Question

我已经环顾了很长时间，但似乎找不到我要找的答案。我曾经在BlueJ上班，但是我的新学校在使用IntelliJ，但并不是所有的工作方式都一样，就像我记得的那样。

我有一个private void tester()，我要放在testButton.addActionListener(e -> {tester();});里面。当我启动程序时，我立即收到错误消息，但是程序仍然打开，但是当我单击按钮时，什么也没有发生，只是出现了很长的错误。出现的第一个错误是：

线程“主”中的异常java.lang.ArrayIndexOutOfBoundsException：索引1超出长度1的范围在FrameTest。（FrameTest.java:16）在FrameTest.main（FrameTest.java:11）

然后，当我单击按钮时，出现此长错误：

线程“ AWT-EventQueue-0”中的异常java.lang.ArrayIndexOutOfBoundsException：索引1超出长度1的范围在FrameTest.tester（FrameTest.java:30）在FrameTest.lambda $ makeFrame $ 0（FrameTest.java:47）在java.desktop / javax.swing.AbstractButton.fireActionPerformed（AbstractButton.java:1967）在java.desktop / javax.swing.AbstractButton $ Handler.actionPerformed（AbstractButton.java:2308）在java.desktop / javax.swing.DefaultButtonModel.fireActionPerformed（DefaultButtonModel.java:405）在java.desktop / javax.swing.DefaultButtonModel.setPressed（DefaultButtonModel.java:262）在java.desktop / javax.swing.plaf.basic.BasicButtonListener.mouseReleased（BasicButtonListener.java:279）在java.desktop / java.awt.Component.processMouseEvent（Component.java:6632）在java.desktop / javax.swing.JComponent.processMouseEvent（JComponent.java:3342）在java.desktop / java.awt.Component.processEvent（Component.java:6397）在java.desktop / java.awt.Container.processEvent（Container.java:2263）在java.desktop / java.awt.Component.dispatchEventImpl（Component.java:5008）在java.desktop / java.awt.Container.dispatchEventImpl（Container.java:2321）在java.desktop / java.awt.Component.dispatchEvent（Component.java:4840）在java.desktop / java.awt.LightweightDispatcher.retargetMouseEvent（Container.java:4918）在java.desktop / java.awt.LightweightDispatcher.processMouseEvent（Container.java:4547）在java.desktop / java.awt.LightweightDispatcher.dispatchEvent（Container.java:4488）在java.desktop / java.awt.Container.dispatchEventImpl（Container.java:2307）在java.desktop / java.awt.Window.dispatchEventImpl（Window.java:2772）在java.desktop / java.awt.Component.dispatchEvent（Component.java:4840）在java.desktop / java.awt.EventQueue.dispatchEventImpl（EventQueue.java:772）在java.desktop / java.awt.EventQueue $ 4.run（EventQueue.java:721）在java.desktop / java.awt.EventQueue $ 4.run（EventQueue.java:715）在java.base / java.security.AccessController.doPrivileged（本机方法）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:85）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:95）在java.desktop / java.awt.EventQueue $ 5.run（EventQueue.java:745）在java.desktop / java.awt.EventQueue $ 5.run（EventQueue.java:743）在java.base / java.security.AccessController.doPrivileged（本机方法）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:85）在java.desktop / java.awt.EventQueue.dispatchEvent（EventQueue.java:742）在java.desktop / java.awt.EventDispatchThread.pumpOneEventForFilters（EventDispatchThread.java:203）在java.desktop / java.awt.EventDispatchThread.pumpEventsForFilter（EventDispatchThread.java:124）在java.desktop / java.awt.EventDispatchThread.pumpEventsForHierarchy（EventDispatchThread.java:113）在java.desktop / java.awt.EventDispatchThread.pumpEvents（EventDispatchThread.java:109）在java.desktop / java.awt.EventDispatchThread.pumpEvents（EventDispatchThread.java:101）在java.desktop / java.awt.EventDispatchThread.run（EventDispatchThread.java:90）

我不知道长错误是否有帮助，但想显示它们。

这是我的完整代码：

import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.*;

public class FrameTest {
    private JFrame frame;
    private JLabel test;
    private String liste[] =  new String[1];
    private int number = 0;
    public static void main (String[] args){
        new FrameTest();
    }
    public FrameTest(){
        makeFrame();
        liste[0] = "[**********]";
        liste[1] = "[*********-]";  //line 16, which caused the exception 
        liste[2] = "[********--]";
        liste[3] = "[*******---]";
        liste[4] = "[******----]";
        liste[5] = "[*****-----]";
        liste[6] = "[****------]";
        liste[7] = "[***-------]";
        liste[8] = "[**--------]";
        liste[9] = "[*---------]";
        liste[10] = "[----------]";
    }

    private void tester(){
        number++;
        test.setText(liste[number]);
    }

    private void makeFrame(){
        frame = new JFrame("Test");
        JPanel contentPane = (JPanel)frame.getContentPane();
        contentPane.setBorder(new EmptyBorder(1, 60, 1, 60));

        contentPane.setLayout(new BorderLayout(12, 12));

        JPanel testPanel = new JPanel();
        testPanel.setLayout(new GridLayout(2, 1));

        test = new JLabel("[**********]");
        testPanel.add(test);

        JButton testButton = new JButton("Test");
        testButton.addActionListener(e -> {tester();});
        testPanel.add(testButton);

        contentPane.add(testPanel, BorderLayout.CENTER);

        frame.pack();

        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        frame.setLocation(d.width/2 - frame.getWidth()/2, d.height/2 - frame.getHeight()/2);
        frame.setVisible(true);
    }
}

Answer 1

将String数组的大小增加到适当的长度，例如在您的情况下：

    private String liste[] =  new String[11]; // can store eleven elements

为避免多次单击按钮（超过11次）后ArrayIndexOutOfBoundsException发出蜂鸣声，应在tester()方法中检查索引：

private void tester(){
    if(number<liste.length) {
        number++;
    }
    test.setText(liste[number]);  //if number is greater than liste.length this would lead to an ArrayIndexOutOfBoundsException!
}

Answer 2

Tester不是ActionListener，它是一个方法。

尝试

addActionlistener(        new ActionListener(){
        @Override
        public void actionPerformed(ActionEvent ae) {
           //put code for what tester does here. 
            tester();
        }
    }

为什么不添加ActionListener（e-> {...}）;在收听私人空白时无法正常工作？

2 个答案: