Update JFrame contents

Question

How can I update the contents of a JFrame at a button click. I am building a image viewer where a list of photopath will be passed in and the user will have to click on the next or previous button to go back and forth and see the images. How can change the images and update the Jframe Below is my current implementation. I tried to dispose of the current frame and make a new one but that is not what I am looking for... package cs213.photoAlbum.simpleview;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.*;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import model.photoNode;

public class ImageViewer {

    private JFrame frame = new JFrame("Image Viewer");
    private Container pane = frame.getContentPane();
    private JPanel imgViewPanel = new JPanel();
    JSlider slider = new JSlider(0, 100, 100);
    JLabel percent = new JLabel("100%");

    String imageFile = "";

    private class ImageView extends JScrollPane {

        JPanel panel = new JPanel();
        Dimension originalSize = new Dimension();
        Image originalImage;
        JLabel iconLabel;

        public ImageView(ImageIcon icon) {

            this.originalImage = icon.getImage();

            panel.setLayout(new BorderLayout());
            iconLabel = new JLabel(icon);
            panel.add(iconLabel);

            setViewportView(panel);

            originalSize.width = icon.getIconWidth();
            originalSize.height = icon.getIconHeight();
        }

        public void update() {

            int min = slider.getMinimum();
            int max = slider.getMaximum();
            int span = max - min;
            int value = slider.getValue();
            double multiplier = (double) value / span;
            multiplier = multiplier == 0.0 ? 0.01 : multiplier;
            Image scaled = originalImage.getScaledInstance((int) (originalSize.width * multiplier), (int) (originalSize.height * multiplier), Image.SCALE_FAST);
            iconLabel.setIcon(new ImageIcon(scaled));
        }
    }

    ImageView imageView;

    public ImageViewer(String imgFile, final ArrayList<photoNode> list) {

        frame.addWindowListener(new WindowAdapter() {

            public void windowClosing(WindowEvent e) {

                frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
            }
        });

        createAndShowGUI();

        imageFile = imgFile;

        ImageIcon icon = new ImageIcon(imageFile);
        imageView = new ImageView(icon);

        JPanel panel = new JPanel();
        panel.add(new JLabel("Set Image Size: "));
        panel.add(slider);
        panel.add(percent);

        pane.add(panel, BorderLayout.NORTH);
        imgViewPanel.add(imageView);
        pane.add(imgViewPanel, BorderLayout.CENTER);

        slider.addChangeListener(new ChangeListener() {

            public void stateChanged(ChangeEvent e) {
                if (!slider.getValueIsAdjusting()) {
                    percent.setText(slider.getValue() + "%");
                    imageView.update();
                }
            }
        });

        JButton next = new JButton("Next");
        JButton prev = new JButton("Prev");
        pane.add(next, BorderLayout.EAST);
        pane.add(prev, BorderLayout.WEST);

        next.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub

                imgViewPanel.remove(imageView);

                if (list.size() > 0) {

                    for (int i = 0; i < list.size(); i++) {

                        if (list.get(i).fileName.equalsIgnoreCase(imageFile)) {                         

                            if (i + 1 < list.size()) {

                                //frame.dispose();

                                ImageIcon icon = new ImageIcon(list.get(i + 1).fileName);
                                ImageView imageView = new ImageView(icon);

                                imgViewPanel.add(imageView);
                                pane.add(imgViewPanel, BorderLayout.CENTER);

                                imgViewPanel.revalidate();

                                break;

                            }           

                        }                       
                    }                   
                }   

            }

        });


    }

    private void createAndShowGUI() { // Creating the GUI...

        frame.getContentPane().setBackground(Color.WHITE);

        frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        frame.setTitle("PhotoAlbum55");

        frame.pack();
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null);
        frame.setResizable(true);
        frame.setVisible(true);

    }

}

Answer 1

The easiest way to swap images is to display them as ImageIcons in a JLabel and simply call setIcon(...) on the JLabel passing in another ImageIcon. If the images are small enough, you could create a collection of icons, perhaps a List<Icon>, and then move backwards or forwards through the list on next or previous button press.