Java在列表中找不到符号 [英] Java cannot find symbol in List

问题描述

好的，所以我从 JList 切换到 List 因为

OK so I switched from JList to List because

1.) 它不会与我绘制的图像重叠2.) 它可以禁用焦点但跟踪选择的内容

1.) It doesn't overlap my drawn images 2.) It can have focus disabled yet track what's selected

无论如何，这是我尝试编译时遇到的错误:

Anyway, here's the error I get when I try to compile:

C:\Users\Dan\Documents\DanJavaGen\inventory.java:30: cannot find symbol
symbol  : constructor List(java.lang.Object[])
location: class java.awt.List
        list = new List(arr.toArray());
               ^
C:\Users\Dan\Documents\DanJavaGen\inventory.java:50: cannot find symbol
symbol  : method getSelectedValue()
location: class java.awt.List
        Object index = list.getSelectedValue();
                           ^

代码:

import java.applet.Applet;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.io.*;
import java.util.*;
import java.awt.List;

public class inventory extends JApplet implements MouseListener {

public static String newline;
public static List list;
int gold = 123;

    public void init() {



ArrayList<String> arr = new ArrayList<String>();
arr.add("Hatchet");
arr.add("Sword");
arr.add("Shield");
arr.add(gold + " Gold");
System.out.println("You have " + arr.size() + " items in your inventory.");
showInventory(arr);



        list = new List(arr.toArray());

        add(list);

        list.addMouseListener(this);

        list.setVisible(true);

    }

public static void showInventory (ArrayList<String> theList) {
for (int i = 0; i < theList.size(); i++) {
System.out.println(theList.get(i));
}
}


    public void mousePressed(MouseEvent e) { }

    public void mouseReleased(MouseEvent e) {
        Object index = list.getSelectedValue();
       System.out.println("You have selected: " + index);
    }

    public void mouseEntered(MouseEvent e) { }

    public void mouseExited(MouseEvent e) { }

    public void mouseClicked(MouseEvent e) { }




    public void paint(Graphics g) {

    }
}

推荐答案

这里有两个问题:

java.awt.List 没有接受 Object[] 的构造函数:

java.awt.List does not have a constructor that takes Object[]:

list = new List();
for (String item : arr) {
    list.add(item);
}

java.awt.List 有 getSelectedItem() 而不是 getSelectedValue():

您可以将 ArrayList 与 List 如下:

You could your ArrayList with List as follows:

public void mouseReleased(MouseEvent e) {
    Object index = list.getSelectedItem();
    System.out.println("You have selected: " + index);
}

这篇关于Java在列表中找不到符号的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！