I need to display chessboard. I have a BoardPanel class which extends JPanel and a GamePanel (also extending JPanel) class containing BoardPanel. GamePanel fills all the application frame.
I want BoardPanel to always be a square with size equal to the minimum of GamePanel's width and height (if GamePanel's width is greater than height there should be empty space on the left and right, if it's smaller there should be empty space on top and bottom). It's also important that BoardPanel should be displayed in the center of parent panel.
I wrote sth like this:
public GamePanel() {
setLayout(new BorderLayout(0, 0));
boardPanel = new BoardPanel(...);
this.add(boardPanel, BorderLayout.CENTER);
...
}
and in BoardPanel:
public void paintComponent(Graphics g) {
super.paintComponent(g);
int size = Math.min(this.getParent().getHeight(), this.getParent().getWidth());
this.setSize(size, size);
...
}
It resizes well, but chessboard is always displayed in top left corner of GamePanel (all the empty space is displayed on bot or right) and I don't know how to fix it.
Any help? Thanks in advance!
Center it using a GridBagLayout.
import java.awt.*;
import javax.swing.*;
public class CenteredPanel {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
JPanel gui = new JPanel(new GridBagLayout());
JPanel square = new SquarePanel();
square.setBackground(Color.RED);
gui.add(square);
JFrame f = new JFrame("SquareBoard");
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.add(gui);
f.setMinimumSize(new Dimension(400,100));
f.pack();
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
class SquarePanel extends JPanel {
#Override
public Dimension getPreferredSize() {
Container c = this.getParent();
int size = Math.min(c.getHeight(), c.getWidth());
Dimension d = new Dimension(size,size);
return d;
}
}
No need for new BorderLayout(0,0) simply use default constructor for BorderLayout
Dont call setSize() rather override getPreferredSize() of JPanel like so:
#Override
public void getPreferredSize() {
int size = Math.min(this.getParent().getHeight(), this.getParent().getWidth());
return new Dimension(size,size);
}
also its never good to do work in your paintComponent as this should be used exclusively for painting only.
If the above does not work I'd suggest a SSCCE to illustrate specific problems you might have
Related
Beginner programming student here. Trying to simply create JFrame object that allows me to click on the boundaries of the window and display the coordinates where I click. However, whenever I click a new location, the previous coordinates need to disappear. I have been told that one way to do this is by adding a JPanel to the center of the JFrame object. However when I do so I am getting an error that says that I am adding a window to a container. I may be extending something incorrectly from what I have read but I can't seem to figure it out.
public class Proj07 {
public static void main(String[] args){
new Proj07Runner();
}
}
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Proj07Runner{
GUI gui = new GUI();
}
class MyFrame extends JFrame{
int XCoor;
int YCoor;
public void paint(Graphics g){
g.drawString("x = " + XCoor + ", y = " + YCoor, XCoor, YCoor);
}
}
class GUI{
public GUI(){
MyFrame displayWindow = new MyFrame();
displayWindow.setSize(300,100);
displayWindow.setTitle("Insert name here");
displayWindow.addWindowListener(new WProc1());
JPanel myPanel = new JPanel();
displayWindow.getContentPane().add(myPanel, "Center");
displayWindow.setVisible(true);
}
}
class MouseProc extends MouseAdapter{
public void mousePressed(MouseEvent e){
((MyFrame)e.getComponent()).XCoor = e.getX();
((MyFrame)e.getComponent()).YCoor = e.getY();
e.getComponent().repaint();
}
}
class WProc1 extends WindowAdapter{
public void windowClosing(WindowEvent e){
System.exit(0);
}
}
Thank you guys for your help!
I am not 100% sure but I think the problem is where you put the listener:
You need to do everything on the JPanel, not the frame that is the container, so you should replace the declares with:
MyFrame displayWindow = new MyFrame();
displayWindow.setSize(300,100);
displayWindow.setTitle("Insert name here");
displayWindow.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel myPanel = new JPanel();
myPanel.setSize(300,100);
myPanel.addMouseListener(new myMouse)
displayWindow.getContentPane().add(myPanel, "Center");
displayWindow.setVisible(true);
And then create a mouseListener instead of a mouseAdapter to add in the JPanel.
Also remove the last WindowsAdapter thing, just use exitonclose.
Edit:
When it comes down to what the frame should do it should only contain the panel, so you also need to move everything you were doing on the frame to the panel (such as the public void paint() and stuff).
I would go as far as saying that if you want to add multiple panels on a frame, you should consider putting all panels inside another panel (as a container) and then putting that panel inside the frame.
i just started studying gui in java. i am now able to create windows with specific sizes while extending JFrame. however, i came to read posts from here that it is better not to extend JFrame. then i tried to create a window by setting the size in the JPanel instead, but the setSize doesn't seem to work (my code must lack something)
here's my code for my frame
import javax.swing.JFrame;
public class MyFrame{
private JFrame mainFrame;
private MyPanel mainPanel;
public MyFrame(){
mainFrame = new JFrame();
mainPanel = new MyPanel(50, 50);
mainFrame.add(mainPanel);
mainFrame.setVisible(true);
}
}
and here's my code for my panel
import javax.swing.JPanel;
public class MyPanel extends JPanel{
public MyPanel(int i, int j){
setSize(i, j);
}
}
i tried adding frame.pack() in my Frame class, because i thought the frame, not having it's size set, is too small for the panel to be seen -i was wrong
what's lacking in my code?
what's lacking in my code?
A preferred size for the custom component (Panel) for starters. #Override getPreferredSize() to return a logical value.
Then pack() the frame to ensure it is the smallest size needed to display the panel and any other components.
So, something like this:
import javax.swing.*;
public class Application {
private JFrame frame;
private CustomPanel panel;
public Application() {
frame = new JFrame();
// next 2 lines, just a good idea
frame.setLocationByPlatform(true);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// at 50x50, the title bar on Windows is wider!
panel = new CustomPanel(200, 200);
frame.add(panel);
// make the frame smallest it can be and still show components
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new Application();
}
};
SwingUtilities.invokeLater(r);
}
}
class CustomPanel extends JPanel {
public CustomPanel(int w, int h) {
setPreferredSize(new java.awt.Dimension(w, h));
}
}
I have a JFrame. It uses a JPanel as its content pane, and that JPanel uses GridBagLayout as its LayoutManager. That JPanel contains two more items: a button, and another JPanel. On program start, an image is loaded from file into the lowest-level JPanel as a BufferedImage using ImageIO.read(...). Here is where everything goes to pieces.
The image loads correctly, I can see a small corner of it on screen (14px square as specified in debugger). There is nothing I can figure out that will cause the layout to grow and fit the entire image in the lowest level JPanel on screen. The image in debuggers shows correct size of 500px. The preferred size of the CardImagePanel shows up correctly as the same size as the image. But the layout will not respect the preferred size unless I manually set the CardImagePanel size using setSize(...) which I'm pretty sure is not supposed to be necessary with GBL.
I have tried putting revalidate() and repaint() calls on every single JFrame, JPanel, layout, grid bag, image, etc throughout the entire program and just can't find the correct place or time to call them to make this thing work. Currently I've been trying to just let the image load incorrectly and use the button to force revalidation and repaint, but even this explicit call is not doing anything.
I'm losing my mind, I'll do anything to get this thing working.
Here is all my code for the whole stupid thing (minus imports and package specification.
P1s1.java:
public class P1s1 {
public static void main(String[] args) {
// TODO code application logic here
build();
}
public static void build()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(640, 480));
frame.setContentPane(new GuiPanel(frame));
frame.setVisible(true);
}
}
GuiPanel.java:
public class GuiPanel extends JPanel {
JFrame parentFrame;
JButton imageLoaderButton;
CardImagePanel cardImagePanel;
LayoutManager layout;
GridBagLayout gridBagLayout;
GridBagConstraints constraints;
public GuiPanel(JFrame frame)
{
parentFrame = frame;
constraints = new GridBagConstraints();
gridBagLayout = new GridBagLayout();
layout = gridBagLayout;
this.setLayout(layout);
this.setBorder(BorderFactory.createLineBorder(Color.black));
setupImageLoaderButton(imageLoaderButton);
cardImagePanel = new CardImagePanel();
this.add(cardImagePanel);
}
private void setupImageLoaderButton(JButton button)
{
button = new JButton("Click to load image!");
ActionListener imageLoaderListener;
imageLoaderListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
System.out.println("Button clicked.");
cardImagePanel.revalidate();
cardImagePanel.repaint();
GuiPanel.this.revalidate();
GuiPanel.this.repaint();
parentFrame.revalidate();
parentFrame.repaint();
}
};
button.addActionListener(imageLoaderListener);
this.add(button);
}
}
CardImagePanel.java:
public class CardImagePanel extends JPanel {
BufferedImage cardImage;
public CardImagePanel()
{
this.setBorder(BorderFactory.createLineBorder(Color.black));
try {
cardImage = ImageIO.read(new File("c:\\dev\\cards\\2_of_clubs.png"));
this.setPreferredSize(new Dimension(cardImage.getWidth(), cardImage.getHeight()));
} catch (IOException ex) {
System.out.println("Exception trying to load image file.");
}
}
// The getPreferredSize() override was suggested by MadProgrammer.
// It did not solve the issue, but see MadProgrammer's updated,
// accepted answer below for the correct solution. The rest of the
// code reflects my original attempt to solve the issue.
#Override
public Dimension getPreferredSize()
{
return cardImage != null ? new Dimension(cardImage.getWidth(), cardImage.getHeight()) : super.getPreferredImage();
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(cardImage, 0, 0, this);
}
}
GridBagLayout relies on a component telling it what size it would like to be (along with it's minimum and maximum size when it's relievent). You need to override the getPreferredSize method of the CardImagePanel, returning the size you would like the component to be
public class CardImagePanel extends JPanel {
BufferedImage cardImage;
public CardImagePanel() {
this.setBorder(BorderFactory.createLineBorder(Color.black));
try {
cardImage = ImageIO.read(new File("c:\\dev\\cards\\2_of_clubs.png"));
} catch (IOException ex) {
System.out.println("Exception trying to load image file.");
}
}
#Override
public Dimension getPreferredSize() {
return cardImage != null ? new Dimension(cardImage.getWidth(), cardImage.getHeight()) : super.getPreferredSize();
}
#Override
public Dimension getMinimumSize() {
return getPreferredSize();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(cardImage, 0, 0, this);
}
}
Have a look at How to Use GridBagLayout for more details
You CardImagePanel has no preferred size, so the layout manager doesn't know how to handle the size properly.
A couple of solutions:
There is no need to create a custom class to display the image. Just use a JLabel to display the image. The JLabel will return the preferred size of the image.
If you do use the CardImagePane, then you need to override the getPreferredsize() method of the CardImagePanel to return the size of the image.
This is a noob question.
We are being taught applets in class, and I was trying something on my own.
The following is the code
import java.awt.*;
import javax.swing.*;
class controls extends JPanel{
#Override public void paintComponent(Graphics g) {
g.drawOval(50, 50, 50, 50); // <-- draws an oval on the panel
}
}
public class test extends JApplet{
public void init(){
final JPanel stage = new JPanel();
final JPanel controlPanel = new controls();
final JPanel banner = new JPanel();
final JLabel name = new JLabel("Test", JLabel.CENTER);
this.setLayout(new BorderLayout());
banner.setBackground(Color.CYAN);
banner.add(name);
this.add(controlPanel, BorderLayout.WEST);
this.add(banner, BorderLayout.NORTH);
}
}
As far as I understand, paintComponent() need not be called explicitly.
The controls class works well when used alone.
I mean the following code works.
public class test extends JApplet{
public void init(){
JPanel controlPanel = new controls();
this.add(controlPanel);
}
}
I am not able to understand the difference. Why does the same code work in this case, and not in the previous?
Thank you.
Override public Dimension getPreferredSize() (and return a new Dimension) in the controls class. When putting components in WEST the width will be determined by the preferredSize. If you don't override getPreferredSize, the preferred size will be 0. The CENTER will take up the rest of the space, after the WEST, ect is calculated. The second case works because it is in the CENTER of the default BorderLayout
I'm basically trying to draw a JComponent inside another by calling the second component's paint passing it the first component's Graphics.
I'm trying to create a GUI editor, (reinventing the wheel, I know, it's just a proof of concept)
So I have a class that extends JPanel where I want to draw components from a VectorControls.
So far I got this method in my extended JPanel:
#SuppressWarnings("serial")
public class Sketch extends JPanel {
private Vector<JComponent> controls = new Vector<JComponent>();
public Sketch() {
super();
this.setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
}
public void addControl(JComponent c) {
Dimension d = new Dimension(100,50);
c.setPreferredSize(d);
c.setMinimumSize(d);
c.setMaximumSize(d);
controls.add(c);
this.repaint();
this.revalidate();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
for(int i=controls.size()-1; i>=0; i--) {
JComponent c = controls.get(i);
c.paint(g);
}
}
}
I'm building/attaching the Sketch panel like this:
public GUIEditor() {
mainFrame = new JFrame("GUI EDITOR");
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Sketch mainPanel = new Sketch();
mainPanel.setPreferredSize(new Dimension(640,480));
GridBagLayout gbl = new GridBagLayout();
GridBagConstraints gbc = new GridBagConstraints();
mainFrame.setLayout(gbl);
JPanel toolsPanel = new JPanel();
toolsPanel.setPreferredSize(new Dimension(160,480));
toolsPanel.setLayout(new GridLayout(0,1));
for(Control c : toolBoxItems ) {
AbstractAction action = new ToolBoxButtonAction(mainPanel, c.type);
JButton b = new JButton(action);
b.setText(c.title);
toolsPanel.add(b);
}
gbc.gridx = 0;
gbc.gridy = 0;
gbl.setConstraints(mainPanel, gbc);
mainFrame.add(mainPanel);
gbc.gridx = 1;
gbc.gridy = 0;
gbl.setConstraints(toolsPanel, gbc);
mainFrame.add(toolsPanel);
mainFrame.pack();
mainFrame.setLocationRelativeTo(null);
mainFrame.setVisible(true);
}
Inside ToolBoxButtonAction, basically I'm doing this:
public void actionPerformed(ActionEvent e) {
try {
sketch.addControl(control.newInstance());
} catch (InstantiationException e1) {
e1.printStackTrace();
} catch (IllegalAccessException e1) {
e1.printStackTrace();
}
}
but I'm writing this because it doesn't work.
Any ideas on how to achieve this?
I'm basically trying to draw a JComponent inside another by calling the second component's paint passing it the first component's Graphics.
Components can only be painted when the component has non-zero size. Normally the size of a component is determined by the layout manager.
Your basic code looks reasonable, but unless you have code to size and locate the components you won't see anything. If you just set the size then all components will paint on top of one another.
Or the problem may be that your parent panel doesn't have a size so it is not even painted. The default FlowLayout uses the preferred size of the child components to determine the panels size. Since you don't add components directly to the panel there are no child components so the preferred size will be 0. When you reinvent the wheel you need to reinvent everything.
Without a SSCCE the context of how you use this code is unknown to all we can do is guess.
Edit:
Create a SSCCE when you have a problem and get it working with hard coded values before trying to get it to work dynamically. Something like:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class Sketch extends JComponent
{
private Vector<JComponent> controls = new Vector<JComponent>();
public void addControl(JComponent c)
{
c.setSize(100, 50);
int location = controls.size() * 50;
c.setLocation(location, location);
controls.add(c);
repaint();
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
for(int i=controls.size()-1; i>=0; i--)
{
JComponent c = controls.get(i);
Point location = c.getLocation();
g.translate(location.x, location.y);
c.paint(g);
g.translate(-location.x, -location.y);
}
}
private static void createAndShowUI()
{
Sketch sketch = new Sketch();
sketch.addControl( new JButton("button") );
sketch.addControl( new JTextField(10) );
sketch.addControl( new JCheckBox("Checkbox") );
JFrame frame = new JFrame("Sketch");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( sketch );
frame.setSize(400, 400);
frame.setLocationByPlatform( true );
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowUI();
}
});
}
}
Some time ago, I've written a framework for such tasks. Maybe you find it useful (the library is Open Source):
Tutorial:
http://softsmithy.sourceforge.net/lib/current/docs/tutorial/swing/customizer/index.html
Javadoc:
http://softsmithy.sourceforge.net/lib/current/docs/api/softsmithy-lib-swing-customizer/index.html
Info about the latest release:
http://puces-blog.blogspot.ch/2012/11/news-from-software-smithy-version-03.html