java - 使用 AWT 面板的静态嵌套类下拉列表

Question

免责声明，这是我坚持做的一项家庭作业。请为我指明正确的方向。

我的嵌套类遇到问题。我基本上必须创建一个嵌套静态类，通过 java.AWT Panel 生成下拉列表。

这是代码:(对我的代码进行了轻微更新......仍然很困惑)

package ui.panels;

import interfaces.Resettable;
import java.awt.Choice;
import java.awt.Color;
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import shapes.Shape;
import model.Model;

public class MainPanel extends Panel implements Resettable{
    ActionPanel actionPanel;
    ControlsPanel controlsPanel;
    private ColorPanel colorPanel;

    private void init() {
        colorPanel = new ColorPanel();
    }

    public MainPanel(Model model) {
        actionPanel = new ActionPanel(model);
        controlsPanel = new ControlsPanel(model);

        setLayout(new GridLayout(2,1));
        add(controlsPanel);
        add(actionPanel);

    }

     public void resetComponents() {
         controlsPanel.resetComponents();
         actionPanel.resetComponents();
     }

     public static class ColorPanel {

       public final static String BLACK = "Black";
       public final static String BLUE = "Blue";
       public final static String GREEN = "Green";
       public final static String RED = "Red";
       public final static String YELLOW = "Yellow";
       public final static String Magenta = "Magenta";

       private static String[] color_selections = {"Black","Blue","Green","Red","Yellow","Magenta"};
       String msg = "";

          // now create list panel
          public ColorPanel(){
            Choice myChoice = new Choice();

            for (String msg : color_selections) {
              myChoice.add(msg);
            }
            myChoice.addItemListener(new ItemListener() {
              public void itemStateChanged(ItemEvent e) {

                //do something here when item is selected

              }
          });
            this.add(myChoice); //here is my problem. I don't know what this should say
          }

     }
}

Answer 1

静态嵌套类没有对包含类实例的隐式引用。如果要求使嵌套类静态，则需要在构造函数中提供对包含实例的显式引用。即:

public ColorPanel(Model mdl, MainPanel main)