在ActionListener里面引用点击JButton

Question

我想用swing写一个Tic Tac Toe程序，但是我似乎遇到了一些麻烦。在我的匿名内部类中，我尝试为每个按钮设置actionListener，但是我无法找到允许我引用按钮并将它们设置为X或Y的类型或变量。我尝试了e .getSource（）。setText（）在我的匿名类中，但返回错误。有什么想法吗？ 谢谢！ 亚历

import javax.swing.*; 

import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

public class TicTacToe { 

public JFrame frame; 
public JLabel label; 
public JPanel panel; 

public static int counter; 



public void go() 
{ 
    frame = new JFrame("TicTacToe"); 
    frame.setSize(500, 500); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    panel = new JPanel(); 
    panel.setLayout(new GridLayout(3,3,10,10)); 
    frame.add(BorderLayout.CENTER, panel); 
    label= new JLabel("TIC TAC TOE"); 
    frame.add(BorderLayout.NORTH, label); 

    ; 


    JButton button1 = new JButton("Button 1"); 
    JButton button2 = new JButton("Button 1"); 
    JButton button3 = new JButton("Button 1"); 
    JButton button4 = new JButton("Button 1"); 
    JButton button5 = new JButton("Button 1"); 
    JButton button6 = new JButton("Button 1"); 
    JButton button7 = new JButton("Button 1"); 
    JButton button8 = new JButton("Button 1"); 
    JButton button9 = new JButton("Button 1"); 





    button1.addActionListener(new ActionListener(){ 
     public void actionPerformed(ActionEvent e) 
     { 


     } 
    }); 

    button2.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button3.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button4.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button5.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button6.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button7.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button8.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    button9.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) 
     { 

     } 
    }); 

    panel.add(button1); 
    panel.add(button2); 
    panel.add(button3); 
    panel.add(button4); 
    panel.add(button5); 
    panel.add(button6); 
    panel.add(button7); 
    panel.add(button8); 
    panel.add(button9); 
    frame.setVisible(true); 
    panel.setVisible(true); 

} 


public static void main(String[] args) 
{ 
    TicTacToe gui = new TicTacToe(); 
    gui.go(); 

} 


} 

Answer 1

记住，ActionListener可以在许多不同类型的组件中使用，所以源参考被一般化。你需要转换为回期望值

button9.addActionListener(new ActionListener() { 
    public void actionPerformed(ActionEvent e) 
    { 
     Object source = e.getSource(); 
     if (source instanceof JButton) { 
      JButton btn = (JButton)source; 
      // Go ahead and do what you like 
     } 
    } 
}); 

虽然我知道你ActionListener，因为它代表几乎可以保证该Object的源类型将是一个JButton，我从来不喜欢盲目地转换对象，但是这我

Answer 2

如果您收到错误，那么你应该发布它们，但我假设这是因为你没有断言源对象实际上是一个按钮。对于你正在做的事情有两个直接的解决方案。

第一个是因为您只是为每个按钮添加一个动作侦听器，您可以假定它是动作事件引用的对象。只要注意，按钮要么必须是一个实例变量或声明为final：

button1.addActionListener(new ActionListener(){ 
     @Override 
     public void actionPerformed(ActionEvent e) 
     { 
      button1.setText("X/Y"); 
     } 
    }); 

其次，这将解决您的错误的原因，是声称ActionEvent源对象其实是一个按钮。

button1.addActionListener(new ActionListener() { 
     @Override 
     public void actionPerformed(ActionEvent e) { 
      if (e.getSource() instanceof JButton) { 
       ((JButton) e.getSource()).setText("X/Y"); 
      } 
     } 
    }); 

Answer 3

我经历了和清理你的代码一点点：这是通过检查源是JButton的实例来完成。我不太清楚为什么你的代码有错误，但我没有得到任何答案。我建议，因为你有共同的代码，像我在数组中一样重用它。我还添加了一个boolean在每次点击按钮时在玩家之间切换。

最后，我建议在构造函数中或在构造函数调用的私有方法中设置JFrame（更复杂的用户界面可能有很多代码，并且分解代码是维护代码的好习惯）就像我下面展示的那样。

import javax.swing.*; 

import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

public class TicTacToe { 
    public static final boolean PLAYER_X = false; 
    public static final boolean PLAYER_O = true; 

    public static int counter; 

    private JFrame frame; 
    private JLabel label; 
    private JPanel panel; 
    private JButton[] buttons; 
    private boolean player; 

    public TicTacToe() { 
     frame = new JFrame("TicTacToe"); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

     panel = new JPanel(); 
     panel.setPreferredSize(new Dimension(500, 500)); 
     panel.setLayout(new GridLayout(3, 3, 10, 10)); 
     frame.add(BorderLayout.CENTER, panel); 

     label = new JLabel("TIC TAC TOE"); 
     frame.add(BorderLayout.NORTH, label); 

     /* Set the initial player turn to player X */ 
     player = PLAYER_X; 

     /* Create the JButtons */ 
     buttons = new JButton[9]; 

     /* Loop through and set all of them up */ 
     for (int i = 0; i < buttons.length; i++) { 
      buttons[i] = new JButton(); 
      buttons[i].addActionListener(new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent e) { 
        if (e.getSource() instanceof JButton) { 
         ((JButton)e.getSource()).setText(player ? "O" : "X"); /* Set button text */ 
         player = !player; /* Switch turns */ 
        } 
       } 
      }); 

      /* Add all of the buttons to the panel. */ 
      panel.add(buttons[i]); 
     } 

     /* Pack the frame to the contents. Basically a "fit to contents". */ 
     frame.pack(); 
    } 

    public void go() { 
     frame.setVisible(true); 
     panel.setVisible(true); 
    } 

    public static void main(String[] args) { 
     TicTacToe gui = new TicTacToe(); 
     gui.go(); 
    } 
}