Re: Display image selected from JFileChooser

In article
<8fe03a4a-cc5d-403d-baec-0e31d35ce3a0@q12g2000yqj.googlegroups.com>,
 jimmy <jimmy.cullen@gmail.com> wrote:


Again, Lew is more assiduous than I, and ilAn's advice will serve you
better in the long run; but I will make a few observations:

0) Don't invoke pack() until you've added the components.

1) Again, extend Component? I don't see a reason.

2) Again, Swing components should be constructed in the EDT; I've
implemented Runnable as another example of doing so.

3) Invoking super.paintComponent(g) is unnecessary when you paint the
entire content.

4) If you make MyAction a separate class, its constructor needs to know
who gets the selected image. Similarly, MyImage needs a method,
setImgage(), to set the new image for later painting.

5) As an example, I've added the same action to a menu bar.

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class MyImageApp implements Runnable {

    public static void main(String[] args) {
        EventQueue.invokeLater(new MyImageApp());
    }

    @Override
    public void run() {
        JFrame myFrame = new JFrame();
        myFrame.setTitle("Here's my Frame");
        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        MyImage core = new MyImage(myFrame);
        Action myAction = new MyAction(core);
        JButton myButton = new JButton(myAction);
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("File");
        menu.add(new JMenuItem(myAction));
        menuBar.add(menu);
        myFrame.setJMenuBar(menuBar);
        myFrame.add(core, BorderLayout.CENTER);
        myFrame.add(myButton, BorderLayout.SOUTH);
        myFrame.pack();
        myFrame.setLocationRelativeTo(null);
        myFrame.setVisible(true);
    }
}

class MyAction extends AbstractAction {

    MyImage panel;

    public MyAction(MyImage panel) {
        super("Open");
        this.panel = panel;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        JFileChooser fileChooser = new JFileChooser();
        int returnVal = fileChooser.showOpenDialog(fileChooser);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            System.out.println("Image selected: " + file.getPath());
            try {
                BufferedImage image =
                    ImageIO.read(fileChooser.getSelectedFile());
                panel.setImgage(image);
                System.out.println("Image loaded to buffer.");
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        } else {
            System.out.println("File access cancelled by user.");
        }
    }
}

class MyImage extends JPanel {

    private final Window parent;
    BufferedImage image;

    public MyImage(JFrame parent) {
        this.parent = parent;
        this.setPreferredSize(new Dimension(200, 200));
    }

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

    public void setImgage(BufferedImage image) {
        this.image = image;
        setPreferredSize(new Dimension(
            image.getWidth(), image.getHeight()));
        parent.pack();
        parent.setLocationRelativeTo(null);
    }
}

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>