds(0, 10, 215, 30);
lb2=new JLabel("輸入坪數:");
lb2.setBounds(10, 40, 60, 40);
tf1=new JTextField();
tf1.setBounds(70, 45, 134, 30);
tf1.addActionListener(this);
tf2=new JTextField();
tf2.setBounds(10, 85, 195, 40);
tf2.setEditable(false);
btn1=new JButton("確定");
btn1.setBounds(10, 135, 92, 25);
btn1.addActionListener(this);
btn2=new JButton("清除");
btn2.setBounds(112, 135, 92, 25);
btn2.addActionListener(this);
fm=new JFrame("土地面積計算");
fm.setBounds(100, 100, 220, 200);
fm.setVisible(true);
fm.setResizable(false);
fm.setLayout(null);
fm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fm.add(lb1);
fm.add(lb2);
fm.add(tf1);
fm.add(tf2);
fm.add(btn1);
fm.add(btn2);
}
public void actionPerformed(ActionEvent e) //實作 actionPerformed() 方法，參數 e 就是 ActionEvent 物件
{
if(e.getSource()==tf1 || e.getSource()==btn1)
{
double area=Double.parseDouble(tf1.getText())*3.3058;
//String areaStr=String.valueOf(area);
//String areaStr=Double.toString(area);
//tf2.setText("面積為: "+areaStr+" 平方公尺");
tf2.setText("面積為: "+area+" 平方公尺");
}
if(e.getSource()==btn2)
{
tf1.setText("");
tf2.setText("");
}
}
public static void main(String[] args) {
Ch82 app=new Ch82();
}
}

複製代碼