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Set JButton to the location of another JButton

I'm trying to move a JButton to the location of another one but the button I want to move moves to a wrong point. My idea is that this happens because I use multiple JPanels. I tried: getLocationOnScreen, getBounds and getLocation, but none of them worked, how to solve it? When an user selects a card on the table or from a player by clicking this card the the target is set, the sender is set by clicking a card from the top panel. playerCardSpotTargetand playerCardSpotSender are both of type Card. When I try to move the for example eight of diamonds this card moves to a point behind the eight and nine of clubs.
Code:
This events belong to the blue cards on the table and the cards for the players(I have to change the name of the event, I know).
private void PlayerOneMouseClicked(java.awt.event.MouseEvent evt){
playerCardSpotTarget=(Card)evt.getSource();
if(playerCardSpotTarget.isBorderPainted()){
playerCardSpotTarget.setBorderPainted(false);
}
else{
playerCardSpotTarget.setBorderPainted(true);
}
}
This event belongs to the cards in the top panel.
private void MouseClicked(java.awt.event.MouseEvent evt) {
playerCardSpotSender=(Card)evt.getSource();
System.out.println(playerCardSpotSender.suit+" "+playerCardSpotSender.kind);
if (playerCardSpotTarget != null && playerCardSpotTarget.isBorderPainted()) {
playerCardSpotSender.setLocation(playerCardSpotTarget.getLocation());
System.out.println(playerCardSpotTarget.getLocationOnScreen());
System.out.println(playerCardSpotSender.getLocationOnScreen());
}
}
Layout for the center panel in the JFrame (BorderLayout.CENTER)
JPanel centerPanelNorth;
JPanel centerPanelCenter;
JPanel centerPanelEast;
JPanel centerPanelSouth;
JPanel centerPanelWest;
JLabel tablePicture;
JPanel centerPanel;
centerPanel=new JPanel(new BorderLayout());
tablePicture = new JLabel(new ImageIcon(this.getClass().getResource(Constants.POKERTABLE_ICON)));
centerPanelNorth=new JPanel();
centerPanelEast=new JPanel();
centerPanelSouth=new JPanel();
centerPanelWest=new JPanel();
centerPanelCenter=new JPanel();
centerPanel.add(centerPanelCenter,BorderLayout.CENTER);
centerPanelCenter.add(tablePicture);
//add
tablePicture.add(boardCard1);
tablePicture.add(boardCard2);
tablePicture.add(boardCard3);
tablePicture.setLayout(new GridBagLayout());
//PLAYER NORTH
centerPanel.add(centerPanelNorth,BorderLayout.NORTH);
centerPanelNorth.add(playerOneCardOne);
centerPanelNorth.add(playerOneCardTwo);
//PLAYER EAST
centerPanel.add(centerPanelEast,BorderLayout.EAST);
centerPanelEast.setLayout(new BoxLayout(centerPanelEast,BoxLayout.X_AXIS));
centerPanelEast.add(playerTwoCardOne);
centerPanelEast.add(playerTwoCardTwo);
//PLAYER SOUTH
centerPanel.add(centerPanelSouth,BorderLayout.SOUTH);
centerPanelSouth.add(playerThreeCardOne);
centerPanelSouth.add(playerThreeCardTwo);
//PLAYER WEST
centerPanel.add(centerPanelWest,BorderLayout.WEST);
centerPanelWest.setLayout(new BoxLayout(centerPanelWest,BoxLayout.X_AXIS));
centerPanelWest.add(playerFourCardOne);
centerPanelWest.add(playerFourCardTwo);
Card.java
public class Card extends JButton{
int suit;
int kind;
boolean known;
String iconPath;
Integer boardPosition;
}

Animating the button movement isn't actually the hardest problem, the hardest problem is trying to move the data about in away in which you can manage it and how to connect the source component with the target...
To start with, you need a means by which you can move a component across container boundaries. While there are probably a few ways to do this, the simplest is to probably use the glass pane of the frame
public class AnimationPane extends JPanel {
public AnimationPane() {
setOpaque(false);
setLayout(null);
}
}
This is nothing special, it's just a JPanel which is transparent and has no layout manager, normally, not recommended, but in the case, we're going to take control..
Now, we need some way to animate the movement...
public enum Animator {
INSTANCE;
private List<IAnimatable> animatables;
private Timer timer;
private Animator() {
animatables = new ArrayList<>(25);
timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
IAnimatable[] anins = animatables.toArray(new IAnimatable[animatables.size()]);
for (IAnimatable animatable : anins) {
animatable.update();
}
}
});
timer.start();
}
public void addAnimatable(IAnimatable animatable) {
animatables.add(animatable);
}
public void removeAnimatable(IAnimatable animatable) {
animatables.remove(animatable);
}
}
public interface IAnimatable {
public void update();
}
public interface IMoveAnimatable extends IAnimatable{
public JComponent getSourceComponent();
public IImportable getImportable();
}
So the Animator is the core "engine", it's basically a Swing Timer which simply calls update on any IAnimatables it might be managing. The intention with this approach is you can have a number of animations running, but it won't degrade the system (greatly) as you only have a single update/timer point.
Now, normally I'd just use something like the Timing Framework or the Trident Framework or even the Universal Tween Engine
The IAnimatable interfaces just define the basic contracts that provide functionality for the animation.
We need to define some kind of contract the defines objects which can take part in the animation process and receive information, or the "target"
public interface IImportable {
public JComponent getView();
public void importValue(String value);
}
public abstract class AbstractImportable extends JPanel implements IImportable {
#Override
public JComponent getView() {
return this;
}
}
Now it occurs to me that we could tap into the pre-existing Transferable API, which would allow you to also implement drag-n-drop (and even copy/cut and paste), this would be used to define a lookup mechanism where you match a given data type with potential targets based on the DataFlavor ... but I'll leave you to investigate how that might work...
The core mechanism basically removes the source component from it's current container, adds it to the AnimationPane, moves the source component across the AnimationPane and then imports the data into the target...
The problem is, you need to translate the location of component from it's current context to the AnimationPane.
A components location is relative to it's parents context. It's relatively easy to do with SwingUtilities.convertPoint(Component, Point, Component)
We calculate the origin point of the source component and the target point, relative to the AnimationPane. We then, on each call to update, calculate the progress of the animation. Instead of using a "delta" movement, we calculate the different between the time we started and a predefined duration (1 second in this case), this generally produces a more flexible animation
public class DefaultAnimatable implements IMoveAnimatable {
public static final double PLAY_TIME = 1000d;
private Long startTime;
private JComponent sourceComponent;
private IImportable importable;
private JComponent animationSurface;
private Point originPoint, destinationPoint;
private String value;
public DefaultAnimatable(JComponent animationSurface, JComponent sourceComponent, IImportable importable, String value) {
this.sourceComponent = sourceComponent;
this.importable = importable;
this.animationSurface = animationSurface;
this.value = value;
}
public String getValue() {
return value;
}
public JComponent getAnimationSurface() {
return animationSurface;
}
#Override
public JComponent getSourceComponent() {
return sourceComponent;
}
#Override
public IImportable getImportable() {
return importable;
}
#Override
public void update() {
if (startTime == null) {
System.out.println("Start");
IImportable importable = getImportable();
JComponent target = importable.getView();
originPoint = SwingUtilities.convertPoint(getSourceComponent().getParent(), getSourceComponent().getLocation(), getAnimationSurface());
destinationPoint = SwingUtilities.convertPoint(target.getParent(), target.getLocation(), getAnimationSurface());
destinationPoint.x = destinationPoint.x + ((target.getWidth() - getSourceComponent().getWidth()) / 2);
destinationPoint.y = destinationPoint.y + ((target.getHeight() - getSourceComponent().getHeight()) / 2);
Container parent = getSourceComponent().getParent();
getAnimationSurface().add(getSourceComponent());
getSourceComponent().setLocation(originPoint);
parent.invalidate();
parent.validate();
parent.repaint();
startTime = System.currentTimeMillis();
}
long duration = System.currentTimeMillis() - startTime;
double progress = Math.min(duration / PLAY_TIME, 1d);
Point location = new Point();
location.x = progress(originPoint.x, destinationPoint.x, progress);
location.y = progress(originPoint.y, destinationPoint.y, progress);
getSourceComponent().setLocation(location);
getAnimationSurface().repaint();
if (progress == 1d) {
getAnimationSurface().remove(getSourceComponent());
Animator.INSTANCE.removeAnimatable(this);
animationCompleted();
}
}
public int progress(int startValue, int endValue, double fraction) {
int value = 0;
int distance = endValue - startValue;
value = (int) Math.round((double) distance * fraction);
value += startValue;
return value;
}
protected void animationCompleted() {
getImportable().importValue(getValue());
}
}
Okay, now this produces a linear animation, which is pretty boring, now if you have plenty of time, you could create an easement like this or just use one of the animation frameworks...
Now, we need to put it together...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class AnimationTest {
public static void main(String[] args) {
new AnimationTest();
}
public AnimationTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
AnimationPane animationPane = new AnimationPane();
LeftPane leftPane = new LeftPane(animationPane);
RightPane rightPane = new RightPane();
leftPane.setImportabale(rightPane);
rightPane.setImportabale(leftPane);
JFrame frame = new JFrame("Testing");
frame.setLayout(new GridLayout(1, 2));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(leftPane, BorderLayout.WEST);
frame.add(rightPane, BorderLayout.WEST);
frame.setGlassPane(animationPane);
animationPane.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class RightPane extends AbstractImportable {
private IImportable source;
private JButton imported;
private String importedValue;
public RightPane() {
setLayout(new GridBagLayout());
setBorder(new LineBorder(Color.DARK_GRAY));
}
public void setImportabale(IImportable source) {
this.source = source;
}
#Override
public void importValue(String value) {
if (imported != null) {
// May re-animate the movement back...
remove(imported);
}
importedValue = value;
imported = new JButton(">> " + value + "<<");
add(imported);
revalidate();
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public class LeftPane extends AbstractImportable {
private IImportable importable;
public LeftPane(AnimationPane animationPane) {
setLayout(new GridBagLayout());
JButton btn = new JButton("Lefty");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
DefaultAnimatable animatable = new DefaultAnimatable(animationPane, btn, importable, "Lefty");
Animator.INSTANCE.addAnimatable(animatable);
}
});
add(btn);
setBorder(new LineBorder(Color.DARK_GRAY));
}
public void setImportabale(IImportable target) {
this.importable = target;
}
#Override
public void importValue(String value) {
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}

Maybe use mousePressed(),when you move the card,you press it until the target.And in the process, you get the information about JButton.getLocation() by the event,and than you need to solve the collision problem between two cards.So it's good!Of course, this is my advice ,you should have better idea!

Java: Repaint in Swing Not Working

I am learning java swing and am having trouble with the following program. It creates a small frame with a quit button at top. The objective is to display coordinates wherever the mouse is clicked. When I click the mouse 2 unwanted things are happening:
the quit button is overridden by the mouse clicks and it no longer responds (instead of responding to event and quitting, it displays coordinates on top of the quit button).
when I click at a new location, the coordinates from the old location persist.
I used removeAll() and revalidate() before doing repaint() based on this discussion but that has not helped. This code is taken from here and the code to says to research online documentation for why this is happening.
Any pointers?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
public class QuitCoordinateTest {
public static void main(String[] args){
GUI gui = new GUI();
}
}
class MyFrame extends JFrame implements ActionListener{
int clickX;
int clickY;
public void paint(Graphics g){
g.drawString("" + clickX + ", " + clickY, clickX, clickY);
}
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
//=======================================================//
class GUI extends MyFrame {
JButton quitButton = new JButton("Quit");
public GUI(){
MyFrame displayWindow = new MyFrame();
displayWindow.setTitle("Title");
/*
JPanel buttonPanel = new JPanel();
buttonPanel.add(quitButton);
displayWindow.getContentPane().add(buttonPanel,BorderLayout.NORTH);
JPanel textPanel = new JPanel();
*/
displayWindow.getContentPane().add(quitButton,BorderLayout.NORTH);
quitButton.addActionListener(displayWindow);
displayWindow.setSize(201,201);
displayWindow.setVisible(true);
// displayWindow.pack();
displayWindow.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
displayWindow.addMouseListener(new MouseProc(displayWindow));
}//end constructor
}//end class GUI definition
//=======================================================//
//This listener class monitors for mouse presses and
// displays the coordinates of the mouse pointer when the
// mouse is pressed on the source object.
class MouseProc extends MouseAdapter{
MyFrame refToWin;
MouseProc(MyFrame inWin){
refToWin = inWin;
}
//Override the mousePressed method to determine and
// display the coordinates when the mouse is pressed.
public void mousePressed(MouseEvent e){
refToWin.removeAll();
refToWin.clickX = e.getX();
refToWin.clickY = e.getY();
//Force the JFrame object to be repainted in order to
// display the coordinate information.
refToWin.removeAll();
refToWin.validate();
refToWin.repaint();
}
}

repaint() is working fine.
Avoid drawing directly on the JFrame.
Instead draw in the protected void paintComponent(Graphics g) method override of a JPanel that is then displayed in your JFrame.
Be sure to call the super's paintComponent(g) method inside of your paintComponent override -- this will erase the old images and is the reason for one of your problems.
Use reasonable comments in your code. Too many comments and too much text distracts and makes understanding your code harder, not easier.
Calling removeAll() on your JFrame will do just that -- remove all components including your button. Why are you calling this? Are you sure that you want to call this method?
A minor nitpick -- you'll want to avoid directly setting the fields of another class, such as your clickX and clickY fields. Instead, make them private, and only allow outside classes to modify them through public methods. While it may not matter much for this small program, it will matter greatly when you start scaling up your programming and create large programs with complex interactions. The key to success here will be to limit and control all communication between classes to avoid hard to detect side effects.
For example, something like...
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
String str = String.format("[%d, %d]", clickX, clickY);
g.drawString(str, clickX, clickY);
}
public int getClickX() {
return clickX;
}
public void setClickX(int clickX) {
this.clickX = clickX;
}
public int getClickY() {
return clickY;
}
public void setClickY(int clickY) {
this.clickY = clickY;
}
For example
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class DetectClicks extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private int clickX;
private int clickY;
public DetectClicks() {
MyMouseListener mouseAdapter = new MyMouseListener(this);
addMouseListener(mouseAdapter);
addMouseMotionListener(mouseAdapter); // to allow dragging!
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
String str = String.format("[%d, %d]", clickX, clickY);
g.drawString(str, clickX, clickY);
}
public int getClickX() {
return clickX;
}
public void setClickX(int clickX) {
this.clickX = clickX;
}
public int getClickY() {
return clickY;
}
public void setClickY(int clickY) {
this.clickY = clickY;
}
private static void createAndShowGui() {
DetectClicks mainPanel = new DetectClicks();
JFrame frame = new JFrame("DetectClicks");
frame.setDefaultCloseOperation(JFrame.DISPOSE_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();
}
});
}
}
class MyMouseListener extends MouseAdapter {
private DetectClicks detectClicks;
public MyMouseListener(DetectClicks detectClicks) {
this.detectClicks = detectClicks;
}
#Override
public void mousePressed(MouseEvent evt) {
showPoint(evt);
}
#Override
public void mouseDragged(MouseEvent evt) {
showPoint(evt);
}
private void showPoint(MouseEvent evt) {
detectClicks.setClickX(evt.getX());
detectClicks.setClickY(evt.getY());
detectClicks.repaint();
}
}

Your event is getting consumed by the handler that prints the coordinates, you need to redispatch the event so that the button can see it. You can do it like this, inside the coordinate display event handler:
Component c = e.getComponent();
c.getParent().dispatchEvent( e );
Also, I'd be tempted to use the glass pane of the frame, and put a JLabel on it with the co-ordinates rather than messing with the paint method.

you don't have to use any of repaint(),invalidate() etc.
i highly recommend to use
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//TODO udpdate UI compontents, layouts etc.
}
});
this guarantees that UI components update on real time. Because we don't know when the system update UI hierarchy so we can't force it. This allow system to determine by it's self.

Java swing component to show image grid

Its been a while since i built a desktop JAVA application.. after lots of documentation and doing implementation tests, i still have not found an image grid solution.
Either Java lacks such a ready-to-use component (?!) or you tell me to brush up my google-fu. :)
I have a very simple technical premises: a JDialog that allows the user to pick an image. Input is a Map<Integer, String> list that holds filenames. Output is the Integer key the user chose. GUI also is simple: user chooses 1 image using mouse or keyboard, and dialog closes. All images are 80x80px and loaded from filename, not a resource.
I tried several approaches so far this morning:
Search for components/widgets that show scrollable imagegrid that can flow to the left. (no dice)
Search for components/widgets that show scrollable imagegrid (no dice)
Search for any components/widgets/gui-libs (no dice .. do these even exist?!)
Try and implement myJList.setModel(), but i cant get it to just take my Map<> and show thumbnails. (overcomplicates!)
Try and implement myJPanel.setlayout(new FlowLayout(..)) with several myJPanel.add(new JButton(..)) which just creates a bunch of JButton on a JPanel, which each need a event handler. I wonder how scrolling and keyboard input is going to work out, and how i'm supposed to keep/reference my Map<> key values. (overcomplicates?)
In lieu of your answer, i am now working on the latter, which should work but i cant believe everyone needs to reinvent the same GUI wheel here. How to have the user select an image from my Map<Integer, String>? Are there JAVA libraries/widgets/components that i should look to avoid this?
I hope this isn't being modded down, i have no working implementation with error to show you guys.. this question is about how/where to find the components or what approaches would be better. Its 2014 and i cant believe that JAVA still requires me to build my own "GUI component" just to see some images.. not even Delphi or Mono does that.

If all you want is a grid of images, and having them selectable, consider using a JList, filling it with appropriate ImageIcons, and giving it a ListSelectionListener. In the Listener you can close the enclosing dialog when a selection has been made.
You state:
Try and implement myJList.setModel(), but i cant get it to just take my Map<> and show thumbnails. (overcomplicates!)
You need to use your Map to populate your ListModel, and set that Model to the JList's model.
For example:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dialog.ModalityType;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
#SuppressWarnings("serial")
public class ImageGridPanel extends JPanel {
public static final String PATH = "http://images-2.drive.com.au/2011/";
public static final String[] CARS = {
"04/15/2308961/giulietta_1024-80x80.jpg",
"11/18/2781958/audi-a1-sportback_600-80x80.jpg",
"12/23/2856762/fiat-500-80x80.jpg",
"01/12/2129944/Honda-Civic-Sedan-concept-1_600-80x80.jpg",
"12/23/2856581/mini-roadster-80x80.jpg",
"12/23/2856571/hyundai-veloster-80x80.jpg",
"12/23/2856771/hyundai-i30-80x80.jpg",
"12/23/2856580/mini-coupe-80x80.jpg" };
private DefaultListModel<Car> carModel = new DefaultListModel<>();
final JTextField textField = new JTextField(20);
public ImageGridPanel() {
for (String carPath : CARS) {
String path = PATH + carPath;
try {
URL imgUrl = new URL(path);
BufferedImage img = ImageIO.read(imgUrl);
ImageIcon icon = new ImageIcon(img);
String name = carPath.substring(carPath.lastIndexOf("/"));
name = name.substring(1, name.lastIndexOf("-"));
carModel.addElement(new Car(name, icon));
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
}
ShowGridAction showAction = new ShowGridAction("Car Grid", carModel);
JButton showGridBtn = new JButton(showAction);
add(showGridBtn);
add(textField);
}
private class ShowGridAction extends AbstractAction {
private CarGridPanel carGridPanel;
public ShowGridAction(String name, DefaultListModel<Car> carModel) {
super(name);
carGridPanel = new CarGridPanel(carModel);
}
public CarGridPanel getCarGridPanel() {
return carGridPanel;
}
#Override
public void actionPerformed(ActionEvent e) {
Window win = SwingUtilities.getWindowAncestor((Component) e.getSource());
JDialog dialog = new JDialog(win, "Cars", ModalityType.APPLICATION_MODAL);
dialog.add(carGridPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
int x = dialog.getLocation().x;
int y = dialog.getLocation().y - 150;
dialog.setLocation(x, y);
dialog.setVisible(true);
Car selectedCar = carGridPanel.getSelectedCar();
if (selectedCar != null) {
textField.setText(selectedCar.getName());
}
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("ImageGrid");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ImageGridPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class Car {
String name;
Icon icon;
public Car(String name, Icon icon) {
this.name = name;
this.icon = icon;
}
public String getName() {
return name;
}
public Icon getIcon() {
return icon;
}
}
#SuppressWarnings("serial")
class CarGridPanel extends JPanel {
private JList<Car> carList = new JList<>();
private Car selectedCar;
public CarGridPanel(ListModel<Car> model) {
carList.setModel(model);
carList.setLayoutOrientation(JList.HORIZONTAL_WRAP);
carList.setVisibleRowCount(2);
carList.setCellRenderer(new DefaultListCellRenderer() {
#Override
public Component getListCellRendererComponent(JList<?> list,
Object value, int index, boolean isSelected, boolean cellHasFocus) {
if (value != null) {
Car carValue = (Car) value;
value = carValue.getIcon();
} else {
value = "";
}
return super.getListCellRendererComponent(list, value, index,
isSelected, cellHasFocus);
}
});
setLayout(new BorderLayout());
add(new JScrollPane(carList));
carList.addListSelectionListener(new ListListener());
}
public Car getSelectedCar() {
return selectedCar;
}
private class ListListener implements ListSelectionListener {
#Override
public void valueChanged(ListSelectionEvent e) {
selectedCar = carList.getSelectedValue();
Window win = SwingUtilities.getWindowAncestor(CarGridPanel.this);
win.dispose();
}
}
}

No, Java doesn't have what you want.
Java is a general-purpose programming language, not a toolset, particularly not a specialized desktop GUI toolset. This is not a denigration of the language, just a statement of a purpose that it was not developed to fulfill.
If Delphi or Mono or anything has your particular widget, then I suggest you program in that, instead. This is not a denigration of you, just an observation that, if you do not want to put together the widget you want from lower-level components and code, then Java is not the right language/tool for you to use to do it.
As for not believing that Java "still requires" you to build your own component, I can only say that you don't get to choose which languages provide which features. I'm just as glad Java isn't littered with your component and the hundreds of others that people like you would come up with that they think Java should provide. It's big enough as it is.

Create a Swing component based on another but with different API

I would like to create a new Swing JComponent based on an existing one, but with a different API. In other words, I don't want to extend the existing component, because I don't want it's API to be accessible.
Here an example to clarify my needs:
A replacement of the JCheckBox which show two buttons ON/OFF. This could be based on a pre-configured JCommandButtonStrip (some info here) but exposing exactly the same API of JCheckBox. The configuration of the JCommandButtonStrip must not be altered.
What is the best approach for such a problem?
Clarifications:
As someone pointed out, what I wrote about API is not clear.
Of course JComponent have a number of public fields and methods which will be available for each sub-class. Then each sub-class of JComponent may add its own public fields and methods. For example, AbstractButton adds the isSelected() method, while JCommandButtonStrip adds the getButtonCount() method.
So, what I meant is: I want to create a new JComponent sub-class MyJComponent, which is based on an existing one ExistingJComponent. I don't want the public methods of ExistingJComponent, except those of JComponent, to be exposed by my class MyJComponent. Then I want to add some public methods to MyJComponent.
Please note that I'm not looking for an alternative to the JCommandButtonStrip/JCheckBox example. I'm interested in a general approach to such a problem.

You can create a new class which extends JComponent then inside the constructor insert a checkbox into itself.
public class MyCoolCheckbox extends JComponent{
private JCheckBox checkbox;
public MyCoolCheckbox(String label) {
checkbox= new JCheckBox(label);
this.setLayout(new BorderLayout());
this.add(checkbox, BorderLayout.CENTER);
}
}
This is obviously incomplete and you may need to delegate certain methods to the child. It might get messy. IDEs like IntelliJ IDEA will generate all this for you if you hit alt-ins (by default) then delegate, then select the checkbox member and pick the entries you want to delegate. For example:
public void setForeground(Color fg) {
checkbox.setForeground(fg);
}
public void setBackground(Color bg) {
checkbox.setBackground(bg);
}
public Color getForeground() {
return checkbox.getForeground();
}
public Color getBackground() {
return checkbox.getBackground();
}
Keep in mind that because the child is within the Swing component tree, other code will have access to the children even though they are marked private.
((JCheckBox)myCoolCheckbox.getComponents()[0]).setSelected(true);

As shown here, you can use two instances of JToggleButton in a ButtonGroup to "show two buttons ON / OFF." The ButtonGroup causes only one button in the group to be selected at a time. The following change is illustrated:
private final JLabel label = new JLabel(" \u2713 ");

Based on this picture of JCommandButtonStrip:
I think you are looking for JToggleButton as #trashgod suggested, but I'm not sure about buttons group given the current description of your "problem". If you need buttons group then use it.
Anyway my answer points to this line:
This could be based on a pre-configured JCommandButtonStrip (some info
here) but exposing exactly the same API of JCheckBox.
Once again it's not clear if you're trying to do a buttons bar such as JCommandButtonStrip or you want to do something else. However you can make your own component extending from JComponent and delegate only those methods that are needed from the outside. For example let's say you want to do a buttons bar such as JCommandButtonStrip. Then you can have:
One class extending from JComponent: your buttons bar.
Another one providing an API to add "commands" to the buttons bar.
Note: There's already a JToolBar component which can perfectly be used without reinvent the wheel. The example below is just to show you that you can control the API offered to the developers.
MyCommandBar.java
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Map;
import javax.swing.AbstractButton;
import javax.swing.Action;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComponent;
import javax.swing.JPanel;
import javax.swing.JToggleButton;
import javax.swing.event.ChangeListener;
public class MyCommandBar extends JComponent {
private final JPanel content;
private final Map<String, CommandItem> map = new HashMap<>();
public MyCommandBar() {
super();
content = new JPanel(new GridLayout(1, 0));
content.setOpaque(false);
setLayout(new FlowLayout());
add(content);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics graphics = g.create();
graphics.setColor(getBackground());
graphics.fillRect(0, 0, getWidth(), getHeight());
graphics.dispose();
}
public void addCommandItem(String actionCommand, CommandItem commandItem) {
if(map.get(actionCommand) != null) {
removeCommandItem(actionCommand);
}
content.add(commandItem.getComponent());
map.put(actionCommand, commandItem);
}
public void removeCommandItem(String actionCommand) {
CommandItem commandItem = map.get(actionCommand);
if(commandItem != null) {
content.remove(commandItem.getComponent());
content.revalidate();
content.repaint();
map.remove(actionCommand);
}
}
public CommandItem getCommandItem(String actionCommand) {
return map.get(actionCommand);
}
public static class CommandItem {
public static final int TOGGLE_BUTTON_STYLE = 0;
public static final int CHECK_BOX_STYLE = 1;
public static final int DEFAULT_BUTTON_STYLE = 2;
private final AbstractButton component;
public CommandItem(String text, boolean state, Icon icon, int style) {
switch(style) {
case TOGGLE_BUTTON_STYLE : component = new JToggleButton(text, icon, state); break;
case CHECK_BOX_STYLE : component = new JCheckBox(text, icon, state); break;
default: component = new JButton(text, icon);
}
}
protected AbstractButton getComponent() {
return component;
}
public void addActionListener(ActionListener listener) {
component.addActionListener(listener);
}
public void addChangeListener(ChangeListener listener) {
component.addChangeListener(listener);
}
public void setAction(Action action) {
component.setAction(action);
}
}
}
Example of use
This code snippet shows how MyCommandBar class should be used:
MyCommandBar commandBar = new MyCommandBar();
commandBar.setBorder(BorderFactory.createLineBorder(Color.black, 1));
commandBar.addCommandItem("BOLD", new MyCommandBar.CommandItem("<html><b>Bold</b></html>", true, null, MyCommandBar.CommandItem.TOGGLE_BUTTON_STYLE));
commandBar.addCommandItem("ITALICS", new MyCommandBar.CommandItem("<html><i>Italics</i></html>", false, null, MyCommandBar.CommandItem.CHECK_BOX_STYLE));
commandBar.addCommandItem("UNDERLINE", new MyCommandBar.CommandItem("<html><u>Underline</u></html>", false, null, MyCommandBar.CommandItem.DEFAULT_BUTTON_STYLE));
And you'll see something like this:

You can create MyJComponent subclass of JComponent with a private field that references a forwarding class for ExistingComponent.
The interactions with ExistingComponent are done with the forwarding class through methods of MyJComponent, and you are free to add more methods to MyJComponent.
Please see Effective Java item 16, for the delegation pattern used with the forwarding class.

Where can I put mouse event handling code so that it is out of the way but can still manipulate objects?

I'm learning Java here and trying to get to grips with classes and how best to catch mouse events etc. for my little game, so please be patient and give my some hints.
The main class of my project extends JFrame and upon construction adds to itself an object of a class which extends JPanel. This JPanel covers the whole window and it is this I am using to paint stuff to the screen. Then I have a class called Scene which extends nothing but which stores all the references to the current objects on the screen and is responsible for compiling them all and passing them back to the JPanel. I didn't want to put the full mouse event code in the JPanel because it would be so messy so I though I'd create another class for that called MEs and let each scene have one. My thinking was, this way each mes object can access the objects in each scene easily. So my code is looking like this:
class DPanel extends JPanel {
Scene scCurrent;
public DPanel() {
scCurrent = new Scene();
addMouseMotionListener(new MouseAdapter() {
public void mouseMoved(MouseEvent me) { scCurrent.mes.moved(me); }
});
...
}
...
but of course, inside scCurrent.mes.moved() I don't even know how to change the cursor. It doesn't recognise setCursor() in there. How can I change the cursor and access objects that are higher up the tree like I'd need to to switch scene? Or is there some other place I can tuck my mouse event handling code that will not bumph-out out my JPanel?

You are trying to separate out the control code from the view (GUI) code, and this is a good thing. A solution is to give the view code public methods that allow outside code to change its state, and give the control classes a reference to the view so that the controls (i.e., MouseListeners, MouseMotionListeners, ActionListeneres) can call these methods on a proper reference and change the view's states.
Edit 1
It may be easier just to show you an example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class ViewControl {
private static void createAndShowGui() {
View view = new View();
Control control = new Control(view);
view.addMouseAdapter(control);
JFrame frame = new JFrame("ViewControl");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(view);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class View extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private List<Point> points = new ArrayList<Point>();
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (points.size() > 1) {
for (int i = 0; i < points.size() - 1; i++) {
int x1 = points.get(i).x;
int y1 = points.get(i).y;
int x2 = points.get(i + 1).x;
int y2 = points.get(i + 1).y;
g.drawLine(x1, y1, x2, y2);
}
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public void addMouseAdapter(MouseAdapter adapter) {
// addMouseListener(adapter);
addMouseMotionListener(adapter);
}
public void addPoint(Point p) {
points.add(p);
repaint();
}
}
class Control extends MouseAdapter {
private View view;
public Control(View view) {
this.view = view;
}
#Override
public void mouseDragged(MouseEvent e) {
view.addPoint(e.getPoint());
}
}