for ループを使用して配列を循環するたびに、コンソールに 1 つの要素 (最初の要素) しか生成されない理由がわかりません。私が見ているのは新人の間違いだと確信しているので、ヒントや提案があれば役立ちます。
テキスト フィールドに入力された 2 つの文字列を比較し、それらが配列に存在しない場合は逆に JOPtionPane メッセージを生成するプログラムを楽しみのために作成しています。これは、将来 vBulletin フォーラムで作成する可能性のあるバトル ハック用ですが、そのステップに進む前にアルゴリズムをいじっています。みんなありがとう!
package battleoptionspart1;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.lang.*;
import javax.swing.border.*;
public class BattleOptionsPart1 extends JFrame{
JButton newthread, previewpost;
JRadioButton battle1;
JTextField postcount, oppA, oppB;
JLabel battle2, max;
JPanel panel;
String [] array = {"Bill","Tom","Wendy", "Paula"};
 public BattleOptionsPart1 () {
        panel = new JPanel();
    Toolkit tool = Toolkit.getDefaultToolkit();
    Dimension dim = tool.getScreenSize();
    this.setSize(500, 500);
    this.setTitle("Battle Options");
    GridLayout grid = new GridLayout(0,1,2,2);
    this.setLayout(grid);
    newthread = new JButton("Post New Thread");
    previewpost = new JButton("Preview Post");
    postcount = new JTextField("", 4);
    oppA = new JTextField("",10);
    oppB = new JTextField("",10);
    battle1 = new JRadioButton();
    battle2 = new JLabel("Would you like to start a recorded battle?");
    max = new JLabel("Enter max post count user must have to vote");
    ListenForButton listen = new ListenForButton();
    newthread.addActionListener(listen);
    previewpost.addActionListener(listen);
    JPanel opponents = new JPanel();
    Border oppBorder = BorderFactory.createTitledBorder("Battlers");
    opponents.setBorder(oppBorder);
    opponents.add(oppA);
    opponents.add(oppB);
    JPanel battle = new JPanel();
    Border battleBorder = BorderFactory.createTitledBorder("Start Battle");
    battle.setBorder(battleBorder);
    battle.add(battle1);
    battle.add(battle2);
    JPanel buttons = new JPanel();
    Border buttonBorder = BorderFactory.createTitledBorder("Create Thread");
    buttons.setBorder(buttonBorder);
    buttons.add(newthread);
    buttons.add(previewpost);
    JPanel restriction = new JPanel();
    Border resBorder = BorderFactory.createTitledBorder("Restrictions");
    restriction.setBorder(buttonBorder);
    restriction.add(postcount);
    restriction.add(max);
    this.add(opponents);
    this.add(battle);
    this.add(restriction);
    this.add(buttons);
    this.add(panel);
    int xPos = (dim.width / 2) - (this.getWidth() / 2);
  int yPos = (dim.height / 2) - (this.getHeight() / 2);
  this.setLocation(xPos,yPos); //places form in the middle
  this.setVisible(true); // users can see form
  this.setResizable(false); //users can't resize the form
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
 private class ListenForButton implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e) {
        String compareA = oppA.getText();
        String compareB = oppB.getText();
        if (e.getSource() == newthread)
        {   
            System.out.println(compareA + "\n" + compareB);
            for(int j = 0; j < array.length; j++)
            {
                System.out.println(array[j]);
                if(!compareA.equals(array[j]))
                {
                    JOptionPane.showMessageDialog(null, compareA + " doesn't exist!", "Error Message", JOptionPane.ERROR_MESSAGE);
                    oppA.requestFocus();
                    break;
                }
                if (!compareB.equals(array[j]))
                {
                    JOptionPane.showMessageDialog(null, compareB + " doesn't exist!", "Error Message", JOptionPane.ERROR_MESSAGE);
                    oppB.requestFocus();
                    break;
                }
                else 
                {
                    JOptionPane.showMessageDialog(null, "New thread created successfully!", "Success", JOptionPane.INFORMATION_MESSAGE);
                    break;
                }
            }
        }
        else if (e.getSource() == previewpost)
        {
            System.exit(0);
        }
    }
 }
public static void main(String[] args) {
   BattleOptionsPart1 battle = new BattleOptionsPart1();
}
}