类不是抽象的，并且不覆盖抽象方法Java错误TIcTacToe游戏

Question

For a project I have to make a tictactoe game. However I'm having a problem with using ActionListener. It brings up the error that class is not abstract and does not override abstract method.

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

public class GameGUI extends JFrame implements ActionListener{
    private JFrame gFrame = new JFrame("TicTacToe");
    private JButton [][] buttons = new JButton[3][3];
    private JButton reset = new JButton("New Game");


public GameGUI() {
    super("TicTacToe");
    gFrame.setSize(500,380);
    gFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    gFrame.setVisible(true);
    gFrame.setResizable(false);
    gameBoard();
}

// Set everything into the actual game board
private void gameBoard() {
  JPanel mPanel = new JPanel(new BorderLayout());
  JPanel options = new JPanel(new BorderLayout());
  JPanel game = new JPanel(new GridLayout(3,3));               

  gFrame.add(mPanel);                                       

  mPanel.setPreferredSize(new Dimension(325,425));
  options.setPreferredSize(new Dimension(300,50));                    
  game.setPreferredSize(new Dimension(300,300));

  mPanel.add(options, BorderLayout.NORTH);                          
  mPanel.add(game, BorderLayout.CENTER);

  options.add(reset, BorderLayout.NORTH);


for(int i = 0; i < 3; i++){
  for(int j = 0; j < 3; j++){

     buttons[i][j] = new JButton();                
     buttons[i][j].setText("");
     buttons[i][j].setVisible(true);
     buttons[i][j].addActionListener(this);

     game.add(buttons[i][j]);  
    }
 }

I'm not sure how to go about and fix this so any help would be greatly appreciated, I'm fairly new to Java so please excuse if the code is not great.

Answer 1

In this line of code,

buttons[i][j].addActionListener(this);

you're saying that a GameGui object should respond when one of the buttons is clicked. But you haven't specified how it will respond. In other words, you need to write a method that contains the code that you want to run when a button is clicked.

The first line of that method should be

public void actionPerformed(ActionEvent e) {

because that's the way the method has been declared in the ActionListener interface. When you wrote implements ActionListener in the declaration of your class, you promised to provide implementations of all the methods listed in the ActionListener interface. Fortunately, there's only one such method, but you do need to implement it.

Answer 2

When you extend an abstract class or implement an interface, you need to complete the concrete class definition by providing definition to all those inherited abstract functions.

In this case, you are missing definition to the following method which is declared in ActionListener interface

public void actionPerformed(ActionEvent e)