如何正确调整JFrame中按钮的大小和位置？

Question

I am attempting to make a PC Application using Java and JFrame . I'm trying to format 2 transparent buttons, each sized half of the full screen shown (vertically). The top half of the screen will hold to option to debate someone and the bottom half of the screen will hold the option to spectate a debate if clicked on. Here is what I have so far:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class BackgroundImageJFrame extends JFrame {
   JButton b1;
   JButton b2;
   JPanel j1;
   JPanel j2;

   public BackgroundImageJFrame() {
      setTitle("Background Color for JFrame");
      setSize(340,563);
      setLocationRelativeTo(null);
      setDefaultCloseOperation(EXIT_ON_CLOSE);
      setVisible(true);
      setLayout(null);
/*
    One way
    -----------------
    setLayout(new BorderLayout());
    JLabel background=new JLabel(new ImageIcon("C:\\Users\\Computer\\Downloads\\colorful design.png"));
    add(background);
    background.setLayout(new FlowLayout());
    l1=new JLabel("Here is a button");
    b1=new JButton("I am a button");
    background.add(l1);
    background.add(b1);
*/
// Another way
      setLayout(new BorderLayout());
      setContentPane(new JLabel(new ImageIcon("C:\\Users\\MLH-User\\Downloads\\Front.jpg")));
      setLayout(new FlowLayout());
      j1 = new JPanel();
      j1.setLayout(null);
      b1 = new JButton("Spectate");
      //b1.setBounds(0,0,50,50);
      b1.setOpaque(false);
      b1.setContentAreaFilled(false);
      b1.setBorderPainted(false);
      j1.add(b1);

      b2 = new JButton("Debate");



      b2.setLocation(0,0);
      b2.setOpaque(false);
      b2.setContentAreaFilled(false);
      b2.setBorderPainted(false);
      j1.add(b2);
      add(j1);
    // Just for refresh :) Not optional!
      setSize(339,562);
      setSize(340,563);
    }
    public static void main(String args[])   {
      new BackgroundImageJFrame();
    }
} 

This is some stuff I experimented with so far, can anyone help me out about where I went wrong?

Answer 1

You should use a layout manager. Here is an example with GridLayout :

public class Example extends JFrame {

    private static final int SIZE = 300;

    public Example() {

        setLayout(new GridLayout(2, 1, 0, 5));
        getContentPane().setBackground(Color.WHITE);

        JButton debate = new JButton("DEBATE") {

            public Dimension getPreferredSize() {

                return new Dimension(SIZE, SIZE);
            }
        };
        Font font = debate.getFont().deriveFont(30f);
        debate.setFont(font);
//      debate.setBorderPainted(false);
        debate.setBackground(Color.BLUE.brighter());
        debate.setForeground(Color.WHITE);

        JButton spectate = new JButton("SPECTATE") {

            public Dimension getPreferredSize() {

                return new Dimension(SIZE, SIZE);
            }
        };
        spectate.setFont(font);
//      spectate.setBorderPainted(false);
        spectate.setBackground(Color.RED.brighter());
        spectate.setForeground(Color.WHITE);

        add(debate);
        add(spectate);

        setDefaultCloseOperation(EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }

    public static void main(final String[] args) {

        SwingUtilities.invokeLater(() -> new Example());
    }
}

Notes:

• You have to realize that screen sizes vary. Setting SIZE to 300 was an arbitrary choice for presentation, screens might not have the required size. You can also set the insets or an empty border instead of specifying the size of the component directly.
• You can consider creating a class for these buttons if you have more of them.

Answer 2

This is an example of setting the sizes. I don't know about the location part though.

    JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new GridLayout(4,4,4,4));

for(int i=0 ; i<16 ; i++){
    JButton btn = new JButton(String.valueOf(i));
    btn.setPreferredSize(new Dimension(40, 40));
    panel.add(btn);
}
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);