JTextArea insert（）不断给出错误

Question

I'm trying to insert JTextArea text in a specified position. But keep getting illegal argument exceptions. Here's the code.

import javax.swing.JTextArea;
import javax.swing.JFrame;
import java.awt.Color;
import javax.swing.JScrollPane;
import java.awt.FlowLayout;
import javax.swing.JButton;
import java.awt.Point;

public class TextWork{
    public static  void main(String[] args)  { 
        JTextArea fnew = new JTextArea(20,20);
        JFrame Main = new JFrame();
        Main.setVisible(true);
        Main.setResizable(true);
        Main.setTitle("Gui");
        Main.setSize(500,500);
        Main.getContentPane().setLayout(null);
        Main.setLocationRelativeTo(null);
        Main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        fnew.insert("Hello",5);
        fnew.setBounds(100,100,100,100); 
        fnew.setEditable(false);
        Main.add(fnew);
    }
}

Answer 1

As per the documentation , if you try to insert text through an index which exceeds the amount of text already present in the component, an exception is thrown.

In short, your text field is empty, so try to insert text at the 5th location exceeds the text field's length. Since this is the first time your are adding text, you might want to use setText("Hello") instead.