java - 类 DepartmentChooser 中的构造函数 DepartmentChooser 不能应用于给定类型

Question

我被要求为我的大学创建一个程序，该程序运行良好，直到我遇到 2 个错误，我已经尝试修复它们一段时间了，我阅读了这里的大部分帖子，但不幸的是他们没有不帮我。现在第一个错误是“类 DepartmentChooser 中的构造函数 DepartmentChooser 不能应用于给定类型”第二个是“Registration is not an abstract and dose not override abstract method actionPerformed”

程序包含的类很少，但我附上了其中的一些。

希望你能帮助我，因为截止日期很快。谢谢

部门选择器

//import java.awt.event.*;
import java.awt.Dimension;
import java.util.Iterator;
import java.awt.List;
import java.util.Collection;
import java.awt.Color;
import java.util.ArrayList;
import java.util.Arrays;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JList;
import javax.swing.ListSelectionModel;
import javax.swing.JFrame;
import javax.swing.event.*;

/**
 * Write a description of class DepartmentChooser here.
 * 
 * @author () 
 * @version (19/07/2014)
 */
public class DepartmentChooser extends JPanel implements ListSelectionListener
{
   private static ChooserListener callback;
   private JList Settings;
   private Department[] departments;
   private JFrame frame;
   private String DepartmentCode;
   private String[] adding;
   
   
   public DepartmentChooser (ChooserListener callback, School s)
   {
       super ();
       this.callback = callback;
       
       Collection <Department> x = s.getDepartments ();
       departments = new Department [x.size()];
       String [] adding = new String [x.size()];
       int i = 0;
       
       for (Iterator itr = x.iterator (); itr.hasNext();)
       {
           departments [i] = (Department) itr.next ();
           adding [i] = departments [i].getName();  
           i++;
        }
        
        Settings = new JList (adding);
        Settings.setPreferredSize(new Dimension(400, 100));
        //Settings.SetColor(Color.gray);
        Settings.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        //Settings.addMouseListener(mouseclicks);
        Settings.addListSelectionListener(this);
        Settings.setVisibleRowCount(6);
        add (new JScrollPane (Settings));
    }
    
    public void valueChanged (ListSelectionEvent e)
    {
        if (e.getValueIsAdjusting())
        {
            Department lister = departments [Settings.getSelectedIndex()];
            if (lister == null)
            {
                System.out.println ("Empty");
            }
            else
            {
                callback.tell(lister);
            }
        }
    }
    
    public ChooserListener getCallBack ()
    {
        return this.callback;
    }
    
    public Department [] getDepartments()
    {
        return this.departments;
    }
    
    public void repeat()
    {
        int i = Settings.getSelectedIndex();
        if (i < 0)
        {
            callback.tell(null);
        }
        else
        {
            callback.tell (departments[i]);
        }
    }
    
    public void passThrough (Object o)
    {
        if (o instanceof Department)
        {
            Department list = (Department) o;
            System.out.println(list.getCode());
        }
    }
}
     

这是为了测试它

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

/**
 * Write a description of class DepartmentTester here.
 * 
 * @author () 
 * @version (20/07/2014)
 */
public class DepartmentTester implements ChooserListener 
{
    public DepartmentTester()
    {
        Loader.load();
        School sch = School.get("SCIM");
        DepartmentChooser DepartmentCho = new DepartmentChooser(sch,null);
        JFrame frame = new JFrame ("Department Chooser");
        frame.add (DepartmentCho);
        frame.setVisible(true);
        frame.pack();
    }
    
    public static void main (String [] args)
    {
        new DepartmentTester();
    }
    
    public void tell (Object o)
    {
        System.out.println(((School)o).getName() + "\n");
    }
    
}

最后这是我得到错误的地方

"Registration is not an abstract and dose not override abstract method actionPerformed"

import java.awt.event.*;
import java.awt.Dimension;
import java.util.Iterator;
import java.awt.List;
import java.util.Collection;
import java.awt.Color;
import java.util.ArrayList;
import java.util.Arrays;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JList;
import javax.swing.ListSelectionModel;
import javax.swing.JFrame;
import javax.swing.event.*;

/**
 * Write a description of class DepartmentChooser here.
 * 
 * @author () 
 * @version (19/07/2014)
 */
public class DepartmentChooser extends JPanel implements ListSelectionListener
{
   private static ChooserListener callback;
   private JList Settings;
   private Department[] departments;
   private JFrame frame;
   private String DepartmentCode;
   private String[] adding;
   
   
   public DepartmentChooser (ChooserListener callback, School s)
   {
       super ();
       this.callback = callback;
       
       Collection <Department> x = s.getDepartments ();
       departments = new Department [x.size()];
       String [] adding = new String [x.size()];
       int i = 0;
       
       for (Iterator itr = x.iterator (); itr.hasNext();)
       {
           departments [i] = (Department) itr.next ();
           adding [i] = departments [i].getName();  
           i++;
        }
        
        Settings = new JList (adding);
        Settings.setPreferredSize(new Dimension(400, 100));
        //Settings.SetColor(Color.gray);
        Settings.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        //Settings.addMouseListener(mouseclicks);
        Settings.addListSelectionListener(this);
        Settings.setVisibleRowCount(6);
        add (new JScrollPane (Settings));
    }
    
    public void valueChanged (ListSelectionEvent e)
    {
        if (e.getValueIsAdjusting())
        {
            Department lister = departments [Settings.getSelectedIndex()];
            if (lister == null)
            {
                System.out.println ("Empty");
            }
            else
            {
                callback.tell(lister);
            }
        }
    }
    
    public ChooserListener getCallBack ()
    {
        return this.callback;
    }
    
    public Department [] getDepartments()
    {
        return this.departments;
    }
    
    public void repeat()
    {
        int i = Settings.getSelectedIndex();
        if (i < 0)
        {
            callback.tell(null);
        }
        else
        {
            callback.tell (departments[i]);
        }
    }
    
    public void passThrough (Object o)
    {
        if (o instanceof Department)
        {
            Department list = (Department) o;
            System.out.println(list.getCode());
        }
    }
}

Answer 1

你只需要阅读错误信息:

constructor DepartmentChooser in class DepartmentChooser can not be applied to given types

这意味着您没有将正确的类型传递给 DepartmentChooser 构造函数。事实上，构造函数定义为

public DepartmentChooser (ChooserListener callback, School s)

因此，它需要一个 ChooserListener 作为第一个参数，一个 School 作为第二个参数。而你正在调用它使用

School sch = School.get("SCIM");
DepartmentChooser DepartmentCho = new DepartmentChooser(sch,null);

因此，您传递一个 School 作为第一个参数而不是一个 ChooserListener，并将 null 作为第二个参数。

您没有发布注册代码，但消息也是不言自明的:

Registration is not an abstract and dose not override abstract method actionPerformed

所以您可能将注册类定义为

public class Registration implements ActionListener {
    ...
}

由于您声明该类实现了 ActionListener ，它必须实现 ActionListener 接口(interface)中定义的方法。因此它必须具有以下方法:

@Override
public void actionPerformed(ActionEvent e) {
    ...
}

或者它不应该实现 ActionListener。