Java Swing 13 GridLayout does not exist?

Question

I can't seem to get a swing GridLayout to work in java 13. The error is that GridLayout cannot be resolved to a type in the following code:

import javax.swing.*;
public class GameFrame extends JFrame {
    public static final void NewFrame() {
        new GameFrame();
    }
    public GameFrame() {
        this.setSize(1600, 800);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setTitle("The Game");
        this.setVisible(true);
        this.setResizable(false);
        JPanel MainPanel = new JPanel();
        MainPanel.setLayout(new GridLayout());
    }
}

Answer 1

The issue is caused by the class not being imported.

import java.awt.GridLayout;

Since it is not in the swing package it doesn't get imported with the star import. Also it is better to use explicit imports.

Answer 2

This might be related to the fact that panel is empty. Try running this code and it should work.

public class GridLayoutTest {

private static JButton[] arrayBtn;

public static void main(String[] args) {

    // the frame that contains the components
    JFrame frame = new JFrame("GridLayoutTest from JCG");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    // set the size of the frame
    frame.setSize(350, 350);

    // set the rows and cols of the grid, as well the distances between them
    GridLayout grid = new GridLayout(5, 3, 10, 10);
    // what layout we want to use for our frame
    frame.setLayout(grid);

    // add a text field with a specified text to the frame
    JTextArea text = new JTextArea();
    text.setText("Result");
    text.setEditable(false);
    frame.add(text);

    // add buttons to the frame
    frame.add(new JButton("+"));
    frame.add(new JButton("="));

    arrayBtn = new JButton[10];
    // add JButtons dynamically
    for(int i=0; i < arrayBtn.length; i++) {
        arrayBtn[i] = new JButton(Integer.toString(i));
        frame.add(arrayBtn[i]);
    }

    frame.setVisible(true);

}

}