Question

JAVA中类名不是抽象的,并且未覆盖抽象方法

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

public class ComboBoxFrame extends JFrame{
private String []citys = {"HongKong","Shanghai","Beijing","Xi'an"};
private JComboBox combCity = new JComboBox();
private JButton b = new JButton("Add City");
private JTextField t = new JTextField(15);
private int count = 0;
public ComboBoxFrame(){
setSize(new Dimension(200,175));
combCity.addItem("Shenzhen");
b.addActionListener(new ActionListener(){
public void acitonPerformed(ActionEvent e){
if(count < citys.length){
combCity.addItem(citys[count++]);
}
}
});
combCity.addActionListener(new ActionListener(){
public void acitonPerformed(ActionEvent e){
int index = ((JComboBox)e.getSource()).getSelectedIndex();
t.setText("index:" + index);
}
});

getContentPane().setLayout(new FlowLayout());
getContentPane().add(t);
getContentPane().add(combCity);
getContentPane().add(b);

}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run(){
try{
UIManager.setLookAndFeel(
UIManager.getSystemLookAndFeelClassName());
}catch(Exception exception){
exception.printStackTrace();
}
ComboBoxFrame comboboxframe = new ComboBoxFrame();
comboboxframe.setVisible(true);
}
});
}
}
Comboboxframe.java:14: 错误: <匿名ComboBoxFrame$1>不是抽象的, 并且未覆盖ActionLi
stener中的抽象方法actionPerformed(ActionEvent)
b.addActionListener(new ActionListener(){

注: Comboboxframe.java使用了未经检查或不安全的操作。
注: 有关详细信息, 请使用 -Xlint:unchecked 重新编译。

Answer 1

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

public class ComboBoxFrame extends JFrame{
    private String []citys = {"HongKong","Shanghai","Beijing","Xi'an"};
    private JComboBox combCity = new JComboBox();
    private JButton b = new JButton("Add City");
    private JTextField t = new JTextField(15);
    private int count = 0;
    public ComboBoxFrame(){
        setSize(new Dimension(200,175));
        combCity.addItem("Shenzhen");
        b.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                if(count < citys.length){
                    combCity.addItem(citys[count++]);
                }
            }
        });
        combCity.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                int index = ((JComboBox)e.getSource()).getSelectedIndex();
                t.setText("index:" + index);
            }
        });

        getContentPane().setLayout(new FlowLayout());
        getContentPane().add(t);
        getContentPane().add(combCity);
        getContentPane().add(b);

    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run(){
                try{
                    UIManager.setLookAndFeel(
                        UIManager.getSystemLookAndFeelClassName());
                }catch(Exception exception){
                    exception.printStackTrace();
                }
                ComboBoxFrame comboboxframe = new ComboBoxFrame();
                comboboxframe.setVisible(true);
            }
        });
    }
}

COPY过去运行吧！

追问

咦 我怎么看了是完全一样的呀？不过可以运行

追答

你是手写的吧？哪是一样的？方法名字不一样，就没实现接口方法！

Answer 2

actionPerformed