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Painting with paintComponent in Java

I have a problem with my code.
We have to code a Game called "Mühle" as our project for this semester.
My problem is, that I want to draw my game token on the field and it does not work although the tokens are added to the board and you can click them but they are not visible and I don't know what I can do.
This is the important part frow my GUI Class:
public class GUIMühle extends JFrame {
static JLabel spieler1, spieler2;
static JFrame frame;
static JButton[] button;
static JButton btnReset;
static int x, y;
static int gewinner = 0;
static int player = 2;
static Buttons[] buttons;
static Steine[] steine1;
static Steine[] steine2;
public GUIMühle(){
InitUI();
}
private void InitUI(){
MouseEvents ME = new MouseEvents();
frame = new JFrame("Mühle");
frame.setSize(960, 540);
frame.setLocationRelativeTo(null);
frame.setLayout(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setBackground(Color.CYAN);
frame.setResizable(false);
DrawSpielbrett spielbrett = new DrawSpielbrett();
spielbrett.setBounds(0,0,960,540);
spielbrett.setVisible(true);
frame.add(spielbrett);
spieler1 = new JLabel("Spieler 1");
spieler1.setBounds(590, 50, 150, 35);
spieler1.setFont(new Font("Arial", Font.BOLD, 30));
frame.add(spieler1);
spieler2 = new JLabel("Spieler 2");
spieler2.setBounds(785, 50, 150, 35);
spieler2.setFont(new Font("Arial", Font.BOLD, 30));
frame.add(spieler2);
// Spielsteine
steine1 = Steine.Erstellen(Color.white, 9, 665, 85);
steine2 = Steine.Erstellen(Color.black, 9, 860, 85);
DrawSteine[] drawSteine1 = new DrawSteine[9];
DrawSteine[] drawSteine2 = new DrawSteine[9];
for(int i = 0; i < steine1.length; i++){
steine1[i].setBounds(steine1[i].getX(),steine1[i].getY(),30,30);
steine1[i].addMouseListener(ME);
steine1[i].setVisible(true);
frame.add(steine1[i]);
}
for(int i = 0; i < steine2.length; i++){
steine2[i].setBounds(860,85+(i*32),30,30);
steine2[i].addMouseListener(ME);
frame.add(steine2[i]);
}
And this is the part from my game token class:
public class Steine extends JLabel{
private Color farbe;
private int x;
private int y;
public Steine(Color farbe, int x, int y){
this.farbe = farbe;
this.x = x;
this.y = y;
}
public static Steine[] Erstellen(Color farbe, int anzahl, int x, int y){
Steine[] steine = new Steine[anzahl];
for(int i = 0; i < steine.length; i++){
steine[i] = new Steine(farbe,x,y);
y = y + 32;
}
return steine;
}
protected void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(this.farbe);
g.fillOval(this.x, this.y, 30, 30);
repaint();
}
/*public static void DrawSteine(Steine stein){
GUIMühle.frame.add(stein);
}*/
public Color getFarbe() {
return this.farbe;
}
#Override
public int getX() {
return this.x;
}
public void setX(int x) {
this.x = x;
}
#Override
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
I hope somebody can help me with this problem.
Thank you in advance.

Generating specific shapes with random dimensions using a JComboBox to select shapes

I am trying to create a program that uses a JComboBox containing specific shapes (Circle, Square, Oval, Rectangle). After the user clicks on a specified shape, the Panel will display 20 of that shape in random dimensions and locations.
I am having trouble on how to make the shapes have random dimensions and locations. Here is my code so far. Any advice or sources to look at would be appreciated.
Thank you.
import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
public class HW1b extends JFrame
{
public HW1b()
{
super("Shapes");
final ComboPanel comboPanel = new ComboPanel();
String[] shapeItems = {"Circle", "Square", "Oval", "Rectangle"};
JComboBox shapeBox = new JComboBox<String>(shapeItems);
shapeBox.addItemListener(new ItemListener()
{
public void itemStateChanged(ItemEvent ie)
{
if (ie.getStateChange() == ItemEvent.SELECTED)
{
String item = (String)ie.getItem();
if(shapeBox.getSelectedItem().equals("Circle"))
comboPanel.makeCircles();
if(shapeBox.getSelectedItem().equals("Square"))
comboPanel.makeSquares();
if(shapeBox.getSelectedItem().equals("Oval"))
comboPanel.makeOvals();
if(shapeBox.getSelectedItem().equals("Rectangle"))
comboPanel.makeRectangles();
}
}
});
JPanel southPanel = new JPanel();
southPanel.add(shapeBox);
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().add(comboPanel, "Center");
getContentPane().add(southPanel, "South");
setSize( 400, 400 );
setLocation( 200, 200 );
setVisible( true );
}
private class ComboPanel extends JPanel
{
int w, h;
Random rand;
static final int OVAL = 0;
static final int RECTANGLE = 1;
int shapeType = -1;
public ComboPanel()
{
rand = new Random();
setBackground(Color.white);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int width = getWidth();
int height = getHeight();
int x, y;
Shape s = null;
for (int i = 0; i < 20; i++)
{
x = rand.nextInt(width - w);
y = rand.nextInt(width - h);
switch(shapeType)
{
case OVAL: s = new Ellipse2D.Double(x,y,w,h);
break;
case RECTANGLE: s = new Rectangle2D.Double(x,y,w,h);
break;
}
if (shapeType > -1)
g2d.draw(s);
}
}
public void makeCircles()
{
shapeType = OVAL;
w = 75;
h = 75;
repaint();
}
public void makeSquares()
{
shapeType = RECTANGLE;
w = 50;
h = 50;
repaint();
}
public void makeOvals()
{
shapeType = OVAL;
w = 80;
h = 60;
repaint();
}
public void makeRectangles()
{
shapeType = RECTANGLE;
w = 80;
h = 40;
repaint();
}
}
public static void main(String[] args)
{
new HW1b();
}
}

You're hard-coding w and h in your code, and so there's no way for this to vary among your shapes. Instead of doing this, use your Random variable, rand, to select random w and h values that are within some desired range. Myself, I wouldn't create my shapes within the paintComponent method since painting is not fully under my control and can occur when I don't want it to. For instance, in your code, your shapes will vary tremendously if the GUI is resized. Instead I'd create a collection such as an ArrayList<Shape> and fill it with created Shape objects (i.e., Ellipse2D for my circles) when desired, and then iterate through that collection within your paintComponent method, drawing your shapes.
for example...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
public class SomeShapes extends JPanel {
private ShapePanel shapePanel = new ShapePanel();
private JComboBox<MyShape> myShapeCombo = new JComboBox<>(MyShape.values());
public SomeShapes() {
myShapeCombo.setSelectedIndex(-1);
myShapeCombo.addItemListener(new ComboListener());
JPanel bottomPanel = new JPanel();
bottomPanel.add(myShapeCombo);
setLayout(new BorderLayout());
add(shapePanel, BorderLayout.CENTER);
add(bottomPanel, BorderLayout.PAGE_END);
}
private class ComboListener implements ItemListener {
#Override
public void itemStateChanged(ItemEvent e) {
MyShape myShape = (MyShape) e.getItem();
shapePanel.drawShapes(myShape);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("SomeShapes");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SomeShapes());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
enum MyShape {
OVAL("Oval"), RECTANGLE("Rectangle"), SQUARE("Square"), CIRCLE("Circle");
private String name;
private MyShape(String name) {
this.name = name;
}
public String getName() {
return name;
}
#Override
public String toString() {
return getName();
}
}
class ShapePanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private static final Color SHAPE_COLOR = Color.BLUE;
private static final int SHAPE_COUNT = 20;
private static int MIN = 5;
private static int MAX = 200;
private List<Shape> shapeList = new ArrayList<>();
private Random random = new Random();
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
public void drawShapes(MyShape myShape) {
shapeList.clear(); // empty the shapeList
switch (myShape) {
case OVAL:
drawOval();
break;
case RECTANGLE:
drawRectangle();
break;
// etc...
default:
break;
}
repaint();
}
private void drawOval() {
// for loop to do this times SHAPE_COUNT(20) times.
for (int i = 0; i < SHAPE_COUNT; i++) {
// first create random width and height
int w = random.nextInt(MAX - MIN) + MIN;
int h = random.nextInt(MAX - MIN) + MIN;
// then random location, but taking care so that it
// fully fits into our JPanel
int x = random.nextInt(getWidth() - w);
int y = random.nextInt(getHeight() - h);
// then create new Shape and place in our shapeList.
shapeList.add(new Ellipse2D.Double(x, y, w, h));
}
}
private void drawRectangle() {
// .... etc
}
//.. .. etc
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
// set rendering hints for smooth ovals
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(SHAPE_COLOR);
// iterate through the shapeList ArrayList
for (Shape shape : shapeList) {
g2d.draw(shape); // and draw each Shape it holds
}
}
}

Adding ViewPort to JPanel

I would like to achieve the following for my swing project,
I was able to get this by extending a JPanel and and using JLayer.
I event tried using AlphaComposite but it didn't work.
Edit1: I think JTable or JViewport might help me to get what I want but I don't know how to use them.
Edit2: Updated the SSCCE, thank you trashgod for the suggestion.
I have made use of the Scalr library because after using getScaledInstance method of Image class, if i tried to use the getSubImage method of BufferedImage,the following exception is thrown:
java.lang.ClassCastException: sun.awt.image.ToolkitImage cannot be
cast to java.awt.image.BufferedImage
since the Image generated by getScaledInstance method is a instance of ToolkitImage so, it cannot be cast into a BufferedImage.
If you don't want to use the Scalr library,you can use the code suggested in this post to scale the BufferedImage and than use getSubImage method.
SCSE.java
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.util.Random;
import javax.swing.*;
import javax.swing.plaf.LayerUI;
import org.imgscalr.Scalr;
public class SCSE {
private JFrame mainFrame;
private JPanel mainPanel;
private GridView gridView;
private JButton imgBtn, shuffleBtn;
private int gridX = -1, gridY = -1, gridWidth = -1, gridHeight = -1;
private boolean isGridEmpty = false;
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
SCSE sc = new SCSE();
sc.createGUI();
});
}
private void createGUI() {
mainFrame = new JFrame();
mainFrame.setSize(500, 500);
mainFrame.setResizable(false);
mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
mainPanel = new JPanel(new BorderLayout());
gridView = new GridView();
imgBtn = new JButton("Get-Image");
shuffleBtn = new JButton("Shuffle-ViewPort");
imgBtn.addActionListener((ActionEvent evt) -> {
try {
gridView.setImage(ImageIO.read(new URL("http://www.keenthemes.com/preview/metronic/theme/assets/global/plugins/jcrop/demos/demo_files/image1.jpg")));
} catch (IOException ex) {
System.out.println(ex);
}
});
shuffleBtn.addActionListener((ActionEvent evt) -> {
gridView.startShuffle();
});
mainPanel.add(gridView.getComponent(), BorderLayout.CENTER);
mainPanel.add(imgBtn, BorderLayout.NORTH);
mainPanel.add(shuffleBtn, BorderLayout.SOUTH);
mainFrame.add(mainPanel);
mainFrame.setLocationRelativeTo(null);
mainFrame.setVisible(true);
}
class GridView {
private Random shuffleRandom;
private RegisterUI layerUi = null;
private JLayer<JPanel> gridLayer = null;
private ImagePanel mainPanel = null;
private int gridNos = 21; //number of grids
int digit[];
private int viewportDimensions = 4; //no of rows and columns in viewport
private JLabel gridLabel[][] = new JLabel[gridNos][gridNos];
private int gridX = -1, gridY = -1, gridWidth = -1, gridHeight = -1;
private boolean isGridInitialized = false;
public GridView() {
initPersuasive();
initPanel();
initGrids();
}
private void initPanel() {
mainPanel = new ImagePanel();
mainPanel.setLayout(new GridLayout(gridNos, gridNos, 0, 0)); //creates layout to place labels in grid form
layerUi = new RegisterUI();
gridLayer = new JLayer<>(mainPanel, layerUi);
}
private void initGrids() {
for (int i = 0; i < gridNos; i++) {
for (int j = 0; j < gridNos; j++) {
gridLabel[i][j] = new JLabel();
gridLabel[i][j].setOpaque(false);
gridLabel[i][j].setName("" + (i + 1)); // Since for loop index is 0 to 80, we add 1 to the name to make it 1 to 81
mainPanel.add(gridLabel[i][j]); //add it to mainPanel
}
}
}
private void initPersuasive() {
shuffleRandom = new Random();
digit = new int[2];
}
private void random() {
digit[0] = shuffleRandom.nextInt(gridNos - viewportDimensions);
digit[1] = shuffleRandom.nextInt(gridNos - viewportDimensions);
}
public void startShuffle() {
random();
int x = gridLabel[digit[0]][digit[1]].getX();
int y = gridLabel[digit[0]][digit[1]].getY();
layerUi.placeViewport(x, y);
}
public void stopShuffle() {
layerUi.removeViewPort();
}
public void setupGridView() {
gridX = gridLabel[0][0].getX();
gridY = gridLabel[0][0].getY();
gridWidth = gridLabel[0][0].getWidth();
gridHeight = gridLabel[0][0].getHeight();
mainPanel.setValues(gridX, gridY);
layerUi.setViewSize(gridWidth * viewportDimensions, gridHeight * viewportDimensions);
}
public void setImage(BufferedImage img) {
if (!isGridInitialized) {
setupGridView();
isGridInitialized = true;
}
BufferedImage sendImg = Scalr.resize(img, Scalr.Mode.FIT_EXACT, gridWidth * gridNos, gridHeight * gridNos, Scalr.OP_ANTIALIAS);
layerUi.setupViewport(img);
mainPanel.paintImage(img);
}
public JLayer<JPanel> getComponent() {
return gridLayer;
}
}
class RegisterUI extends LayerUI<JPanel> {
private int viewX, viewY, viewWidth, viewHeight;
private boolean shuffleIsRunning = false;
private BufferedImage viewportImage = null;
private void drawPCCP(Graphics g, int w, int h) {
Graphics2D g2 = ((Graphics2D) g);
Color c = new Color(1.0f, 1.0f, 1.0f, 0.7f);
g2.setPaint(c);
g2.fillRect(0, 0, w, h);
BufferedImage highlightGrid = Scalr.pad(Scalr.crop(viewportImage, viewX, viewY, viewWidth, viewHeight), 2, Color.BLACK, Scalr.OP_ANTIALIAS);
g2.drawImage(highlightGrid, viewX, viewY, null);
g2.dispose();
}
public void paint(Graphics g, JComponent c) {
super.paint(g, c);
int w = c.getWidth();
int h = c.getHeight();
if (shuffleIsRunning) {
drawPCCP(g, w, h);
}
}
public void setupViewport(BufferedImage bi) {
viewportImage = bi;
}
public void setViewSize(int w, int h) {
viewWidth = w;
viewHeight = h;
}
public void placeViewport(int x, int y) {
viewX = x;
viewY = y;
if (!shuffleIsRunning) {
shuffleIsRunning = true;
}
firePropertyChange("shuffleui", 0, 1);
}
public void removeViewPort() {
if (!shuffleIsRunning) {
return;
}
viewX = 0;
viewY = 0;
viewWidth = 0;
viewHeight = 0;
shuffleIsRunning = false;
firePropertyChange("shuffleui", 0, 1);
}
#Override
public void applyPropertyChange(PropertyChangeEvent evt, JLayer<? extends JPanel> l) {
if ("disableui".equals(evt.getPropertyName()) || "shuffleui".equals(evt.getPropertyName())) {
l.repaint();
}
}
}
class ImagePanel extends JPanel {
private BufferedImage displayImage = null;
private int x, y;
public void setValues(int x, int y) {
this.x = x;
this.y = y;
}
public void paintImage(BufferedImage bi) {
System.out.print(bi);
displayImage = bi;
repaint(); // repaint calls paintComponent method internally
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(displayImage, x, y, this); // To Paint the image on the panel
}
}
}

Instead of using AlphaComposite directly, as shown here, try RescaleOp to alter the image's color/alpha bands, as shown in this example. This will allow you to mute the tone of the entire image as desired. Copy a portion of the original image using getSubimage() to restore the highlight.

JPanel size is not known on start

When I create a Board instance from my Square instance, I try to assign the size of the window to the integers x and y. I fail to do this because it seems like on start the size is 0. In the constructor in Board.java, x and y shouldn't be -50 like they end up now.
Square.java:
package Square;
import javax.swing.*;
public class Square extends JFrame {
public Square(){
add(new Board());
setSize(800, 800);
setVisible(true);
}
public static void main(String[] args){
new Square();
}
}
Board.java
package Square;
import javax.swing.*;
import java.awt.*;
public class Board extends JPanel{
int x,y;
public Board(){
x = width-50;
y = height-50;
}
public int width = (int) getSize().getWidth();
public int height = (int) getSize().getHeight();
public void paintComponent(Graphics g){
super.paintComponent(g);
g.fillRect(x,y, 100, 100);
}
}
Full Code for clarification:
Square.java
package Square;
import javax.swing.*;
public class Square extends JFrame {
public Square(){
Board board = new Board();
board.start();
add(board);
setTitle("Square");
setSize(800, 800);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
public static void main(String[] args){
Square square = new Square();
square.setVisible(true);
square.setLocation(2000, 150);
}
}
Board.java
package Square;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Board extends JPanel implements ActionListener{
Timer timer;
int x, y;
int velX = 0;
int velY = 0;
public Board(){
setFocusable(true);
timer = new Timer(1, this);
addKeyListener(new TAdapter());
}
class TAdapter extends KeyAdapter{
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
switch(keyCode){
case KeyEvent.VK_ESCAPE: x = width()/2-50; y = height()/2-50; break;
case KeyEvent.VK_RIGHT: velX = 1; break;
case KeyEvent.VK_DOWN: velY = 1; break;
case KeyEvent.VK_LEFT: velX = -1; break;
case KeyEvent.VK_UP: velY = -1; break;
}
}
public void keyReleased(KeyEvent e){
velX = 0;
velY = 0;
}
}
public int width(){ return (int) getSize().getWidth();}
public int height(){ return (int) getSize().getHeight();}
public void start(){
timer.setInitialDelay(100);
timer.start();
x = width()/2-50;
y = height()/2-50;
}
#Override
public void actionPerformed(ActionEvent e) {
x += velX;
y += velY;
repaint();
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.RED);
g.fillRect(x,y, 100, 100);
}
}

Put the calculation into your paintComponent method. In general you want to avoid having code in paintComponent that will slow it down, but these calls shouldn't give too much penalty. Also, if your program is re-sizable, you'll need to be able to re-calculate the sizes of things on the go like this:
public void paintComponent(Graphics g){
super.paintComponent(g);
int x = getWidth() - 50;
int y = getHeight() - 50;
g.fillRect(x, y, 100, 100);
}
but of course in your real program, you will want to avoid "magic" numbers
Another issue: don't call setSize() on your JFrame. Instead, if you want to specify a hard size, do so in the JPanel by overriding its getPreferredSize() method. This will also then give you the suggested parameters that can be used for your calculations.
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
#SuppressWarnings("serial")
public class DrawRect extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = PREF_W;
private static final int DELTA = 50;
private static final Color RECT_COLOR = Color.red;
private static final int RECT_WIDTH = 100;
private static final int TIMER_DELAY = 15;
private int rectX = PREF_W - DELTA;
private int rectY = PREF_H - DELTA;
public DrawRect() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(RECT_COLOR);
g.fillRect(rectX, rectY, RECT_WIDTH, RECT_WIDTH);
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
rectX--;
rectY--;
repaint();
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("DrawRect");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new DrawRect());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Also, check out the key bindings animation code from this answer of mine.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.EnumMap;
import java.util.HashMap;
import java.util.Map;
public class GamePanel extends JPanel {
private static final int ANIMATION_DELAY = 15;
private final int HEIGHT = 400;
private final int WIDTH = 600;
private Square square;
private EnumMap<Direction, Boolean> dirMap = new EnumMap<>(Direction.class);
private Map<Integer, Direction> keyToDir = new HashMap<>();
// !! private Circle circle;
private Timer animationTimer;
public GamePanel() {
for (Direction dir : Direction.values()) {
dirMap.put(dir, Boolean.FALSE);
}
keyToDir.put(KeyEvent.VK_UP, Direction.UP);
keyToDir.put(KeyEvent.VK_DOWN, Direction.DOWN);
keyToDir.put(KeyEvent.VK_LEFT, Direction.LEFT);
keyToDir.put(KeyEvent.VK_RIGHT, Direction.RIGHT);
// !! addKeyListener(new DirectionListener());
setKeyBindings();
setBackground(Color.white);
setPreferredSize(new Dimension(WIDTH, HEIGHT));
setFocusable(true);
square = new Square();
animationTimer = new Timer(ANIMATION_DELAY, new AnimationListener());
animationTimer.start();
}
private void setKeyBindings() {
int condition = WHEN_IN_FOCUSED_WINDOW;
final InputMap inputMap = getInputMap(condition);
final ActionMap actionMap = getActionMap();
boolean[] keyPressed = { true, false };
for (Integer keyCode : keyToDir.keySet()) {
Direction dir = keyToDir.get(keyCode);
for (boolean onKeyPress : keyPressed) {
boolean onKeyRelease = !onKeyPress; // to make it clear how bindings work
KeyStroke keyStroke = KeyStroke.getKeyStroke(keyCode, 0,
onKeyRelease);
Object key = keyStroke.toString();
inputMap.put(keyStroke, key);
actionMap.put(key, new KeyBindingsAction(dir, onKeyPress));
}
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
square.display(g);
}
private class AnimationListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent evt) {
boolean repaint = false;
for (Direction dir : Direction.values()) {
if (dirMap.get(dir)) {
square.move(dir);
repaint = true;
}
}
if (repaint) {
repaint();
}
}
}
private class KeyBindingsAction extends AbstractAction {
private Direction dir;
boolean pressed;
public KeyBindingsAction(Direction dir, boolean pressed) {
this.dir = dir;
this.pressed = pressed;
}
#Override
public void actionPerformed(ActionEvent evt) {
dirMap.put(dir, pressed);
}
}
private static void createAndShowGUI() {
GamePanel gamePanel = new GamePanel();
JFrame frame = new JFrame("GamePanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(gamePanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
gamePanel.requestFocusInWindow();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
enum Direction {
UP(0, -1), DOWN(0, 1), LEFT(-1, 0), RIGHT(1, 0);
private int incrX;
private int incrY;
private Direction(int incrX, int incrY) {
this.incrX = incrX;
this.incrY = incrY;
}
public int getIncrX() {
return incrX;
}
public int getIncrY() {
return incrY;
}
}
class Square {
private int x = 0;
private int y = 0;
private int w = 20;
private int h = w;
private int step = 1;
private Color color = Color.red;
private Color fillColor = new Color(255, 150, 150);
private Stroke stroke = new BasicStroke(3f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND);
public void display(Graphics g) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(fillColor);
g2d.fillRect(x, y, w, h);
g2d.setStroke(stroke);
g2d.setColor(color);
g2d.drawRect(x, y, w, h);
g2d.dispose();
}
public void setStep(int step) {
this.step = step;
}
public void move(Direction dir) {
x += step * dir.getIncrX();
y += step * dir.getIncrY();
}
}

Hey your codestyle is horrible, but i try to help :). You can't get a size of an undrawn window. First Things first, your Constructor is wrong, you add the Board that actually create the Board Obj. Calling the Constructor of Board, which has no drawn parent yet and no x,y set. Try to initialize your variables in the Constructor. So just use width and height and fill the values in the constructor. Next, just tell your board its creation size by passing its parent size trough constructor variables.
I think you try to learn java and this is much more elegant. Furthermore, try to do all parent modification before adding some to it. So first setSize, add some Layout (Border/Flow/whatuwish) then get the frames ContentPane and add your Board component. To make things clear, you can't get e.g. the parent and parent size in Contructor because your board Obj isn't created and added yet. If you wish to getParent() and its size, create the Object add it to JFrame and than you can call getParent().getSize(). You get 0 because your JPanel isn't drawn at this time (before creation). If you wish to get the Parent Size just pass the JFrame Ref to Constructor or its size. Another Advise, don't create things in things in things, keep in mind with your code you create your JPanel as first Obj... Here is some example code:
Square:
public class Square extends JFrame {
public static void main(String[] args){
Square square = new Square();
square.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Dimension d = new Dimension(800,800);
square.setPreferredSize(d);
square.setSize(d);
//too much, every Jframe has BorderLayout enabled
square.getContentPane().setLayout(new BorderLayout());
square.getContentPane().add(new Board(square), BorderLayout.CENTER);
square.pack();
square.setVisible(true);
}
}
Board:
public class Board extends JPanel{
int x,y;
JFrame parent;
public Board(JFrame parent){
int width = parent.getPreferredSize().width;
int height = parent.getPreferredSize().height;
x = width-50;
y = height-50;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.fillRect(x,y, 100, 100);
}
}

You can take x and y values after the panel has become visible, in the next EDT cycle, by using SwingUtilities.invokeLater, for example.

Java JScrollBar Design

I want customize the JScrollBar Design. I use Mac to develop the app with eclipse. I already tried to scrollPane.getVerticalScrollBar().setBackground(Color.BLACK); but nothing happen.
My code:
scrollPane = new JScrollPane(scriptView);
scrollPane.setBorder(BorderFactory.createEmptyBorder());
scrollPane.getVerticalScrollBar().setUnitIncrement(6);
window.getContentPane().add(scrollPane);
The Object scriptView is from the class JEditorPane.
How it should look:
Thanks for every help.

I guess you are looking for a transparent scrollbar.
This is just presented as an idea(NOT tested code):
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.plaf.basic.*;
public class TranslucentScrollBarTest {
public JComponent makeUI() {
JTextArea cmp = new JTextArea();
String str = "1234567890abcdefghijklmnopqrstuvwxyz";
for(int i=0; i<20; i++) {
cmp.append(str+str+"\n");
}
cmp.setForeground(Color.WHITE);
cmp.setBackground(Color.BLACK);
cmp.setOpaque(true);
JScrollPane scrollPane = new JScrollPane(
cmp, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setComponentZOrder(scrollPane.getVerticalScrollBar(), 0);
scrollPane.setComponentZOrder(scrollPane.getViewport(), 1);
scrollPane.getVerticalScrollBar().setOpaque(false);
scrollPane.setLayout(new ScrollPaneLayout() {
#Override
public void layoutContainer(Container parent) {
JScrollPane scrollPane = (JScrollPane)parent;
Rectangle availR = scrollPane.getBounds();
availR.x = availR.y = 0;
Insets insets = parent.getInsets();
availR.x = insets.left;
availR.y = insets.top;
availR.width -= insets.left + insets.right;
availR.height -= insets.top + insets.bottom;
Rectangle vsbR = new Rectangle();
vsbR.width = 12;
vsbR.height = availR.height;
vsbR.x = availR.x + availR.width - vsbR.width;
vsbR.y = availR.y;
if(viewport != null) {
viewport.setBounds(availR);
}
if(vsb != null) {
vsb.setVisible(true);
vsb.setBounds(vsbR);
}
}
});
scrollPane.getVerticalScrollBar().setUI(new BasicScrollBarUI() {
private final Dimension d = new Dimension();
#Override protected JButton createDecreaseButton(int orientation) {
return new JButton() {
#Override public Dimension getPreferredSize() {
return d;
}
};
}
#Override protected JButton createIncreaseButton(int orientation) {
return new JButton() {
#Override public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle r) {}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
Graphics2D g2 = (Graphics2D)g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
Color color = null;
JScrollBar sb = (JScrollBar)c;
if(!sb.isEnabled() || r.width>r.height) {
return;
}else if(isDragging) {
color = new Color(200,200,100,200);
}else if(isThumbRollover()) {
color = new Color(255,255,100,200);
}else {
color = new Color(220,220,200,200);
}
g2.setPaint(color);
g2.fillRoundRect(r.x,r.y,r.width,r.height,10,10);
g2.setPaint(Color.WHITE);
g2.drawRoundRect(r.x,r.y,r.width,r.height,10,10);
g2.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
scrollbar.repaint();
}
});
return scrollPane;
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new TranslucentScrollBarTest().makeUI());
f.setSize(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}

Here is an improved version I did for a private project. It also supports horizontal scrollbar.
Code:
import javax.swing.*;
import javax.swing.plaf.basic.BasicScrollBarUI;
import java.awt.*;
/**
* This is an implementation of a JScrollPane with a modern UI
*
* #author Philipp Danner
*
*/
public class ModernScrollPane extends JScrollPane {
private static final long serialVersionUID = 8607734981506765935L;
private static final int SCROLL_BAR_ALPHA_ROLLOVER = 100;
private static final int SCROLL_BAR_ALPHA = 50;
private static final int THUMB_SIZE = 8;
private static final int SB_SIZE = 10;
private static final Color THUMB_COLOR = Color.Black;
public ModernScrollPane(Component view) {
this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
}
public ModernScrollPane(int vsbPolicy, int hsbPolicy) {
this(null, vsbPolicy, hsbPolicy);
}
public ModernScrollPane(Component view, int vsbPolicy, int hsbPolicy) {
setBorder(null);
// Set ScrollBar UI
JScrollBar verticalScrollBar = getVerticalScrollBar();
verticalScrollBar.setOpaque(false);
verticalScrollBar.setUI(new ModernScrollBarUI(this));
JScrollBar horizontalScrollBar = getHorizontalScrollBar();
horizontalScrollBar.setOpaque(false);
horizontalScrollBar.setUI(new ModernScrollBarUI(this));
setLayout(new ScrollPaneLayout() {
private static final long serialVersionUID = 5740408979909014146L;
#Override
public void layoutContainer(Container parent) {
Rectangle availR = ((JScrollPane) parent).getBounds();
availR.x = availR.y = 0;
// viewport
Insets insets = parent.getInsets();
availR.x = insets.left;
availR.y = insets.top;
availR.width -= insets.left + insets.right;
availR.height -= insets.top + insets.bottom;
if (viewport != null) {
viewport.setBounds(availR);
}
boolean vsbNeeded = isVerticalScrollBarfNecessary();
boolean hsbNeeded = isHorizontalScrollBarNecessary();
// vertical scroll bar
Rectangle vsbR = new Rectangle();
vsbR.width = SB_SIZE;
vsbR.height = availR.height - (hsbNeeded ? vsbR.width : 0);
vsbR.x = availR.x + availR.width - vsbR.width;
vsbR.y = availR.y;
if (vsb != null) {
vsb.setBounds(vsbR);
}
// horizontal scroll bar
Rectangle hsbR = new Rectangle();
hsbR.height = SB_SIZE;
hsbR.width = availR.width - (vsbNeeded ? hsbR.height : 0);
hsbR.x = availR.x;
hsbR.y = availR.y + availR.height - hsbR.height;
if (hsb != null) {
hsb.setBounds(hsbR);
}
}
});
// Layering
setComponentZOrder(getVerticalScrollBar(), 0);
setComponentZOrder(getHorizontalScrollBar(), 1);
setComponentZOrder(getViewport(), 2);
viewport.setView(view);
}
private boolean isVerticalScrollBarfNecessary() {
Rectangle viewRect = viewport.getViewRect();
Dimension viewSize = viewport.getViewSize();
return viewSize.getHeight() > viewRect.getHeight();
}
private boolean isHorizontalScrollBarNecessary() {
Rectangle viewRect = viewport.getViewRect();
Dimension viewSize = viewport.getViewSize();
return viewSize.getWidth() > viewRect.getWidth();
}
/**
* Class extending the BasicScrollBarUI and overrides all necessary methods
*/
private static class ModernScrollBarUI extends BasicScrollBarUI {
private JScrollPane sp;
public ModernScrollBarUI(ModernScrollPane sp) {
this.sp = sp;
}
#Override
protected JButton createDecreaseButton(int orientation) {
return new InvisibleScrollBarButton();
}
#Override
protected JButton createIncreaseButton(int orientation) {
return new InvisibleScrollBarButton();
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle trackBounds) {
}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds) {
int alpha = isThumbRollover() ? SCROLL_BAR_ALPHA_ROLLOVER : SCROLL_BAR_ALPHA;
int orientation = scrollbar.getOrientation();
int x = thumbBounds.x;
int y = thumbBounds.y;
int width = orientation == JScrollBar.VERTICAL ? THUMB_SIZE : thumbBounds.width;
width = Math.max(width, THUMB_SIZE);
int height = orientation == JScrollBar.VERTICAL ? thumbBounds.height : THUMB_SIZE;
height = Math.max(height, THUMB_SIZE);
Graphics2D graphics2D = (Graphics2D) g.create();
graphics2D.setColor(new Color(THUMB_COLOR.getRed(), THUMB_COLOR.getGreen(), THUMB_COLOR.getBlue(), alpha));
graphics2D.fillRect(x, y, width, height);
graphics2D.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
sp.repaint();
}
/**
* Invisible Buttons, to hide scroll bar buttons
*/
private static class InvisibleScrollBarButton extends JButton {
private static final long serialVersionUID = 1552427919226628689L;
private InvisibleScrollBarButton() {
setOpaque(false);
setFocusable(false);
setFocusPainted(false);
setBorderPainted(false);
setBorder(BorderFactory.createEmptyBorder());
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(400, 400));
JPanel content = new JPanel();
content.setBackground(Color.WHITE);
content.setPreferredSize(new Dimension(500, 500));
content.add(new JLabel("test"));
frame.add(new ModernScrollPane(content));
frame.pack();
frame.setVisible(true);
}
}

Custom scrollbar preview :
Custom scrollbar code :
public class CustomScrollBarUI extends BasicScrollBarUI {
private final Dimension d = new Dimension();
#Override
protected JButton createDecreaseButton(int orientation) {
return new JButton() {
private static final long serialVersionUID = -3592643796245558676L;
#Override
public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected JButton createIncreaseButton(int orientation) {
return new JButton() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle r) {
}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color color = null;
JScrollBar sb = (JScrollBar) c;
if (!sb.isEnabled() || r.width > r.height) {
return;
} else if (isDragging) {
color = Color.DARK_GRAY; // change color
} else if (isThumbRollover()) {
color = Color.LIGHT_GRAY; // change color
} else {
color = Color.GRAY; // change color
}
g2.setPaint(color);
g2.fillRoundRect(r.x, r.y, r.width, r.height, 10, 10);
g2.setPaint(Color.WHITE);
g2.drawRoundRect(r.x, r.y, r.width, r.height, 10, 10);
g2.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
scrollbar.repaint();
}
}
Then use it like this:
YOUR_COMPONENT.getVerticalScrollBar().setUI(new CustomScrollBarUI());

Sadly the proposed solutions will break JTable and won't display the table header, but I found this solution that seems to work.