刚学Java,不知道为什么有java.lang.NullPointException

Question

import java.awt.*;
import javax.swing.*;
public class Example1 {
    public static void main(String[] argv)
    {
        var jFrame=new JFrame("Example1");
        jFrame.setSize(500,300);
        JButton[] jButtons=new JButton[5];
        jButtons[0].setText("Up");
        jButtons[1].setText("Left");
        jButtons[2].setText("Center");
        jButtons[3].setText("Right");
        jButtons[4].setText("Down");
        jFrame.add(jButtons[0],BorderLayout.NORTH);
        jFrame.add(jButtons[1],BorderLayout.WEST);
        jFrame.add(jButtons[2],BorderLayout.CENTER);
        jFrame.add(jButtons[3],BorderLayout.EAST);
        jFrame.add(jButtons[4],BorderLayout.SOUTH);
        jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jFrame.setVisible(true);
    }
}

Exception in thread "main" java.lang.NullPointerException
at Example1.main(Example1.java:9)

Process finished with exit code 1

Answer 1

JButton[] jButtons=new JButton[5];
下面加上
for (int i = 0; i < 5; i++)
jButtons[i] = new JButton();

问题解决的话，请点采纳