相关疑难解决方法(0)

每当我键入此代码时，java 总是在类声明语句下加下划线，错误消息是“此处需要接口”。我怎样才能解决这个问题？

package tempconverter;
import javax.swing.*;
import java.awt.event.*;
import java.awt.FlowLayout;
import static java.lang.System.out;
public class TempConverter extends JFrame implements ActionListener, ActionEvent{
        static JFrame f = new JFrame();
        static JTextField enter = new JTextField(3);
        static JButton confirm = new JButton("Convert");

    public static void main(String[] args) {
        f.setLayout(new FlowLayout());
        f.setSize(100, 50);
        f.pack();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(enter); 
        f.add(confirm);
        f.setVisible(true);

    }
    @Override
    public void actionPerformed (ActionEvent e) {
        double toConvert = Float.parseFloat(enter.getText());
        double inF, inK;
        inF = toConvert / 5 * 9 + 32;
        inK = …