Question

I tried loading images, I found a code and it works well, the code for loading an Image is in the constructor, I tried to move it to a button action, and also to a filechooser. But never load an image. there are no errors in the code, and I tested the clauses using print statements, they show that the clauses are passed.

this is an SSCCE:

The constructor code is separated into two parts Upper and Lower. To demonstrate the problem alternate between these codes by commenting and uncommentting each.

the Lower part will work; it loads the image from the constructor.
the upper part set the JPanels and the JButtons required to load the image from Action code.

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.*;

public class ImgLoadTest extends JPanel implements ActionListener
{

    File file;
    BufferedImage img;
    JButton fileChooserButton;
    JButton showImgButton;
    JPanel imgePanel;
    JPanel widgetPanel;
    JFileChooser fileChooser;

    @Override
    public void paintComponent(Graphics g)
    {
        g.drawImage(img, 0, 60, null);
    }

    public ImgLoadTest()
    {
           //Upper:

//        fileChooser = new JFileChooser();
//
//        fileChooserButton = new JButton("Browse");
//        fileChooserButton.addActionListener(this);
//        showImgButton = new JButton("Show Image");
//        showImgButton.addActionListener(this);
//
//        imgePanel = new JPanel();
//        widgetPanel = new JPanel();
//        this.setLayout(new BorderLayout());
//        widgetPanel.add(fileChooserButton);
//        widgetPanel.add(showImgButton);
//        this.add(imgePanel, BorderLayout.CENTER);
//        this.add(widgetPanel, BorderLayout.EAST);


        /*
         *  try alternating (comment/uncomment) between 
         *  the upper code (in this constructor)
         *  and the lower code below;
         */

          //Lower:

        try
        {
            img = ImageIO.read(new File("D:\\De.JPG"));
        } catch (IOException e)
        {
        }

    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        Object source = e.getSource();
        if (source == fileChooserButton)
        {
            int reternedValue = fileChooser.showOpenDialog(ImgLoadTest.this);

            if (reternedValue == JFileChooser.APPROVE_OPTION)
            {
                file = fileChooser.getSelectedFile();
                try
                {
                    img = ImageIO.read(file);
                    System.out.println("File chooser: Image accepted");
                    this.repaint();

                } catch (IOException err)
                {
                    System.out.println("error " + err);
                }
            } else
            {
                System.out.println("No Image");
            }
        }
        if (source == showImgButton)
        {
            try
            {
                System.out.println("button: Image accepted");
                img = ImageIO.read(new File("D:\\De.JPG"));
                repaint();
            } catch (IOException err)
            {
                System.out.println("No Image");
                System.out.println("error " + err);
            }
        }
    }

    public static void main(String[] args)
    {
        JFrame frame = new JFrame("Image load test");
        frame.setSize(new Dimension(400, 600));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ImgLoadTest imgLoadTest = new ImgLoadTest();
        frame.add(imgLoadTest);
        frame.setVisible(true);
    }
}

Answer 1

Just assigning the BufferedImage img will not make the image appear. You could add a JLabel which contains the image:

JLabel picLabel = new JLabel(new ImageIcon(img));
imgePanel.add(picLabel);
imgePanel.revalidate();
imgePanel.repaint();