import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Total{
	JFrame frame;
	JLabel label1,label2,label3,totalLabel;
	JTextField text1,text2,text3;
	JButton button;
	JPanel panel;
	Total(){
		
		final int SIZE = 3;
		frame = new JFrame("GUI練習(xí)");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		Container c = frame.getContentPane();
		c.setLayout(new BorderLayout(30,30));
		
		Box boxes[] = new Box[4];
		
		boxes[0]=Box.createHorizontalBox();
		boxes[1]=Box.createHorizontalBox();
		boxes[2]=Box.createHorizontalBox();
		boxes[3]=Box.createHorizontalBox();
		
		label1 = new JLabel("Name:");
		label1.setPreferredSize(new Dimension(100,20));
		label1.setMaximumSize(new Dimension(100,20));
		label1.setMinimumSize(new Dimension(100,20));
		label1.setAlignmentX(0);
		
		text1 = new JTextField();
		text1.setPreferredSize(new Dimension(170,40));
		text1.setMaximumSize(new Dimension(170,40));
		text1.setMinimumSize(new Dimension(170,40));
		text1.setAlignmentX(0);
		boxes[0].add(label1);
		boxes[0].add(Box.createHorizontalStrut(25));
		boxes[0].add(text1);
		
		label2 = new JLabel("English:");
		label2.setPreferredSize(new Dimension(100,20));
		label2.setMaximumSize(new Dimension(100,20));
		label2.setMinimumSize(new Dimension(100,20));
		label2.setAlignmentX(0);
		text2 = new JTextField();
		text2.setPreferredSize(new Dimension(170,40));
		text2.setMaximumSize(new Dimension(170,40));
		text2.setMinimumSize(new Dimension(170,40));
		text2.setAlignmentX(0);
		boxes[1].add(label2);
		boxes[1].add(Box.createHorizontalStrut(25));
		boxes[1].add(text2);
		
		label3 = new JLabel("Computer:");
		label3.setPreferredSize(new Dimension(100,20));
		label3.setMaximumSize(new Dimension(100,20));
		label3.setMinimumSize(new Dimension(100,20));
		label3.setAlignmentX(0);
		text3 = new JTextField();
		text3.setPreferredSize(new Dimension(170,40));
		text3.setMaximumSize(new Dimension(170,40));
		text3.setMinimumSize(new Dimension(170,40));
		text3.setAlignmentX(0);
		boxes[2].add(label3);
		boxes[2].add(Box.createHorizontalStrut(25));
		boxes[2].add(text3);
		
		button = new JButton("Total");
		button.setPreferredSize(new Dimension(100,40));
		button.setMaximumSize(new Dimension(100,40));
		button.setMinimumSize(new Dimension(100,40));
		button.setAlignmentX(0);
		
		totalLabel = new JLabel("",JLabel.CENTER);
		totalLabel.setPreferredSize(new Dimension(170,40));
		totalLabel.setMaximumSize(new Dimension(170,40));
		totalLabel.setMinimumSize(new Dimension(170,40));
		totalLabel.setAlignmentX(0);

		

		boxes[3].add(button);
		boxes[3].add(Box.createHorizontalStrut(25));
		boxes[3].add(totalLabel);
		
		panel = new JPanel();
		panel.setLayout(
			new BoxLayout(panel,BoxLayout.Y_AXIS));

		
		panel.add(Box.createVerticalStrut(25));
		panel.add(boxes[0]);
		panel.add(Box.createVerticalStrut(25));
		panel.add(boxes[1]);
		panel.add(Box.createVerticalStrut(25));
		panel.add(boxes[2]);
		panel.add(Box.createVerticalStrut(25));
		panel.add(boxes[3]);

		c.add(panel,BorderLayout.CENTER);
		
		button.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent e){
				try{
					double txt2dbl = Double.parseDouble(text2.getText());
					double txt3dbl = Double.parseDouble(text3.getText());
					totalLabel.setText(""+(txt2dbl+txt3dbl));
				
				}catch (NumberFormatException e1){
					JOptionPane.showMessageDialog(frame,
												"輸入的成績(jī)格式不正確","錯(cuò)誤",
												JOptionPane.PLAIN_MESSAGE);
				}
				
			}
		});
		
		frame.setSize(400,400);
		frame.setVisible(true);
		
		
	}
	
	public static void main(String[] args){
		new Total();
	
	}

}