为什么会发生这种情况?滚动条窗格

Question

我收到这个错误

"线程中的异常"；主"；java.lang.IollegalArgumentException：无效的horizontalScrollBarPolicy位于javax.swing.JScrollPane.setHorizontalScrollBarPolicy(JScrollPane.java:554(在com.company.Main.Main(Main.java:39("；

我到底做错了什么？

import com.sun.org.apache.bcel.internal.generic.JsrInstruction;
import javax.swing.*;
import java.awt.*;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
JPanel panel = new JPanel();
JFrame frame = new JFrame();
//set frame
frame.add(panel);
frame.setSize(700, 700);
frame.setMaximizedBounds(new Rectangle(0,0,1000,1000));
frame.setPreferredSize(new Dimension(1000,1000));
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.setResizable(false);
// create text field
JTextField answer = new JTextField();
answer.setBounds(100, 270,300, 30);
answer.setFont(new Font("default", Font.BOLD, 18));
JLabel input = new JLabel("input");
input.setBounds(100, 240, 80, 40);
input.setFont(new Font("default",Font.ITALIC, 20));
//set panel
panel.setLayout(null);
panel.add(answer);
panel.add(input);
JScrollPane inner_window = new JScrollPane();
panel.add(inner_window);
inner_window.setLayout(null);
inner_window.setBounds(100, 300, 500, 300);
inner_window.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
inner_window.setHorizontalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);

// allows window to open in center (frame.setLocationRelativeTo(null);)
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void SlowPrint(){
}
}

Answer 1

不能将垂直滚动条策略传递给setHorizontalScrollBarPolicy。你可能是指inner_window.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);