類型javax.swing.AbstractButton中的方法addActionListener

我正在運行一個已編程的遊戲，但我得到了四個錯誤，都是類javax.swing.AbstractButton中的方法addActionListener不適用於參數（DisplayArea）。我已經確保所有東西都能正確導入，但是我是java的新用戶，可能缺少格式錯誤。類型javax.swing.AbstractButton中的方法addActionListener

GUI.java

import java.awt.BorderLayout; 
import java.awt.Color; 

import javax.swing.JButton; 
import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.AbstractButton; 

public class GUI extends JFrame { 

private JButton bleft; 
private JButton bRight; 
private JButton bUp; 
private JButton bDown; 

private String[] colors; 
private JComboBox colorList; 
public DisplayArea display; 

public GUI() { 

    super("Lab 4: Simple GUI"); 

    setBackground(Color.white); 
    setSize(DisplayArea.SCREEN_SIZE, DisplayArea.SCREEN_SIZE + 50); 
    setResizable(false); 
    setDefaultCloseOperation(EXIT_ON_CLOSE); 

    //Initializes the variable 

    bleft = new JButton("Left"); 
    bRight = new JButton("Right"); 
    bUp = new JButton("Up"); 
    bDown = new JButton("Down"); 

    colors = new String []{"red", "black", "blue", "green"}; 
    colorList = new JComboBox(colors); 

    display = new DisplayArea(); 

    add(display, BorderLayout.CENTER); 

    JPanel buttonpanel = new JPanel(); 
    buttonpanel.add(bleft); 
    buttonpanel.add(bRight); 
    buttonpanel.add(bUp); 
    buttonpanel.add(bDown); 
    buttonpanel.add(colorList); 

    add(buttonpanel, BorderLayout.SOUTH); 

    bleft.addActionListener(display); //ERROR 
    bRight.addActionListener(display); //ERROR 
    bUp.addActionListener(display); //ERROR 
    bDown.addActionListener(display); //ERROR 

} 

public static void main(String [] args) { 

    GUI gui = new GUI(); 
    gui.setVisible(true); 
} 

}

DisplayArea.java

import javax.swing.JPanel; 
import java.awt.Graphics; 
import java.awt.Point; 
import javax.swing.JComboBox; 
import javax.swing.JButton; 
import java.awt.Color; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListene 

public class DisplayArea extends JPanel { 

public static final int SCREEN_SIZE = 500; 
public static final int DELTA = 10; 

private Color currentColor; 
private Point center; 

public DisplayArea(){ 

    setSize(SCREEN_SIZE, SCREEN_SIZE); 
    center = new Point(SCREEN_SIZE/2, SCREEN_SIZE/2); 
    currentColor = Color.RED; 

} 

@Override 
public void paint(Graphics g){ 

    super.paint(g); 
    g.setColor(currentColor); 
    g.fillOval(center.x, center.y, 10, 10); 
} 

public void actionPerformed (ActionEvent e){ 

    if(e.getSource() instanceof JButton) { 

     String cmd = e.getActionCommand(); 

     if(cmd.equals("Left")){ 
      center.x = center.x - DELTA; 
     } else if (cmd.equals("Right")){ 
      center.x = center.x + DELTA; 
     } else if (cmd.equals("Up")){ 
      center.y = center.y + DELTA; 
     } else if (cmd.equals("Down")){ 
      center.y = center.y - DELTA; 
     } 
} 

repaint(); 

} 

}

來源

2016-02-12 Stephanie

'DisplayArea'應該實現'ActionListener'。（即''public class DisplayArea extends JPanel implements ActionListener''）爲了避免這樣的錯誤，在下一次要覆蓋的方法上面放一個'@ Override'註解。 –

謝謝你解決了這個問題 – Stephanie

正如指出的@LuxxMiner，你傳遞到addActionListener值必須是ActionListener類型。一種選擇是宣佈Anonymous內部類如下：

bleft.addActionListener(new AbstractAction() { 
    @Override 
    public void actionPerformed(ActionEvent arg0) { 
     //Do stuff here 
    } 
});

來源

2016-02-12 17:58:14 JackG22

類型javax.swing.AbstractButton中的方法addActionListener

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