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

public class Lab7_5 extends JApplet implements ActionListener
{
    JLabel idLabel,nameLabel,scoreLabel;
    JTextField idField,nameField,scoreField,statusField;
    JButton addBtn,minBtn,maxBtn,avgBtn;
    JTextArea showData;
        
    String [] id,name= new String[20];
    double score[]=new double[20];
    int i=0 ;
    String str="",str2="",str3="";
    public void init()
    {
        Container container = getContentPane();
        container.setLayout(new FlowLayout());

        idLabel = new JLabel("      Enter Student ID :    ");
        container.add(idLabel);
        idField = new JTextField(15);
        container.add(idField);

        nameLabel = new JLabel("Enter Student Name :");
        container.add(nameLabel);
        nameField = new JTextField(15);
        container.add(nameField);

        scoreLabel = new JLabel("Enter Student Score :");
        container.add(scoreLabel);

        scoreField =  new JTextField(15);
        container.add(scoreField);

        addBtn = new JButton("Add");
        addBtn.addActionListener(this);
        container.add(addBtn);

        String blank="";
        for(int n=1 ; n<=80;n++);
        blank+= "  ";
        container.add(new JLabel(blank));

        showData = new JTextArea(10,26);
        container.add(showData);
        container.add(new JLabel(blank));

        minBtn = new JButton("Minimum");
        minBtn.addActionListener(this);
        container.add(minBtn);

        maxBtn = new JButton("Maximum");
        maxBtn.addActionListener(this);
        container.add(maxBtn);

        avgBtn = new JButton("Average");
        avgBtn.addActionListener(this);
        container.add(avgBtn);

        statusField = new JTextField(26);
        container.add(statusField);
    }
    public void actionPerformed(ActionEvent event)
    {
        if(event.getSource()==addBtn)
            addData();
        else if(event.getSource()==minBtn)
             minData();

    }
    public void addData()
    {
        str=idField.getText();
        str2=nameField.getText();
        str3=scoreField.getText();
    
        showData.append(str+"\t"+str2+"\t"+str3);
        showData.append("\n");
        id=str;
        name=str2;
        score=Double.parseDouble(str3);
        i++;
    }
    public void minData()
    {
    double    min = score[0];
        for(int b=0 ; b<id.length;b++)
        {
            if(min>score)
            min=score ;
        }
        statusField.setText(Double.toString(min));
    }
}


ปัญหาคือมันใช้ array เก็บค่า แล้วพอผมใช้ array ผมแสดง setText ไม่ได้ ถ้ามี[] อยู่เหนือ setText แสดงไม่ออกเลย ทำไงดีครับ