The following code is working in jdk 1.8 update 45 and in java 1.8 update 31 but NOT in java 1.8 update 45.
The program is a button moving back and forth until the user presses the button and makes it stop and the text is changed to "MOVE". When the button is pressed again, the button starts moving and the text is changed to "STOP".
In java 8 update 45, the button does not start moving but the text changes. Why?
package mainpackage;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class mainPanel implements ActionListener {
JFrame frame1;
JPanel panel1;
JButton button = new JButton("STOP");
boolean buttonPressed = false;
boolean move = true;
// 0 = left & 1 = right
int direction = 1;
int x = 0;
public static void main(String[] args) {
new mainPanel().loadGUI();
}
public void loadGUI() {
frame1 = new JFrame("Moving button");
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setVisible(true);
frame1.setSize(300, 58);
frame1.setResizable(false);
panel1 = new JPanel(); // Xwidth=294, Yheight=272
panel1.setSize(300, 30);
panel1.setLayout(null);
frame1.add(panel1);
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
frame1.setLocation(dim.width/2-frame1.getSize().width/2, dim.height/2-frame1.getSize().height/2);
button.setSize(80, 30); //X, Y
panel1.add(button);
button.addActionListener(this);
while(true) moveButton();
}
public void moveButton() {
while(move == true) {
switch(direction) {
// left
case 0: {
while(x > 0) {
if(move == false) break;
button.setLocation(x, 0);
x--;
panel1.repaint();
try {
Thread.sleep(10);
} catch (InterruptedException ex) {
Logger.getLogger(mainPanel.class.getName()).log(Level.SEVERE, null, ex);
}
}
if(buttonPressed == true) {
direction = 0;
buttonPressed = false;
} else if(buttonPressed == false) {
direction = 1;
buttonPressed = false;
}
}
// right
case 1: {
while(x < panel1.getWidth() - button.getWidth()) {
if(move == false) break;
button.setLocation(x, 0);
x++;
panel1.repaint();
try {
Thread.sleep(10);
} catch (InterruptedException ex) {
Logger.getLogger(mainPanel.class.getName()).log(Level.SEVERE, null, ex);
}
}
if(buttonPressed == true) {
direction = 1;
buttonPressed=false;
} else if(buttonPressed == false) {
direction=0;
buttonPressed=false;
}
}
}
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (move == true){
move=false;
} else if (move == false) {
move=true;
}
buttonPressed = true;
if((button.getText()).equals("STOP")) {
button.setText("MOVE");
} else button.setText("STOP");
}
}
Yours is broken code to begin with since it ignores Swing threading rules, and frankly I'm surprised that it worked in previous versions of Java. You're calling a while (true) loop that will tie up any thread that it is called in. Java 8 is correctly trying to start your Swing GUI on the Swing event thread, something that all Swing programs should do. If you get rid of the while (true) loops that risk being called on the Swing event dispatch thread, and instead use a Swing Timer your code should work. The Timer will run a loop in a background thread, but all code called repeatedly in its ActionListener will be called on the Swing event thread.
For example:
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class MyMainPanel extends JPanel {
private static final int PREF_W = 300;
private static final int PREF_H = 30;
private static final int TIMER_DELAY = 20;
public static final int DELTA_X = 3;
private JButton moveButton = new JButton(new MoveButtonAction("Move"));
private Timer moveTimer = new Timer(TIMER_DELAY, new MoveTimerListener());
private boolean moveRight = true;
public MyMainPanel() {
moveButton.setSize(moveButton.getPreferredSize());
int y = (getPreferredSize().height - moveButton.getPreferredSize().height) / 2;
moveButton.setLocation(0, y);
setLayout(null); // !! lord I hate this
add(moveButton);
moveTimer.start();
}
#Override
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
int prefW = Math.max(superSz.width, PREF_W);
int prefH = Math.max(superSz.height, PREF_H);
return new Dimension(prefW, prefH);
}
private class MoveButtonAction extends AbstractAction {
public MoveButtonAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
moveRight = !moveRight;
}
}
private class MoveTimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (moveRight) {
if (moveButton.getLocation().x + moveButton.getWidth() >= getWidth()) {
moveRight = false;
}
} else {
if (moveButton.getLocation().x <= 0) {
moveRight = true;
}
}
int x = moveButton.getLocation().x + (moveRight ? DELTA_X : -DELTA_X);
int y = moveButton.getLocation().y;
moveButton.setLocation(new Point(x, y));
repaint();
}
}
private static void createAndShowGui() {
MyMainPanel mainPanel = new MyMainPanel();
JFrame frame = new JFrame("GUI Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
You will want to read up on Swing thread safety to see why your program is failing. See Lesson: Concurrency in Swing to see more on this.
Edit: code that stops and starts movement:
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
#SuppressWarnings("serial")
public class MyMainPanel extends JPanel {
private static final String MOVE = "Move";
private static final String STOP = "Stop";
private static final int PREF_W = 300;
private static final int PREF_H = 30;
private static final int TIMER_DELAY = 20;
public static final int DELTA_X = 3;
private MoveButtonAction moveButtonAction = new MoveButtonAction(STOP);
private JButton moveButton = new JButton(moveButtonAction);
private Timer moveTimer = new Timer(TIMER_DELAY, new MoveTimerListener());
private boolean moveRight = true;
public MyMainPanel() {
moveButton.setSize(moveButton.getPreferredSize());
int y = (getPreferredSize().height - moveButton.getPreferredSize().height) / 2;
moveButton.setLocation(0, y);
setLayout(null); // !! lord I hate this
add(moveButton);
moveTimer.start();
}
#Override
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
int prefW = Math.max(superSz.width, PREF_W);
int prefH = Math.max(superSz.height, PREF_H);
return new Dimension(prefW, prefH);
}
private class MoveButtonAction extends AbstractAction {
public MoveButtonAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
if (MOVE.equals(getValue(NAME))) {
moveTimer.start();
putValue(NAME, STOP);
int mnemonic = (int) STOP.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
} else {
moveTimer.stop();
putValue(NAME, MOVE);
int mnemonic = (int) MOVE.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
AbstractButton button = (AbstractButton) e.getSource();
button.setSize(button.getPreferredSize());
repaint();
}
}
private class MoveTimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (moveRight) {
if (moveButton.getLocation().x + moveButton.getWidth() >= getWidth()) {
moveRight = false;
}
} else {
if (moveButton.getLocation().x <= 0) {
moveRight = true;
}
}
int x = moveButton.getLocation().x + (moveRight ? DELTA_X : -DELTA_X);
int y = moveButton.getLocation().y;
moveButton.setLocation(new Point(x, y));
repaint();
}
}
private static void createAndShowGui() {
MyMainPanel mainPanel = new MyMainPanel();
JFrame frame = new JFrame("GUI Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Just added some methods and fixed some lines in your code, you can try it now:
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class mainPanel implements ActionListener {
JFrame frame1;
JPanel panel1;
JButton button = new JButton("START");
boolean buttonPressed = false;
boolean move = false;
Timer timer;
int direction = 1;
int x = 0;
public static void main(String[] args) {
new mainPanel().loadGUI();
}
public void loadGUI() {
frame1 = new JFrame("Moving button");
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setVisible(true);
frame1.setSize(300, 58);
frame1.setResizable(false);
panel1 = new JPanel(); // Xwidth=294, Yheight=272
panel1.setSize(300, 30);
panel1.setLayout(null);
frame1.add(panel1);
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
frame1.setLocation(dim.width / 2 - frame1.getSize().width / 2, dim.height / 2 - frame1.getSize().height / 2);
button.setSize(80, 30); //X, Y
panel1.add(button);
button.addActionListener(this);
moveButton();
}
public void moveButton() {
if (timer == null) {
initTimer();
}
move = !move;
if (move) {
button.setText("STOP");
direction = (direction == 0) ? 1 : 0;
timer.start();
} else {
button.setText("MOVE");
timer.stop();
}
}
public void initTimer() {
timer = new Timer(10, (e) -> {
switch (direction) {
case 0: // right
x++;
if (x >= panel1.getWidth() - button.getWidth()) {
direction = 1;
}
break;
case 1: // left
x--;
if (x <= 0) {
direction = 0;
}
break;
}
button.setLocation(x, 0);
panel1.repaint();
});
}
#Override
public void actionPerformed(ActionEvent e) {
moveButton();
}
}
Related
I have written a sample code using KeyListener in Java,
I have created a JPanel, then set its focusable to true, I have created a KeyListener, requested a focus and then added the KeyListener to my panel. But the methods for the keyListener are never called. It seems although I have requested focus, it does not focus.
Can anyone help?
listener = new KeyLis();
this.setFocusable(true);
this.requestFocus();
this.addKeyListener(listener);
class KeyLis implements KeyListener{
#Override
public void keyPressed(KeyEvent e) {
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT : if(horizontalyInBounds()) currentPos-= 5;
break;
case KeyEvent.VK_RIGHT: if(horizontalyInBounds()) currentPos+= 5;
break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
}
}
If any runnable code should be needed:
import java.awt.Color;
import java.awt.Graphics;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class test extends JFrame {
private AreaOfGame areaOfGame;
public test()
{
super("");
setVisible(true);
this.setBackground(Color.darkGray);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
setLayout(null);
setBounds(200, 10, 400, 700);
areaOfGame = new AreaOfGame();
this.add(areaOfGame);
startGame();
}
public int generateNext()
{
Random r = new Random();
int n = r.nextInt(7);
return n;
}
public void startGame()
{
while(!areaOfGame.GameOver())
{
areaOfGame.startGame(generateNext());
}
}
public static void main(String[] args) {
new MainFrame();
}
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JPanel;
public class AreaOfGame extends JPanel {
private static final int rightside = 370;
private int bottom;
private int top;
private int currentPos;
private int currentver;
private KeyLis listener;
public AreaOfGame()
{
super();
bottom = 650;
top = 50;
setLayout(null);
setBounds(20, 50, 350, 600);
setVisible(true);
this.setBackground(Color.lightGray);
listener = new KeyLis();
this.setFocusable(true);
if(this.requestFocus(true))
System.out.println("true");;
this.addKeyListener(listener);
currentPos = 150;
currentver=0;
}
public void startGame(int n)
{
while(verticallyInBound()){
System.out.println("anything");
}
}
public boolean verticallyInBound()
{
if(currentPos<= bottom -50)
return true;
return false;
}
public boolean GameOver()
{
if(top>= bottom){
System.out.println("game over");
return true;
}
else return false;
}
public boolean horizontalyInBounds()
{
if(currentPos<=rightside && currentPos>= 20)
return true;
else return false;
}
class KeyLis implements KeyListener{
#Override
public void keyPressed(KeyEvent e) {
System.out.println("called");
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT : if(horizontalyInBounds()) currentPos-= 5; break;
case KeyEvent.VK_RIGHT: if(horizontalyInBounds()) currentPos+= 5; break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
System.out.println("called 3");
}
}
}
I'll bet that you're requesting focus before the JPanel has been rendered (before the top level window has either had pack() or setVisible(true) called), and if so, this won't work. Focus request will only be possibly granted after components have been rendered. Have you checked what your call to requestFocus() has returned? It must return true for your call to have any chance for a success. Also it's better to use requestFocusInWindow() rather than requestFocus().
But more importantly, you shouldn't be using KeyListeners for this but rather key bindings, a higher level concept that Swing itself uses to respond to key presses.
Edit
An example of an SSCCE:
import java.awt.Dimension;
import java.awt.event.*;
import javax.swing.*;
public class TestKeyListener extends JPanel {
private KeyLis listener;
public TestKeyListener() {
add(new JButton("Foo")); // something to draw off focus
listener = new KeyLis();
this.setFocusable(true);
this.requestFocus();
this.addKeyListener(listener);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
private class KeyLis extends KeyAdapter {
#Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
System.out.println("VK_LEFT pressed");
break;
case KeyEvent.VK_RIGHT:
System.out.println("VK_RIGHT pressed");
break;
}
}
}
private static void createAndShowGui() {
TestKeyListener mainPanel = new TestKeyListener();
JFrame frame = new JFrame("TestKeyListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Edit 2
And the equivalent SSCCE using Key Bindings:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class TestKeyBindings extends JPanel {
public TestKeyBindings() {
add(new JButton("Foo")); // something to draw off focus
setKeyBindings();
}
private void setKeyBindings() {
ActionMap actionMap = getActionMap();
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition );
String vkLeft = "VK_LEFT";
String vkRight = "VK_RIGHT";
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), vkLeft);
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), vkRight);
actionMap.put(vkLeft, new KeyAction(vkLeft));
actionMap.put(vkRight, new KeyAction(vkRight));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
private class KeyAction extends AbstractAction {
public KeyAction(String actionCommand) {
putValue(ACTION_COMMAND_KEY, actionCommand);
}
#Override
public void actionPerformed(ActionEvent actionEvt) {
System.out.println(actionEvt.getActionCommand() + " pressed");
}
}
private static void createAndShowGui() {
TestKeyBindings mainPanel = new TestKeyBindings();
JFrame frame = new JFrame("TestKeyListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Edit 3
Regarding your recent SSCCE, your while (true) loops are blocking your Swing event thread and may prevent user interaction or painting from happening. Better to use a Swing Timer rather than while (true). For example:
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class BbbTest extends JFrame {
private AreaOfGame areaOfGame;
public BbbTest() {
super("");
// setVisible(true);
this.setBackground(Color.darkGray);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
setLayout(null);
setBounds(200, 10, 400, 700);
areaOfGame = new AreaOfGame();
this.add(areaOfGame);
setVisible(true);
startGame();
}
public int generateNext() {
Random r = new Random();
int n = r.nextInt(7);
return n;
}
public void startGame() {
// while (!areaOfGame.GameOver()) {
// areaOfGame.startGame(generateNext());
// }
areaOfGame.startGame(generateNext());
}
public static void main(String[] args) {
new BbbTest();
}
class AreaOfGame extends JPanel {
private static final int rightside = 370;
private int bottom;
private int top;
private int currentPos;
private int currentver;
private KeyLis listener;
public AreaOfGame() {
super();
bottom = 650;
top = 50;
setLayout(null);
setBounds(20, 50, 350, 600);
setVisible(true);
this.setBackground(Color.lightGray);
listener = new KeyLis();
this.setFocusable(true);
if (this.requestFocus(true))
System.out.println("true");
;
this.addKeyListener(listener);
currentPos = 150;
currentver = 0;
}
public void startGame(int n) {
// while (verticallyInBound()) {
// System.out.println("anything");
// }
int timeDelay = 50; // msecs delay
new Timer(timeDelay , new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
System.out.println("anything");
}
}).start();
}
public boolean verticallyInBound() {
if (currentPos <= bottom - 50)
return true;
return false;
}
public boolean GameOver() {
if (top >= bottom) {
System.out.println("game over");
return true;
}
else
return false;
}
public boolean horizontalyInBounds() {
if (currentPos <= rightside && currentPos >= 20)
return true;
else
return false;
}
class KeyLis implements KeyListener {
#Override
public void keyPressed(KeyEvent e) {
System.out.println("called");
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
if (horizontalyInBounds())
currentPos -= 5;
break;
case KeyEvent.VK_RIGHT:
if (horizontalyInBounds())
currentPos += 5;
break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
System.out.println("called 3");
}
}
}
}
It's possible to use the "TAB" button to switch between the buttons and the key listener.
I have a program with one button that after I press it, the key listener does not work.
I realized that if you press the "TAB" button, the "Attention" or "focus" of the program returns to the key listener.
maybe this will help: http://docstore.mik.ua/orelly/java-ent/jfc/ch03_08.htm
I have written a sample code using KeyListener in Java,
I have created a JPanel, then set its focusable to true, I have created a KeyListener, requested a focus and then added the KeyListener to my panel. But the methods for the keyListener are never called. It seems although I have requested focus, it does not focus.
Can anyone help?
listener = new KeyLis();
this.setFocusable(true);
this.requestFocus();
this.addKeyListener(listener);
class KeyLis implements KeyListener{
#Override
public void keyPressed(KeyEvent e) {
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT : if(horizontalyInBounds()) currentPos-= 5;
break;
case KeyEvent.VK_RIGHT: if(horizontalyInBounds()) currentPos+= 5;
break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
}
}
If any runnable code should be needed:
import java.awt.Color;
import java.awt.Graphics;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class test extends JFrame {
private AreaOfGame areaOfGame;
public test()
{
super("");
setVisible(true);
this.setBackground(Color.darkGray);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
setLayout(null);
setBounds(200, 10, 400, 700);
areaOfGame = new AreaOfGame();
this.add(areaOfGame);
startGame();
}
public int generateNext()
{
Random r = new Random();
int n = r.nextInt(7);
return n;
}
public void startGame()
{
while(!areaOfGame.GameOver())
{
areaOfGame.startGame(generateNext());
}
}
public static void main(String[] args) {
new MainFrame();
}
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JPanel;
public class AreaOfGame extends JPanel {
private static final int rightside = 370;
private int bottom;
private int top;
private int currentPos;
private int currentver;
private KeyLis listener;
public AreaOfGame()
{
super();
bottom = 650;
top = 50;
setLayout(null);
setBounds(20, 50, 350, 600);
setVisible(true);
this.setBackground(Color.lightGray);
listener = new KeyLis();
this.setFocusable(true);
if(this.requestFocus(true))
System.out.println("true");;
this.addKeyListener(listener);
currentPos = 150;
currentver=0;
}
public void startGame(int n)
{
while(verticallyInBound()){
System.out.println("anything");
}
}
public boolean verticallyInBound()
{
if(currentPos<= bottom -50)
return true;
return false;
}
public boolean GameOver()
{
if(top>= bottom){
System.out.println("game over");
return true;
}
else return false;
}
public boolean horizontalyInBounds()
{
if(currentPos<=rightside && currentPos>= 20)
return true;
else return false;
}
class KeyLis implements KeyListener{
#Override
public void keyPressed(KeyEvent e) {
System.out.println("called");
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT : if(horizontalyInBounds()) currentPos-= 5; break;
case KeyEvent.VK_RIGHT: if(horizontalyInBounds()) currentPos+= 5; break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
System.out.println("called 3");
}
}
}
I'll bet that you're requesting focus before the JPanel has been rendered (before the top level window has either had pack() or setVisible(true) called), and if so, this won't work. Focus request will only be possibly granted after components have been rendered. Have you checked what your call to requestFocus() has returned? It must return true for your call to have any chance for a success. Also it's better to use requestFocusInWindow() rather than requestFocus().
But more importantly, you shouldn't be using KeyListeners for this but rather key bindings, a higher level concept that Swing itself uses to respond to key presses.
Edit
An example of an SSCCE:
import java.awt.Dimension;
import java.awt.event.*;
import javax.swing.*;
public class TestKeyListener extends JPanel {
private KeyLis listener;
public TestKeyListener() {
add(new JButton("Foo")); // something to draw off focus
listener = new KeyLis();
this.setFocusable(true);
this.requestFocus();
this.addKeyListener(listener);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
private class KeyLis extends KeyAdapter {
#Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
System.out.println("VK_LEFT pressed");
break;
case KeyEvent.VK_RIGHT:
System.out.println("VK_RIGHT pressed");
break;
}
}
}
private static void createAndShowGui() {
TestKeyListener mainPanel = new TestKeyListener();
JFrame frame = new JFrame("TestKeyListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Edit 2
And the equivalent SSCCE using Key Bindings:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class TestKeyBindings extends JPanel {
public TestKeyBindings() {
add(new JButton("Foo")); // something to draw off focus
setKeyBindings();
}
private void setKeyBindings() {
ActionMap actionMap = getActionMap();
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition );
String vkLeft = "VK_LEFT";
String vkRight = "VK_RIGHT";
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), vkLeft);
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), vkRight);
actionMap.put(vkLeft, new KeyAction(vkLeft));
actionMap.put(vkRight, new KeyAction(vkRight));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
private class KeyAction extends AbstractAction {
public KeyAction(String actionCommand) {
putValue(ACTION_COMMAND_KEY, actionCommand);
}
#Override
public void actionPerformed(ActionEvent actionEvt) {
System.out.println(actionEvt.getActionCommand() + " pressed");
}
}
private static void createAndShowGui() {
TestKeyBindings mainPanel = new TestKeyBindings();
JFrame frame = new JFrame("TestKeyListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Edit 3
Regarding your recent SSCCE, your while (true) loops are blocking your Swing event thread and may prevent user interaction or painting from happening. Better to use a Swing Timer rather than while (true). For example:
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class BbbTest extends JFrame {
private AreaOfGame areaOfGame;
public BbbTest() {
super("");
// setVisible(true);
this.setBackground(Color.darkGray);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
setLayout(null);
setBounds(200, 10, 400, 700);
areaOfGame = new AreaOfGame();
this.add(areaOfGame);
setVisible(true);
startGame();
}
public int generateNext() {
Random r = new Random();
int n = r.nextInt(7);
return n;
}
public void startGame() {
// while (!areaOfGame.GameOver()) {
// areaOfGame.startGame(generateNext());
// }
areaOfGame.startGame(generateNext());
}
public static void main(String[] args) {
new BbbTest();
}
class AreaOfGame extends JPanel {
private static final int rightside = 370;
private int bottom;
private int top;
private int currentPos;
private int currentver;
private KeyLis listener;
public AreaOfGame() {
super();
bottom = 650;
top = 50;
setLayout(null);
setBounds(20, 50, 350, 600);
setVisible(true);
this.setBackground(Color.lightGray);
listener = new KeyLis();
this.setFocusable(true);
if (this.requestFocus(true))
System.out.println("true");
;
this.addKeyListener(listener);
currentPos = 150;
currentver = 0;
}
public void startGame(int n) {
// while (verticallyInBound()) {
// System.out.println("anything");
// }
int timeDelay = 50; // msecs delay
new Timer(timeDelay , new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
System.out.println("anything");
}
}).start();
}
public boolean verticallyInBound() {
if (currentPos <= bottom - 50)
return true;
return false;
}
public boolean GameOver() {
if (top >= bottom) {
System.out.println("game over");
return true;
}
else
return false;
}
public boolean horizontalyInBounds() {
if (currentPos <= rightside && currentPos >= 20)
return true;
else
return false;
}
class KeyLis implements KeyListener {
#Override
public void keyPressed(KeyEvent e) {
System.out.println("called");
currentver += 5;
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
if (horizontalyInBounds())
currentPos -= 5;
break;
case KeyEvent.VK_RIGHT:
if (horizontalyInBounds())
currentPos += 5;
break;
}
repaint();
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e) {
System.out.println("called 3");
}
}
}
}
It's possible to use the "TAB" button to switch between the buttons and the key listener.
I have a program with one button that after I press it, the key listener does not work.
I realized that if you press the "TAB" button, the "Attention" or "focus" of the program returns to the key listener.
maybe this will help: http://docstore.mik.ua/orelly/java-ent/jfc/ch03_08.htm
Am trying to modify a java code that implements Analog Clock using BufferedImage. I want the face of the clock to be changed dynamically when a user clicks on a button that scrolls through an array preloaded with the locations of images. So far my attempts have failed. I have two classes; The first Class creates and displays the Analog, and the second class attempts to change the face of the Analog clock using a mutator (setAnalogClockFace()) and an accessor (getAnalogClockFace()). The following is the code for the first Class as found on here, with minor modifications:
package panels;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.util.*;
public class Clock extends JPanel{
/**
*
*/
private static final long serialVersionUID = 1L;
private int hours = 0;
private int minutes = 0;
private int seconds = 0;
private int millis = 0;
private static final int spacing = 10;
private static final float threePi = (float)(3.0 * Math.PI);
private static final float radPerSecMin = (float)(Math.PI/30.0);
private int size; //height and width of clockface
private int centerX;//X coord of middle of clock
private int centerY;//Y coord of middle of clock
private BufferedImage clockImage;
private BufferedImage imageToUse;
private javax.swing.Timer t;
public Clock(){
this.setPreferredSize(new Dimension(203,203));
this.setBackground(getBackground());
this.setForeground(Color.darkGray);
t = new javax.swing.Timer(1000, new ActionListener(){
public void actionPerformed(ActionEvent ae){
update();
}
});
}
public void update(){
this.repaint();
}
public void start(){
t.start();
}
public void stop(){
t.stop();
}
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int w = getWidth();
int h = getHeight();
size = ((w < h) ? w : h) - 2 * spacing;
centerX = size/2 + spacing;
centerY = size/2 + spacing;
setClockFace(new AnalogClockTimer().getAnalogClockFace());
clockImage = getClockFace();
if (clockImage == null | clockImage.getWidth() != w | clockImage.getHeight() != h){
clockImage = (BufferedImage)(this.createImage(w,h));
Graphics2D gc = clockImage.createGraphics();
gc.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
drawClockFace(gc);
}
Calendar now = Calendar.getInstance();
hours = now.get(Calendar.HOUR);
minutes = now.get(Calendar.MINUTE);
seconds = now.get(Calendar.SECOND);
millis = now.get(Calendar.MILLISECOND);
g2d.drawImage(clockImage, null, 0, 0);
drawClockHands(g);
}
private void drawClockHands(Graphics g){
int secondRadius = size/2;
int minuteRadius = secondRadius * 3/4;
int hourRadius = secondRadius/2;
float fseconds = seconds + (float)millis/1000;
float secondAngle = threePi - (radPerSecMin * fseconds);
drawRadius(g, centerX, centerY, secondAngle, 0, secondRadius);
float fminutes = (float)(minutes + fseconds/60.0);
float minuteAngle = threePi - (radPerSecMin * fminutes);
drawRadius(g, centerX, centerY, minuteAngle, 0 , minuteRadius);
float fhours = (float)(hours + fminutes/60.0);
float hourAngle = threePi - (5 * radPerSecMin * fhours);
drawRadius(g, centerX, centerY, hourAngle, 0 ,hourRadius);
}
private void drawClockFace(Graphics g){
//g.setColor(Color.lightGray);
g.fillOval(spacing, spacing, size, size);
//g.setColor(new Color(168,168,168));
g.drawOval(spacing, spacing, size, size);
for(int sec = 0; sec < 60; sec++){
int tickStart;
if(sec%5 == 0){
tickStart = size/2-10;
}else{
tickStart = size/2-5;
}
drawRadius(g, centerX, centerY, radPerSecMin * sec, tickStart, size/2);
}
}
private void drawRadius(Graphics g, int x, int y, double angle,
int minRadius, int maxRadius){
float sine = (float)Math.sin(angle);
float cosine = (float)Math.cos(angle);
int dxmin = (int)(minRadius * sine);
int dymin = (int)(minRadius * cosine);
int dxmax = (int)(maxRadius * sine);
int dymax = (int)(maxRadius * cosine);
g.drawLine(x+dxmin, y+dymin, x+dxmax,y+dymax);
}
public void setClockFace(BufferedImage img){
if(img != null){
imageToUse = img;
}else{
try{
imageToUse =
ImageIO.read(getClass().getClassLoader().getResource("http://imgur.com/T8x0I29"));
}catch(IOException io){
io.printStackTrace();
}
}
}
public BufferedImage getClockFace(){
return imageToUse;
}
}
The second Class that attempts to set the Clock face is:
package panels;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.SwingConstants;
import javax.swing.WindowConstants;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import panels.Clock;
public class AnalogClockTimer extends javax.swing.JPanel implements ActionListener,
MouseListener {
private Clock clock;
/**
*
*/
private static final long serialVersionUID = 1L;
private JButton prevBtn;
private JTextField clockFaceCount;
private JButton nextBtn;
private JPanel buttonedPanel,leftPanel,rightPanel;
private BufferedImage image;
String[] clockFace;
int arrayPointer = 1;
/**
* Auto-generated main method to display this
* JPanel inside a new JFrame.
*/
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new AnalogClockTimer());
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public AnalogClockTimer() {
super();
initGUI();
}
private void initGUI() {
try {
BorderLayout thisLayout = new BorderLayout();
this.setLayout(thisLayout);
this.setPreferredSize(new java.awt.Dimension(283, 233));
this.setBackground(getBackground());
{
clock = new Clock();
add(clock,BorderLayout.CENTER);
clock.start();
clock.setSize(203, 203);
}
{
buttonedPanel = new JPanel();
FlowLayout buttonedPanelLayout = new FlowLayout();
buttonedPanel.setLayout(buttonedPanelLayout);
this.add(buttonedPanel, BorderLayout.SOUTH);
buttonedPanel.setPreferredSize(new java.awt.Dimension(283, 30));
{
prevBtn = new JButton(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_rest.png")));
prevBtn.setPreferredSize(new java.awt.Dimension(20, 19));
prevBtn.setBackground(getBackground());
prevBtn.setBorderPainted(false);
prevBtn.setEnabled(false);
prevBtn.addMouseListener(this);
prevBtn.addActionListener(this);
buttonedPanel.add(prevBtn);
}
{
nextBtn = new JButton(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_rest.png")));
nextBtn.setPreferredSize(new java.awt.Dimension(20, 19));
nextBtn.setBackground(getBackground());
nextBtn.setBorderPainted(false);
nextBtn.addMouseListener(this);
nextBtn.addActionListener(this);
}
{
clockFaceCount = new JTextField();
clockFaceCount.setPreferredSize(new java.awt.Dimension(50, 19));
clockFaceCount.setBackground(getBackground());
clockFaceCount.setBorder(null);
clockFaceCount.setHorizontalAlignment(SwingConstants.CENTER);
clockFaceCount.setEditable(false);
buttonedPanel.add(clockFaceCount);
buttonedPanel.add(nextBtn);
}
{
clockFace = new String[]{"http://imgur.com/079QSdJ","http://imgur.com/vQ7tZjI",
"http://imgur.com/T8x0I29"};
for(int i = 1; i <= clockFace.length; i++){
if(i == 1){
nextBtn.setEnabled(true);
prevBtn.setEnabled(false);
}
clockFaceCount.setText(arrayPointer+" of "+clockFace.length);
}
}
{
leftPanel = new JPanel();
leftPanel.setPreferredSize(new Dimension(40, getHeight()));
add(leftPanel,BorderLayout.WEST);
}
{
rightPanel = new JPanel();
rightPanel.setPreferredSize(new Dimension(40,getHeight()));
add(rightPanel,BorderLayout.EAST);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void mouseClicked(MouseEvent me) {
if(me.getSource() == prevBtn)
prevBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_pressed.png")));
else
nextBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_pressed.png")));
}
#Override
public void mouseEntered(MouseEvent me) {
if(me.getSource()==prevBtn)
prevBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_hover.png")));
else
nextBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_hover.png")));
}
#Override
public void mouseExited(MouseEvent me) {
if(me.getSource() == prevBtn)
prevBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_rest.png")));
else
nextBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_rest.png")));
}
#Override
public void mousePressed(MouseEvent me) {
if(me.getSource() == prevBtn){
prevBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_pressed.png")));
}else{
nextBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_pressed.png")));
}
}
#Override
public void mouseReleased(MouseEvent me) {
if(me.getSource() == prevBtn)
prevBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_left_hover.png")));
else
nextBtn.setIcon(new ImageIcon(getClass().getClassLoader().getResource("icons/settings_right_hover.png")));
}
#Override
public void actionPerformed(ActionEvent ae) {
if(ae.getSource() == nextBtn){
{
if(arrayPointer < clockFace.length){
++arrayPointer;
prevBtn.setEnabled(true);
if(arrayPointer == clockFace.length)
nextBtn.setEnabled(false);
}
clockFaceCount.setText(arrayPointer + " of " + clockFace.length);
setAnalogClockFace(arrayPointer);
}
}else if(ae.getSource() == prevBtn){
{
if(arrayPointer > 1){
--arrayPointer;
nextBtn.setEnabled(true);
if(arrayPointer == 1){
clockFaceCount.setText(arrayPointer+" of "+clockFace.length);
prevBtn.setEnabled(false);
}
}
clockFaceCount.setText(arrayPointer + " of "+clockFace.length);
setAnalogClockFace(arrayPointer);
}
}
}
private void setAnalogClockFace(int pointerPosition) {
try{
image = ImageIO.read(getClass().getClassLoader().getResource(clockFace[pointerPosition]));
}catch(IOException io){
io.printStackTrace();
}
}
public BufferedImage getAnalogClockFace(){
return image;
}
}
I've been working on this for days, can someone please help me understand what am not doing right? Any help would be greatly appreciated.
Here is an MCVE using a JLabel to achieve the same result:
package panels;
import java.awt.Dimension;
import javax.swing.ImageIcon;
import javax.swing.SwingConstants;
import javax.swing.WindowConstants;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.event.*;
import java.awt.BorderLayout;
#SuppressWarnings({"serial"})
public class ClockPanel extends javax.swing.JPanel implements ActionListener {
private JLabel clockImageLabel;
private JPanel buttonsPanel;
private JButton next,prev;
private JTextField displayCount;
String[] imageFaces;
int pointer = 1;
/**
* Auto-generated main method to display this
* JPanel inside a new JFrame.
*/
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new ClockPanel());
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public ClockPanel() {
super();
initGUI();
}
private void initGUI() {
try {
setPreferredSize(new Dimension(203, 237));
BorderLayout panelLayout = new BorderLayout();
setLayout(panelLayout);
{
clockImageLabel = new JLabel();
clockImageLabel.setPreferredSize(new Dimension(203,203));
clockImageLabel.setHorizontalAlignment(SwingConstants.CENTER);
clockImageLabel.setVerticalAlignment(SwingConstants.CENTER);
add(clockImageLabel,BorderLayout.NORTH);
}
{
buttonsPanel = new JPanel();
{
next = new JButton(">");
next.addActionListener(this);
}
{
prev = new JButton("<");
prev.addActionListener(this);
displayCount = new JTextField();
displayCount.setBorder(null);
displayCount.setEditable(false);
displayCount.setBackground(getBackground());
displayCount.setHorizontalAlignment(SwingConstants.CENTER);
buttonsPanel.add(prev);
buttonsPanel.add(displayCount);
displayCount.setPreferredSize(new java.awt.Dimension(45, 23));
buttonsPanel.add(next);
add(buttonsPanel,BorderLayout.SOUTH);
}
{
imageFaces = new String[]{"http://imgur.com/T8x0I29",
"http://imgur.com/079QSdJ","http://imgur.com/vQ7tZjI"
};
for(int i = 1; i < imageFaces.length; i++){
if(i == 1){
next.setEnabled(true);
prev.setEnabled(false);
}
displayCount.setText(pointer+" of "+imageFaces.length);
setLabelImage(pointer);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void setLabelImage(int pointerPosition){
clockImageLabel.setIcon(new ImageIcon(getClass().getClassLoader().getResource(imageFaces[pointerPosition])));
this.repaint();
}
#Override
public void actionPerformed(ActionEvent ae) {
if(ae.getSource() == next){
if(pointer < imageFaces.length){
++pointer;
prev.setEnabled(true);
if(pointer == imageFaces.length)next.setEnabled(false);
displayCount.setText(pointer+" of "+imageFaces.length);
setLabelImage(pointer);
}
}else if(ae.getSource() == prev){
if(pointer > 1){
--pointer;
next.setEnabled(true);
if(pointer == 1)prev.setEnabled(false);
displayCount.setText(pointer+" of "+imageFaces.length);
setLabelImage(pointer);
}
}
}
}
Here are 1/2 Images for the code:
HandlessAnalogClock 1
HandlessAnalogClock 2
HandlessAnalogClock 3
This MCVE will successfully flip between two of the three images, but still has problems with ArrayIndexOutOfBoundsException.
That last part is 'Batteries Not Included' (left as an exercise for the user to correct).
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.ImageIO;
import java.net.URL;
#SuppressWarnings({"serial"})
public class ClockPanel extends JPanel implements ActionListener {
private JLabel clockImageLabel;
private JPanel buttonsPanel;
private JButton next, prev;
private JTextField displayCount;
BufferedImage[] images;
int pointer = 1;
/**
* Auto-generated main method to display this JPanel inside a new JFrame.
*/
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new ClockPanel());
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.pack();
frame.setVisible(true);
}
public ClockPanel() {
super();
initGUI();
}
private void initGUI() {
try {
setPreferredSize(new Dimension(203, 237));
BorderLayout panelLayout = new BorderLayout();
setLayout(panelLayout);
clockImageLabel = new JLabel();
clockImageLabel.setPreferredSize(new Dimension(203, 203));
clockImageLabel.setHorizontalAlignment(SwingConstants.CENTER);
clockImageLabel.setVerticalAlignment(SwingConstants.CENTER);
add(clockImageLabel, BorderLayout.NORTH);
buttonsPanel = new JPanel();
next = new JButton(">");
next.addActionListener(this);
prev = new JButton("<");
prev.addActionListener(this);
displayCount = new JTextField();
displayCount.setBorder(null);
displayCount.setEditable(false);
displayCount.setBackground(getBackground());
displayCount.setHorizontalAlignment(SwingConstants.CENTER);
buttonsPanel.add(prev);
buttonsPanel.add(displayCount);
displayCount.setPreferredSize(new java.awt.Dimension(45, 23));
buttonsPanel.add(next);
add(buttonsPanel, BorderLayout.SOUTH);
String[] imageFaces = new String[]{
"http://i.imgur.com/T8x0I29.png",
"http://i.imgur.com/079QSdJ.png",
"http://i.imgur.com/vQ7tZjI.png"
};
images = new BufferedImage[imageFaces.length];
for (int ii=0; ii<imageFaces.length; ii++) {
System.out.println("loading image: " + ii);
images[ii] = ImageIO.read(new URL(imageFaces[ii]));
System.out.println("loaded image: " + images[ii]);
}
setLabelImage(0);
} catch (Exception e) {
e.printStackTrace();
}
}
private void setLabelImage(int pointerPosition) {
System.out.println("setLabelImage: " + pointerPosition);
clockImageLabel.setIcon(new ImageIcon(images[pointerPosition]));
this.repaint();
}
#Override
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == next) {
if (pointer < images.length) {
++pointer;
prev.setEnabled(true);
if (pointer == images.length) {
next.setEnabled(false);
}
displayCount.setText(pointer + " of " + images.length);
setLabelImage(pointer);
}
} else if (ae.getSource() == prev) {
if (pointer > 1) {
--pointer;
next.setEnabled(true);
if (pointer == 1) {
prev.setEnabled(false);
}
displayCount.setText(pointer + " of " + images.length);
setLabelImage(pointer);
}
}
}
}
Expanding on #Andrew's example, consider arranging for the index of the current image to wrap-around, as shown in the example cited here.
private int pointer = 0;
...
private void initGUI() {
...
setLabelImage(pointer);
...
}
private void setLabelImage(int pointerPosition) {
System.out.println("setLabelImage: " + pointerPosition);
clockImageLabel.setIcon(new ImageIcon(images[pointerPosition]));
displayCount.setText((pointerPosition + 1) + " of " + images.length);
this.repaint();
}
#Override
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == next) {
pointer++;
if (pointer >= images.length) {
pointer = 0;
}
} else if (ae.getSource() == prev) {
pointer--;
if (pointer < 0) {
pointer = images.length - 1;
}
}
setLabelImage(pointer);
}
As an exercise, try to factor out the repeated instantiation of ImageIcon in setLabelImage() by creating a List<ImageIcon> in initGUI().
I have a menu that has a variety of buttons on display, I'm able to make the buttons call their respective JPanels when clicked. The thing is I would like to make the Jpanel slide in when its called instead of instantaneously popping in. I tried using tween engine and as Java beginner, I find it really overwhelming, so I decided to use timed animation. I was able to make the Jpanel on top to slide to one side but for some reason the next panel doesn't want to display, im really tired, can someone help please! There code is below:
public class Listener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
new Timer(0, new ActionListener() {
public void actionPerformed(ActionEvent e) {
mainpane.setLocation(mainpane.getX() - 10, 0);
if (mainpane.getX() + mainpane.getWidth() == 0)
{
((Timer) e.getSource()).stop();
System.out.println("Timer stopped");
}
}
}).start();
}
}
Sliding panels can be tricky. Here is some starter code. Modify to fit
your needs. Add error checking and exception handling as necessary.
This example uses JButtons and a JTree as content but you can use just about any type of content.
Usage:
static public void main(final String[] args) throws Exception {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
final JFrame jFrame = new JFrame() {
{
final PanelSlider42<JFrame> slider = new PanelSlider42<JFrame>(this);
final JPanel jPanel = slider.getBasePanel();
slider.addComponent(new JButton("1"));
slider.addComponent(new JButton("22"));
slider.addComponent(new JButton("333"));
slider.addComponent(new JButton("4444"));
getContentPane().add(jPanel);
setSize(300, 300);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setVisible(true);
}
};
}
});
}
The impl is lengthy ...
package com.java42.example.code;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Cursor;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseMotionAdapter;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JWindow;
import javax.swing.SwingUtilities;
public class PanelSlider42<ParentType extends Container> {
private static final int RIGHT = 0x01;
private static final int LEFT = 0x02;
private static final int TOP = 0x03;
private static final int BOTTOM = 0x04;
private final JPanel basePanel = new JPanel();
private final ParentType parent;
private final Object lock = new Object();
private final ArrayList<Component> jPanels = new ArrayList<Component>();
private final boolean useSlideButton = true;
private boolean isSlideInProgress = false;
private final JPanel glassPane;
{
glassPane = new JPanel();
glassPane.setOpaque(false);
glassPane.addMouseListener(new MouseAdapter() {
});
glassPane.addMouseMotionListener(new MouseMotionAdapter() {
});
glassPane.addKeyListener(new KeyAdapter() {
});
}
public PanelSlider42(final ParentType parent) {
if (parent == null) {
throw new RuntimeException("ProgramCheck: Parent can not be null.");
}
if ((parent instanceof JFrame) || (parent instanceof JDialog) || (parent instanceof JWindow) || (parent instanceof JPanel)) {
}
else {
throw new RuntimeException("ProgramCheck: Parent type not supported. " + parent.getClass().getSimpleName());
}
this.parent = parent;
attach();
basePanel.setSize(parent.getSize());
basePanel.setLayout(new BorderLayout());
if (useSlideButton) {
final JPanel statusPanel = new JPanel();
basePanel.add(statusPanel, BorderLayout.SOUTH);
statusPanel.add(new JButton("Slide Left") {
private static final long serialVersionUID = 9204819004142223529L;
{
setMargin(new Insets(0, 0, 0, 0));
}
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
slideLeft();
}
});
}
});
statusPanel.add(new JButton("Slide Right") {
{
setMargin(new Insets(0, 0, 0, 0));
}
private static final long serialVersionUID = 9204819004142223529L;
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
slideRight();
}
});
}
});
statusPanel.add(new JButton("Slide Up") {
{
setMargin(new Insets(0, 0, 0, 0));
}
private static final long serialVersionUID = 9204819004142223529L;
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
slideTop();
}
});
}
});
statusPanel.add(new JButton("Slide Down") {
{
setMargin(new Insets(0, 0, 0, 0));
}
private static final long serialVersionUID = 9204819004142223529L;
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
slideBottom();
}
});
}
});
}
}
public JPanel getBasePanel() {
return basePanel;
}
private void attach() {
final ParentType w = this.parent;
if (w instanceof JFrame) {
final JFrame j = (JFrame) w;
if (j.getContentPane().getComponents().length > 0) {
throw new RuntimeException("ProgramCheck: Parent already contains content.");
}
j.getContentPane().add(basePanel);
}
if (w instanceof JDialog) {
final JDialog j = (JDialog) w;
if (j.getContentPane().getComponents().length > 0) {
throw new RuntimeException("ProgramCheck: Parent already contains content.");
}
j.getContentPane().add(basePanel);
}
if (w instanceof JWindow) {
final JWindow j = (JWindow) w;
if (j.getContentPane().getComponents().length > 0) {
throw new RuntimeException("ProgramCheck: Parent already contains content.");
}
j.getContentPane().add(basePanel);
}
if (w instanceof JPanel) {
final JPanel j = (JPanel) w;
if (j.getComponents().length > 0) {
throw new RuntimeException("ProgramCheck: Parent already contains content.");
}
j.add(basePanel);
}
}
public void addComponent(final Component component) {
if (jPanels.contains(component)) {
}
else {
jPanels.add(component);
if (jPanels.size() == 1) {
basePanel.add(component);
}
component.setSize(basePanel.getSize());
component.setLocation(0, 0);
}
}
public void removeComponent(final Component component) {
if (jPanels.contains(component)) {
jPanels.remove(component);
}
}
public void slideLeft() {
slide(LEFT);
}
public void slideRight() {
slide(RIGHT);
}
public void slideTop() {
slide(TOP);
}
public void slideBottom() {
slide(BOTTOM);
}
private void enableUserInput(final ParentType w) {
if (w instanceof JFrame) {
((JFrame) w).getGlassPane().setVisible(false);
}
if (w instanceof JDialog) {
((JDialog) w).getGlassPane().setVisible(false);
}
if (w instanceof JWindow) {
((JWindow) w).getGlassPane().setVisible(false);
}
}
private void disableUserInput(final ParentType w) {
if (w instanceof JFrame) {
((JFrame) w).setGlassPane(glassPane);
}
if (w instanceof JDialog) {
((JDialog) w).setGlassPane(glassPane);
}
if (w instanceof JWindow) {
((JWindow) w).setGlassPane(glassPane);
}
glassPane.setVisible(true);
}
private void enableTransparentOverylay() {
if (parent instanceof JFrame) {
((JFrame) parent).getContentPane().setBackground(jPanels.get(0).getBackground());
parent.remove(basePanel);
parent.validate();
}
if (parent instanceof JDialog) {
((JDialog) parent).getContentPane().setBackground(jPanels.get(0).getBackground());
parent.remove(basePanel);
parent.validate();
}
if (parent instanceof JWindow) {
((JWindow) parent).getContentPane().setBackground(jPanels.get(0).getBackground());
parent.remove(basePanel);
parent.validate();
}
}
private void slide(final int slideType) {
if (!isSlideInProgress) {
isSlideInProgress = true;
final Thread t0 = new Thread(new Runnable() {
#Override
public void run() {
parent.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
disableUserInput(parent);
slide(true, slideType);
enableUserInput(parent);
parent.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
isSlideInProgress = false;
}
});
t0.setDaemon(true);
t0.start();
}
else {
Toolkit.getDefaultToolkit().beep();
}
}
private void slide(final boolean useLoop, final int slideType) {
if (jPanels.size() < 2) {
System.err.println("Not enough panels");
return;
}
synchronized (lock) {
Component componentOld = null;
Component componentNew = null;
if ((slideType == LEFT) || (slideType == TOP)) {
componentNew = jPanels.remove(jPanels.size() - 1);
componentOld = jPanels.get(0);
jPanels.add(0, componentNew);
}
if ((slideType == RIGHT) || (slideType == BOTTOM)) {
componentOld = jPanels.remove(0);
jPanels.add(componentOld);
componentNew = jPanels.get(0);
}
final int w = componentOld.getWidth();
final int h = componentOld.getHeight();
final Point p1 = componentOld.getLocation();
final Point p2 = new Point(0, 0);
if (slideType == LEFT) {
p2.x += w;
}
if (slideType == RIGHT) {
p2.x -= w;
}
if (slideType == TOP) {
p2.y += h;
}
if (slideType == BOTTOM) {
p2.y -= h;
}
componentNew.setLocation(p2);
int step = 0;
if ((slideType == LEFT) || (slideType == RIGHT)) {
step = (int) (((float) parent.getWidth() / (float) Toolkit.getDefaultToolkit().getScreenSize().width) * 40.f);
}
else {
step = (int) (((float) parent.getHeight() / (float) Toolkit.getDefaultToolkit().getScreenSize().height) * 20.f);
}
step = step < 5 ? 5 : step;
basePanel.add(componentNew);
basePanel.revalidate();
if (useLoop) {
final int max = (slideType == LEFT) || (slideType == RIGHT) ? w : h;
final long t0 = System.currentTimeMillis();
for (int i = 0; i != (max / step); i++) {
switch (slideType) {
case LEFT: {
p1.x -= step;
componentOld.setLocation(p1);
p2.x -= step;
componentNew.setLocation(p2);
break;
}
case RIGHT: {
p1.x += step;
componentOld.setLocation(p1);
p2.x += step;
componentNew.setLocation(p2);
break;
}
case TOP: {
p1.y -= step;
componentOld.setLocation(p1);
p2.y -= step;
componentNew.setLocation(p2);
break;
}
case BOTTOM: {
p1.y += step;
componentOld.setLocation(p1);
p2.y += step;
componentNew.setLocation(p2);
break;
}
default:
new RuntimeException("ProgramCheck").printStackTrace();
break;
}
try {
Thread.sleep(500 / (max / step));
} catch (final Exception e) {
e.printStackTrace();
}
}
final long t1 = System.currentTimeMillis();
}
componentOld.setLocation(-10000, -10000);
componentNew.setLocation(0, 0);
}
}
}
I have searched for that problem some time ago.I found this sample code somewhere - saved in my evernote for future reference. This is the shortest way to implement that when I googled that in the past
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class SlidingPanel {
JPanel panel;
public void makeUI() {
panel = new JPanel();
panel.setBackground(Color.RED);
panel.setBounds(0, 0, 400, 400);
JButton button = new JButton("Click");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
((JButton) e.getSource()).setEnabled(false);
new Timer(1, new ActionListener() {
public void actionPerformed(ActionEvent e) {
panel.setLocation(panel.getX() - 1, 0);
if (panel.getX() + panel.getWidth() == 0) {
((Timer) e.getSource()).stop();
System.out.println("Timer stopped");
}
}
}).start();
}
});
panel.add(button);
JFrame frame = new JFrame("Sliding Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
frame.setLayout(null);
frame.add(panel);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new SlidingPanel().makeUI();
}
});
}
}
I've created an Applet that creates a row of buttons, up to 15 buttons, when you push the "add to queue" button. I now want to decrement that row using a for loop. I want it to decrement from left to right. I can only get it to decrement from right to left. I know it has to do with the code in my "Remove" method, but I can't seem to figure out how to fix it. As a newbie I would appreciate any help you can provide.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Vector;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
public class Main extends javax.swing.JApplet {
private final int width = 60;
private final int height = 24;
private final int maxItems = 15;
private int x = 40 + width;
private int y = 260;
private int count = 1;
private JButton jAdd;
private JButton jRemove;
Vector<JButton> stack = new Vector<JButton>();
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
Main inst = new Main();
frame.getContentPane().add(inst);
((JComponent) frame.getContentPane()).setPreferredSize(inst
.getSize());
frame.pack();
frame.setVisible(true);
}
});
}
public Main() {
super();
initGUI();
}
private void initGUI() {
try {
this.setSize(719, 333);
getContentPane().setLayout(null);
{
jAdd = new JButton();
getContentPane().add(jAdd);
jAdd.setText("Add to Queue");
jAdd.setBounds(43, 300, 150, 24);
jAdd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jAddActionPerformed(evt);
}
});
}
{
jRemove = new JButton();
getContentPane().add(jRemove);
jRemove.setText("Remove from queue");
jRemove.setBounds(950, 300, 150, 24);
jRemove.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jRemoveActionPerformed(evt);
}
});
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void jAddActionPerformed(ActionEvent evt) {
if (count > maxItems) {
JOptionPane.showMessageDialog(null, "The queue is full");
return;
}
JButton b = new JButton();
stack.add(0, b);
getContentPane().add(b);
int textCount = count;
b.setText("" +textCount++);
b.setBounds(x, y, width, height);
x = x + width;
count++;
}
private void jRemoveActionPerformed(ActionEvent evt) {
if (stack.isEmpty()) {
JOptionPane.showMessageDialog(null, "The queue is empty");
return;
}
JButton b = stack.remove(0);
this.remove(b);
for(int originalX = 880; originalX < 880; originalX--){
x = 880 - width;
}
repaint();
count--;
}
}
The issue is this:
stack.add(0, b);
You are always adding the new one to the start of the Vector (index 0). Remove that and you will see the behavior you want.
stack.add(b);