如何使用JLabel在JFrame上添加背景图像？

Question

I am trying to display a background image on the JFrame using a JLabel. The code runs and the buttons appear, but the image does not. I have researched for solutions, yet I have not found one for my code specifically. Any help would be greatly appreciated.

/**
 * Adds details to interface and programs buttons
 * 
 * Imani Davis 
 * Final Project
 */

import java.awt.*;
import java.awt.GridBagLayout;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.ImageIcon;
import javax.swing.border.EmptyBorder;


public class Use_PF_Interface extends JFrame implements Pet_Fish_Interface
{
    // instance variables - replace the example below with your own
    private JFrame window;
    private JPanel panel1, panel2, panel3;
    private JLabel lblBackgroundImage = new JLabel();
    private JButton feedButton = new JButton("Feed Fish");
    private JButton playGamesButton = new JButton("Play Game");

    /**
     * Constructor for objects of class Use_PF_Interface
     */
    public Use_PF_Interface()
    {
        setTitle("Virtual Pet Fish");
        setSize(650, 650);


        //initializes panels and panel layout
        panel1 = new JPanel();
        panel2 = new JPanel();
        panel3 = new JPanel();
        panel1.setLayout(new FlowLayout());
        panel2.setLayout(new FlowLayout());
        panel3.setLayout(new FlowLayout());

        lblBackgroundImage.setLayout(new FlowLayout());

        //sets background image of panel
        lblBackgroundImage.setIcon(new ImageIcon("C:\\Users\\This PC\\Desktop\\OCEAN2.JPEG"));
        panel1.add(lblBackgroundImage);
        validate();

        //adds button to panels
        panel2.add(feedButton);
        panel2.add(playGamesButton);

        //add panels to frame
        add(panel1);
        add(panel2);

    }


}

Answer 1

JFrame uses a BorderLayout by default, a BorderLayout can only manage a single component within any of the five available positions it provides, this means that panel2 is most likely the only component getting shown.

An alternative is to add you components to the JLabel , but remember, JLabel doesn't have a default layout manager. Also, remember, JLabel only uses the icon and text properties to calculate its preferred size, so if the contents require more space, they will be clipped.

Start by having a look at How to Use BorderLayout for more details

Also, remember, most Swing components are opaque generally, so you need to set them transparent when you want to do something like this

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Use_PF_Interface extends JFrame {
    // instance variables - replace the example below with your own

    private JPanel panel2;
    private JLabel lblBackgroundImage = new JLabel();
    private JButton feedButton = new JButton("Feed Fish");
    private JButton playGamesButton = new JButton("Play Game");

    /**
     * Constructor for objects of class Use_PF_Interface
     */
    public Use_PF_Interface() {
        setTitle("Virtual Pet Fish");
        setSize(650, 650);

        //initializes panels and panel layout
        panel2 = new JPanel();
        panel2.setOpaque(false);
        panel2.setLayout(new FlowLayout());

        lblBackgroundImage.setLayout(new FlowLayout());

        //sets background image of panel
        lblBackgroundImage.setIcon(new ImageIcon("..."));
        lblBackgroundImage.setLayout(new BorderLayout());

        //adds button to panels
        panel2.add(feedButton);
        panel2.add(playGamesButton);

        lblBackgroundImage.add(panel2);

        add(lblBackgroundImage);

    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new Use_PF_Interface();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}

Answer 2

Try this,

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;

public class ImageInFrame {
    public static void main(String[] args) throws IOException {
        String path = "Image1.jpg";
        File file = new File(path);
        BufferedImage image = ImageIO.read(file);
        JLabel label = new JLabel(new ImageIcon(image));
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(label);
        f.pack();
        f.setLocation(200,200);
        f.setVisible(true);
    }
}