Displaying a PApplet inside a JFrame
This code example demonstrates the combination of PApplet with JFrame, JPanel, JButton and JFileChooser.
A simple Processing Applet, showing some bouncing balls, is displayed and controlled inside a JFrame of a Java Application.
Download the source files
Table Of Contents
Source - class Application
package ch.ethz.caad;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
/**
* A simple demo application launching a Processing Applet
*
* Demonstrates the combination of JFrame, JButton, JFileChooser
* and PApplet.
*
* @author georg munkel
*
*/
public class Application {
public static void main(String[] args) {
//create a frame for the application
final JFrame frame = new JFrame("PApplet in Java Application");
//make sure to shut down the application, when the frame is closed
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//create a panel for the applet and the button panel
JPanel panel = new JPanel();
//create a panel for the buttons
JPanel buttonPanel = new JPanel();
//create an instance of your processing applet
final MyApplet applet = new MyApplet();
//start the applet
applet.init();
//Buttons
//create a button labled "create new ball"
JButton buttonCreate = new JButton("create new ball");
//assing a tooltip
buttonCreate.setToolTipText("creates a new ball ");
//give a name for the command
//if this is not assigned the actionCommand equals the button label
buttonCreate.setActionCommand("create ball");
//create a button lable "load file"
JButton buttonLoad = new JButton("load file");
buttonLoad.setToolTipText("loads a new background image");
//button actions
//the create button is simply linked to the applet
//the action is executed inside applet.actionPerformed()
buttonCreate.addActionListener( applet );
//this action is implemented NOT in the PApplet on purpose
//fileDialogues like to crash a PApplet
//
//if the JFileChooser returns a valid file
//loadBgImage() in MyApplet is executed
buttonLoad.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
JFileChooser chooser = new JFileChooser();
//example of an image fileFilter
//no need to use, just switch it off
chooser.setFileFilter(new MyImageFileFilter());
int returnVal = chooser.showOpenDialog(frame);
if(returnVal == JFileChooser.APPROVE_OPTION) {
System.out.println("You chose to open this file: " +
chooser.getSelectedFile().getName());
//sending the selectedFile to loadBgImage() in the PApplet
applet.loadBgImage( chooser.getSelectedFile() );
}
}
});
//store the two buttons in the button panel
buttonPanel.add(buttonCreate);
buttonPanel.add(buttonLoad);
//store the applet in panel
panel.add(applet);
//store the buttonPanel in panel
panel.add(buttonPanel);
//store the panel in the frame
frame.add(panel);
//assign a size for the frame
//reading the size from the applet
frame.setSize(applet.getSize().width, applet.getSize().height +200);
//display the frame
frame.setVisible(true);
}
}
Source - class MyApplet
package ch.ethz.caad;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.util.ArrayList;
import processing.core.*;
/**
* A simple Processing Demo Applet
*
* Used to demonstrate the combination of JFrame, JButton, JFileChooser
* and PApplet
*
* Moves and displays a list of balls on the applet's screen
* A background image can be loaded
*
* This applet can be used as ActionListener for Java Applications.
* @author georg munkel
*
*/
public class MyApplet extends PApplet implements ActionListener{
//list of all balls
ArrayList <Ball> ballList;
//the background image
PImage bgImg = null;
@Override
public void setup() {
size(400, 300);
ballList = new ArrayList<Ball>();
//creates a first ball
createNewBall();
}
@Override
public void draw() {
//check if the background image is already loaded
//if not, the background is painted white
if (bgImg == null) {
background(255);
} else {
image(bgImg,0,0, width, height);
}
//move and display all balls
for (int i=0; i<ballList.size(); i++) {
Ball ball = ballList.get(i);
ball.move();
ball.display();
}
}
/**
* implementation from interface ActionListener
* method is called from the Application
* the String being compared is the ActionCommand from the button
*/
public void actionPerformed(ActionEvent evt) {
if (evt.getActionCommand().equals("create ball")) {
createNewBall();
} else {
println("actionPerformed(): can't handle " +evt.getActionCommand());
}
}
/**
* this method is called by the ActionListener asigned to
* the JButton buttonLoad in Application
*/
public void loadBgImage(File selectedFile) {
bgImg = loadImage(selectedFile.getAbsolutePath());
}
/*
* creates a new Ball instance and adds it to ballList
*/
private void createNewBall() {
Ball nBall = new Ball();
ballList.add(nBall);
}
/*
* simple inner class Ball
* balls have a position, speed, size and color
* the basic constructor assign random values to all properties
*
* balls can move
* balls can display themselves
*/
private class Ball {
float x;
float y;
float size;
float speedX;
float speedY;
Color color;
private Ball() {
this.size = random(10, 40);
this.x = random(this.size, width-this.size);
this.y = random(this.size, height-this.size);
this.speedX = random(-2, 2) *3;
this.speedY = random(-2, 2) *3;
this.color = new Color(random(1), random(1), random(1));
}
private void move() {
if (x+size/2f > width || x-size/2f < 0) speedX = -speedX;
if (y+size/2f > height || y-size/2f < 0) speedY = -speedY;
x += speedX;
y += speedY;
}
private void display() {
stroke(color.getRGB());
fill(color.getRGB(), 120);
ellipse(x, y, size, size);
}
}
}
Source - class MyImageFileFilter
package ch.ethz.caad;
import java.io.File;
import javax.swing.filechooser.FileFilter;
/**
* Example for a ImageFileFilter
*/
public class MyImageFileFilter extends FileFilter{
/**
* define which file extension is accepted
*/
@Override
public boolean accept(File f) {
if (f.isDirectory()) {
return true;
}
String extension = Utils.getExtension(f);
if (extension != null) {
if (extension.equals(Utils.tiff)
|| extension.equals(Utils.tif)
|| extension.equals(Utils.gif)
|| extension.equals(Utils.jpeg)
|| extension.equals(Utils.jpg)
|| extension.equals(Utils.png)) {
return true;
} else {
return false;
}
}
return false;
}
/**
* define the description of this fileFilter
* for the JFileChooser
*/
@Override
public String getDescription() {
return "ImageFiles";
}
/**
* Simple utility to compare file extensions
*/
private static class Utils {
public final static String jpeg = "jpeg";
public final static String jpg = "jpg";
public final static String gif = "gif";
public final static String tiff = "tiff";
public final static String tif = "tif";
public final static String png = "png";
/*
* Get the extension of a file.
*/
public static String getExtension(File f) {
String ext = null;
String s = f.getName();
int i = s.lastIndexOf('.');
if (i > 0 && i < s.length() - 1) {
ext = s.substring(i+1).toLowerCase();
}
return ext;
}
}
}