I can’t leave Jbutton on Jlabel

Question

I have a JPanel, and within it a JLabel of the same size. The JLabel has an icon associated with it, working like a wallpaper. When I try to put a Jbutton on top of Jlabel, Netbeans repositions the 2. Would anyone know why ?

Already I thank you.

Answer 1

You can add a background directly to JPanel, instead of using a JLabel to do so because all the swing components inherit from JComponent and can therefore be containers of other components, Jbuttons, Jlabels, Jtextfields and some others do not have any implementation of a LayoutManager, which makes components such as JPanel more appropriate for this purpose, as they already have layout implementation.

The class below has been adapted of this link(in Portuguese and very well explained), you have to pass the reference of the image, that the JPanel adapts to her size:

class myCustomPanel extends JPanel {

    private Image background;

    public myCustomPanel(URL path) {
        this.background = new ImageIcon(path).getImage();
        setOpaque(false);
        setPreferredSize(new Dimension(getWidth(), getHeight()));
    }

    @Override
    protected void paintComponent(Graphics g) {
        g.drawImage(background, 0, 0, this);
        super.paintComponent(g);
    }

    @Override
    public int getWidth() {
        return background.getWidth(this);
    }

    @Override
    public int getHeight() {
        return background.getHeight(this);
    }
}

Functional example of the above class, with a JButton added:

package example;

import java.awt.*;
import java.net.*;
import javax.swing.*;

public class BackgroundPanel extends JFrame {

    public BackgroundPanel() throws MalformedURLException {
        //se a imagem estiver no projeto, basta referenciar ela
        // pela localização do pacote
        //ex: URL path = getClass().getResource("caminho/da/suaImage.jpg");
        URL path = new URL("http://www.itinterns.org/wp-content/uploads/2015/09/Java_620X0.jpg");
        JPanel p = new myCustomPanel(path);
        p.add(new JButton("botao"));
        this.add(p);
        this.pack();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    class myCustomPanel extends JPanel {

        private Image background;

        public myCustomPanel(URL path) {
            this.background = new ImageIcon(path).getImage();
            setOpaque(false);
            setPreferredSize(new Dimension(getWidth(), getHeight()));
        }

        @Override
        protected void paintComponent(Graphics g) {
            g.drawImage(background, 0, 0, this);
            super.paintComponent(g);
        }

        @Override
        public int getWidth() {
            return background.getWidth(this);
        }

        @Override
        public int getHeight() {
            return background.getHeight(this);
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    BackgroundPanel b = new BackgroundPanel();
                    b.setLocationRelativeTo(null);
                    b.setVisible(true);
                } catch (MalformedURLException ex) {

                }
            }
        });
    }
}

Resulting: