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为什么不addActionListener(e - > {...});让它听私人空虚时不起作用? [重复]

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这个问题在这里已有答案:

我现在已经看了很长一段时间,似乎无法找到我正在寻找的答案 . 我曾经工作BlueJ,但是我的新学校正在使用IntelliJ,但并不是所有的东西都以同样的方式工作,就像我记得的那样 .

我有一个 private void tester() ,我正在放入 testButton.addActionListener(e -> {tester();}); . 当我启动程序时,我立即收到错误,但程序仍然打开,但是当我单击按钮时,没有任何反应,但会出现长错误 . 出现的第一个错误是:

线程“main”中的异常java.lang.ArrayIndexOutOfBoundsException:FrameTest中的长度为1的索引1超出范围 . (FrameTest.java:16)在FrameTest.main(FrameTest.java:11)

然后,当我单击按钮时,会出现这个长错误:

线程“AWT-EventQueue-0”中的异常java.lang.ArrayIndexOutOfBoundsException:在FrameTest.lambda $ FrameFrame $ 0(FrameTest.java:47)的FrameTest.tester(FrameTest.java:30)处长度为1的索引超出范围at java.desktop / javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)at java.desktop / javax.swing.AbstractButton $ Handler.actionPerformed(AbstractButton.java:2308)at java.desktop / javax.swing.DefaultButtonModel .fireActionPerformed(DefaultButtonModel.java:405)java.desktop / javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)at java.desktop / javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279) )java.desktop上的java.desktop / java.awt.Component.processMouseEvent(Component.java:6632),java.desktop / java.awt.Component的java.desktop / javax.swing.JComponent.processMouseEvent(JComponent.java:3342) . java.desktop / java.awt.Componen上的java.desktop / java.awt.Container.processEvent(Container.java:2263)中的processEvent(Component.java:6397) java.desktop上的t.dispatchEventImpl(Component.java:5008)java.desktop / java.awt.Container.dispatchEventImpl(Container.java:2321)java.desktop / java.awt.Component.dispatchEvent(Component.java:4840) .desktop / java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)at java.desktop / java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)at java.desktop / java.awt.LightweightDispatcher.dispatchEvent(Container .java:4488)java.desktop上的java.desktop / java.awt.Container.dispatchEventImpl(Container.java:2307)java.desktop / java.awt.Window.dispatchEventImpl(Window.java:2772) . awt.Component.dispatchEvent(Component.java:4840)at java.desktop / java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)at java.desktop / java.awt.EventQueue $ 4.run(EventQueue.java:721 )java.desktop / java.awt.EventQueue $ 4.run(EventQueue.java:715)at java.base / java.security.AccessController.doPrivileged(Native Method)at java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl . doInters ectionPrivilege(ProtectionDomain.java:85)位于java.desktop / java.awt.EventQueue $ 5.run(EventQueue.java:745)的java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95) java.desktop / java.awt.EventQueue $ 5.run(EventQueue.java:743)at java.base / java.security.AccessController.doPrivileged(Native Method)at java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege( ProtectionDomain.java:85)java.desktop上的java.desktop / java.awt.EventQueue.dispatchEvent(EventQueue.java:742)java.desktop / java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) .awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)at java.desktop / java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)at java.desktop / java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109 )在java.desktop / java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.ja) va:101)在java.desktop / java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

我不知道长错误是否有帮助,但想要显示它们 .

这是我的整个代码:

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);
    }
}

2 回答

  • 0

    将String数组的大小增加到适当的长度,例如在你的情况下:

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

    并且为了避免在多次单击按钮(超过11次)后抛出 ArrayIndexOutOfBoundsException ,应检查 tester() 方法中的索引:

    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!
    }
    
  • -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();
            }
        }
    

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