Java &引用；不是抽象的，并且不会覆盖ActionListener中的抽象方法actionPerformed（ActionEvent）”；

我不断得到上面的错误，我相信这是一些简单的东西，但我无法找出它，即使在查找后。我在菜单栏上也有一些问题，但我现在不在乎。据我所知，为了返回actionPerformed方法中的所有数字，它不能为空。但是当我把它改为int时，我得到了标题中所述的错误。当它是void而不是int时，错误变为“void时无法返回”

从发布这个问题的其他人看来，他们声明这个问题时似乎没有使用actionlistener，但我想我是这样

    import java.io.*;
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
    import java.text.*;
    import java.util.*;

     public class Widget extends JFrame implements ActionListener
  {
DataOutputStream output;

String[] styleStrings = { "Economy", "Standard", "Advanced", "Exceptional" };
String[] colorStrings = { "Red", "Green", "Blue", "Yellow" };

int economyCount, standardCount, advancedCount, exceptionalCount, redCount, greenCount, blueCount, yellowCount, entryValue;


JPanel economyPanel = new JPanel();
JPanel standardPanel = new JPanel();
JPanel advancedPanel = new JPanel();
JPanel exceptionalPanel = new JPanel();
JPanel redPanel = new JPanel();
JPanel greenPanel = new JPanel();
JPanel bluePanel = new JPanel();
JPanel yellowPanel = new JPanel();

JLabel selectStyle = new JLabel("Select a style: ");
    JComboBox styleList = new JComboBox(styleStrings);

JLabel selectColor = new JLabel("Select a color: ");
    JComboBox colorList = new JComboBox(colorStrings);

JLabel enterAmount = new JLabel("Enter amount: ");
    JTextField enterField = new JTextField(5);

JButton submitButton = new JButton("Submit");

JLabel blankLabel = new JLabel("");

JLabel totalLabel = new JLabel("Total Widgets:");

JLabel economyLabel = new JLabel("Economy: " + economyCount);
JLabel standardLabel = new JLabel("Standard: " + standardCount);
JLabel advancedLabel = new JLabel("Advanced: " + advancedCount);
JLabel exceptionalLabel = new JLabel("Exceptional: " + exceptionalCount);

JLabel redLabel = new JLabel("Red: " + redCount);
JLabel greenLabel = new JLabel("Green: " + greenCount);
JLabel blueLabel = new JLabel("Blue: " + blueCount);
JLabel yellowLabel = new JLabel("Yellow: " + yellowCount);



public static void main(String[] args)
{
    Widget w = new Widget();
    w.setSize(500, 500);
    w.setTitle("ABC Computers Inventory Management System");
    w.setResizable(true);
    w.setLocation(300,300);
    w.setVisible(true);
    w.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public Widget()
{
    Container c = getContentPane();
    c.setLayout((new GridLayout(9,2)));

    FlowLayout rowSetup = new FlowLayout(FlowLayout.LEFT);
        economyPanel.setLayout(rowSetup);
        standardPanel.setLayout(rowSetup);
        advancedPanel.setLayout(rowSetup);
        exceptionalPanel.setLayout(rowSetup);
        redPanel.setLayout(rowSetup);
        greenPanel.setLayout(rowSetup);
        bluePanel.setLayout(rowSetup);
        yellowPanel.setLayout(rowSetup);

    economyPanel.add(economyLabel);

    standardPanel.add(standardLabel);

    advancedPanel.add(advancedLabel);

    exceptionalPanel.add(exceptionalLabel);

    redPanel.add(redLabel);

    greenPanel.add(greenLabel);

    bluePanel.add(blueLabel);

    yellowPanel.add(yellowLabel);

    c.add(selectStyle);
    c.add(selectColor);
    c.add(styleList);
    c.add(colorList);
    c.add(enterAmount);
    c.add(enterField);
    c.add(submitButton);
    c.add(blankLabel);
    c.add(totalLabel);
    c.add(blankLabel);
    c.add(economyPanel);
    c.add(redPanel);
    c.add(standardPanel);
    c.add(greenPanel);
    c.add(advancedPanel);
    c.add(bluePanel);
    c.add(exceptionalPanel);
    c.add(yellowPanel);

    styleList.setSelectedIndex(1);
    styleList.setEditable(false);
    styleList.addActionListener(this);

    colorList.setSelectedIndex(1);
    colorList.setEditable(false);
    colorList.addActionListener(this);

    submitButton.addActionListener(this);

    String filename = "widgettotals";
}

public JMenuBar createMenuBar()
{
    JMenuBar mnuBar = new JMenuBar();
    setJMenuBar(mnuBar);

    JMenu mnuFile = new JMenu("File", true);
        mnuFile.setMnemonic(KeyEvent.VK_F);
        mnuFile.setDisplayedMnemonicIndex(0);
        mnuBar.add(mnuFile);

    JMenuItem mnuFileExit = new JMenuItem("Exit");
        mnuFileExit.setMnemonic(KeyEvent.VK_X);
        mnuFileExit.setDisplayedMnemonicIndex(1);
        mnuFile.add(mnuFileExit);
        mnuFileExit.setActionCommand("Exit");
        mnuFileExit.addActionListener(this);

    JMenu mnuHelp = new JMenu("Help", true);
        mnuHelp.setMnemonic(KeyEvent.VK_E);
        mnuHelp.setDisplayedMnemonicIndex(0);
        mnuBar.add(mnuHelp);

    return mnuBar;
}

public int actionPerformed(ActionEvent e)
{
    economyCount = 0;
    standardCount = 0;
    advancedCount = 0;
    exceptionalCount = 0;
    redCount = 0;
    greenCount = 0;
    blueCount = 0;
    yellowCount = 0;

    String chosenStyle = (String)styleList.getSelectedItem();
    String chosenColor = (String)colorList.getSelectedItem();
    String entryNumbers = enterField.getText();
    int entryValue = Integer.parseInt(entryNumbers);

    if ("Submit".equals(e.getActionCommand()))
    {
        if (styleList.getSelectedItem() == "Economy")
            {
                economyCount = economyCount + entryValue;
            }

        if (styleList.getSelectedItem() == "Standard")
            {
                standardCount = standardCount + entryValue;
            }

        if (styleList.getSelectedItem() == "Advanced")
            {
                advancedCount = advancedCount + entryValue;
            }

        if (styleList.getSelectedItem() == "Exceptional")
            {
                exceptionalCount = exceptionalCount + entryValue;
            }

        if (colorList.getSelectedItem() == "Red")
            {
                redCount = redCount + entryValue;
            }

        if (colorList.getSelectedItem() == "Green")
            {
                greenCount = greenCount + entryValue;
            }

        if (colorList.getSelectedItem() == "Blue")
            {
                blueCount = blueCount + entryValue;
            }

        if (colorList.getSelectedItem() == "Yellow")
            {
                yellowCount = yellowCount + entryValue;
            }
    }

    return economyCount; return standardCount; return advancedCount; return exceptionalCount; 
    return redCount; return greenCount; return blueCount; return yellowCount;
}   
   }

此方法不应返回

int

，或与此相关的任何内容。它应该返回

void

。重写方法时，必须保留相同的签名（只有少数例外-返回类型不是其中之一）

当更改为

void

时，会出现此

错误，因为
void
方法不应返回任何内容，并且您正在尝试返回
int
值。您需要去掉返回的值

最重要的是，你正试图归还一百万件东西。只允许返回一个项/对象/值

如果您试图返回的那些值被认为对ui的其余部分有影响，那么在
actionPerformed
方法中进行这些更改


旁注：


看看能不能帮你解决这个问题

if (styleList.getSelectedItem() == "Economy")


使用
@Override
注释，以便知道是否正确地重写了方法。如果您没有，并且正在实现一个接口（即“ActionListener”），并且您的类不是抽象的，那么您将得到当前收到的错误

@Override
public void actionPerformed(ActionEvent e) {}


非常感谢您迄今为止的帮助，我已经将==改为.equals（），并删除了所有返回值。但是我有一个问题，当你说“在actionPerformed方法中进行那些更改”时，你的意思是将代码从Widget（）方法移动到actionPerformed方法中吗？再次感谢您的帮助。除非我知道您通过返回这些值试图实现的目标，否则我无法回答您的问题。你期望发生什么？好的，我知道你想做什么。使用
label.setText（）
。增加计数后，只需在相应标签上使用
setText
。比如
economyCount=economyCount+entryValue；economyLabel.setText（“经济：+economyCount”）并对所有其他标签执行该操作。不需要返回任何完美的东西！这正是我所需要的，我以为事情会比这复杂得多。你是救命恩人！
@Override
public void actionPerformed(ActionEvent e) {}