How to manipulate the site of Jlabels by having a wallpaper?

Question

I’m trying to make an app that has a wallpaper, but I can’t change the position JButton or JLabel. I can only do it if I don’t have a background.

Follows my code:

public class teste extends JFrame{

public teste(){

JLabel titulo1 = new JLabel("Testes de local1");

JLabel titulo2 = new JLabel("Testes de local2");
//

ImageIcon imagem = new ImageIcon(getClass().getResource("/fotos/1.png"));

JLabel background = new JLabel(imagem);

//
setLayout(new BorderLayout());

background.add(BorderLayout.SOUTH,titulo2);

add(background);

background.setLayout(new FlowLayout());

background.add(titulo1);
//
setVisible(true);

setSize(400, 400);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setTitle("Teste");



}
}

Answer 1

Avoid using JLabel to add background on screen as it is a common component and will not allow you to overlay other components on yourself.

The most recommended way to do this is to create a component of the type Container as JPanel, or that it is a container top level, and overwrite the method paintComponent. In addition to filling the background, it will allow you to add numerous other components and position them as you wish:

import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.Image;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TesteBG extends JFrame {

    public TesteBG() {

        JLabel titulo1 = new JLabel("Testes de local1");

        JLabel titulo2 = new JLabel("Testes de local2");
        //
        BackgroundPanel bgPanel = new BackgroundPanel();
        //
        bgPanel.setLayout(new BorderLayout());

        bgPanel.add(titulo1, BorderLayout.NORTH);

        bgPanel.add(titulo2, BorderLayout.SOUTH);

        setContentPane(bgPanel);

        setSize(400, 400);

        setTitle("Teste");

        setVisible(true);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

    class BackgroundPanel extends JPanel {

        Image imagem;

        public BackgroundPanel() {

            try {

                imagem = ImageIO.read(getClass().getResource("/fotos/1.png"));

            } catch (IOException e) {

                JOptionPane.showMessageDialog(null, "Não foi possivel ler a imagem !");

            }
        }

        @Override
        protected void paintComponent(Graphics g) {

            super.paintComponent(g);

            g.drawImage(imagem, 0, 0, this);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            new TesteBG();
        });
    }
}

Note that it is also recommended to configure this panel as rootPane of the screen through the method setContentPane(). From there, everything you add on the screen should be added to the panel and not directly on the screen, so as not to be parts without background.

There is a more complex but more effective way to apply background image to a screen, without getting stuck to the size of the screen or image, if you want to know how, it is well explained in this answer.