when I run this code PaintComponent is never called because the "painted" message is never printed and I do not know why? can anyone help?
public class DisplayManager extends JPanel {
public static final int WIDTH = 700, HEIGHT = 900;
public Bottle bottle1 = new Bottle("res/bottleimage.png");
public Slider slider1 = new Slider();
public void initDisplay()
{
JFrame frame = new JFrame();
JPanel panel = new JPanel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(WIDTH, HEIGHT));
frame.add(panel);
frame.setVisible(true);
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
bottle1.imageIcon.paintIcon(this, g, 50, 50);
System.out.println("painted");
}
}
There are a couple of problems with the basic code:
as already mentioned you need to add an instance of your DisplayManager class to a frame or panel.
When you do custom painting you need to override the getPreferredSize() method of the component to return your desired size. Currently the preferred size of your component is (0, 0).
The suggestion to add the DisplayManager to the frame only works because the default layout manager is a BorderLayout and by default is added to the CENTER of the layout which means it get all the available space in the frame.
However if you use:
frame.add(this, BorderLayout.PAGE_START);
you won't see the component size it has a size of (0, 0);
Related
I am trying to display two different images on my screen. one of which is a banner that goes at the top of my JFrame, and another that I just placed randomly below the banner for testing purposes. The issue I am having is that while I can display a single image on the screen by adding an object of class WindowStructure to my window, I am not able to display more than one image at a time. Only the last image added to the window is displayed on the screen:
Here is the window class:
import javax.swing.JFrame;
public class Window extends JFrame {
public Window(String name) {
super(name);
setSize(1200, 700);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
WindowStructure banner = new WindowStructure("Beatles Logo.jpg", 0, 0, getWidth(), 75);
WindowStructure fireball = new WindowStructure("fireball.png", 100, 100, 100, 100);
add(banner); //banner
add(fireball);
setVisible(true);
while(true){
repaint();
}
}
public void paint(Graphics g
) {
super.paintComponents(g);
}
}
Here's the actual class that creates the image:
public class WindowStructure extends JPanel {
ImageIcon imageIcon;
int xLoc, yLoc, xSize, ySize;
public WindowStructure(String bannerImg, int xLoc, int yLoc, int xSize, int ySize){
URL bannerImgURL = getClass().getResource(bannerImg);
imageIcon = new ImageIcon(bannerImgURL);
this.xLoc = xLoc;
this.yLoc = yLoc;
this.xSize = xSize;
this.ySize = ySize;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(imageIcon.getImage(), xLoc, yLoc, xSize, ySize, null);
}
}
The default layout manager for JFrame is BorderLayout.
As the documentation says: "BorderLayout interprets the absence of a string specification the same as the constant CENTER". For instance:
add(banner); // Same as p.add(banner, BorderLayout.CENTER);
add(fireball); // Same as p.add(fireball, BorderLayout.CENTER);
You can fix this if you specify the location as a second argument to add():
add(banner, BorderLayout.NORTH);
add(fireball, BorderLayout.CENTER);
Or you can use another layout manager for the JFrame by invoking setLayout(LayoutManager) in your Window class constructor.
public class Window extends JFrame {
public Window(String name) {
super(name);
setLayout(new FlowLayout()); // or another the layout that best fit your needs...
...
Guide about layout managers: http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
The JFrame javadocs state that the default layout manager used is BorderLayout. To add multiple components, you have to specify a different place in the layout to put each one (NORTH, SOUTH, EAST, WEST, CENTER). By default it's BorderLayout.CENTER if not specified, which is why you only see the last one added.
I'm just beginning on making a GUI for a lwjgl engine. I have a canvas on the left hand side and I want to have a JPanel on the right for previewing textures. However as you can see, the image is barely visible. I've tried different Borderlayouts, trying to resize etc.. However I think I'm just doing something fundamentally wrong.
My panel class
public class Panel extends JPanel {
BufferedImage image;
public Panel(){
try {
image = ImageIO.read(new
File("C:/Users/tom/Desktop/raj/Jtest/src/AWT/house.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void paintComponent(Graphics g){
// super.paint(g);
g.drawImage(image,0, 0, null);
}
and here is how I'm trying to implement it.
public static void main(String[] args)
{
Panel panel = new Panel();
UIManager.setLookAndFeel("com.jtattoo.plaf.hifi.HiFiLookAndFeel");
JFrame frame = new JFrame("World Editor");
frame.setLayout(new BorderLayout());
final Canvas canvas = new Canvas();
button1.setSize(100, 100);
button1.setLocation(600, 10);
button1.setText("Test");
canvas.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e)
{ canvas.setSize(800, 600);
newCanvasSize.set(canvas.getSize());
}
});
frame.setBackground(Color.black);
frame.add(button1);
frame.add(panel,BorderLayout.EAST);
frame.getContentPane().add(canvas,BorderLayout.CENTER);
try {
Display.setParent(canvas);
Display.setVSyncEnabled(true);
frame.setPreferredSize(new Dimension(1600, 1400));
frame.setMinimumSize(new Dimension(800, 600));
frame.pack();
frame.setVisible(true);
Display.create();
etc...
the setup should of been like this http://i.imgur.com/Zitizdx.png
ePanel panel = new ePanel(0, 0);
UIManager.setLookAndFeel("com.jtattoo.plaf.hifi.HiFiLookAndFeel");
JFrame frame = new JFrame("World Editor");
frame.setLayout(new BorderLayout());
canvas = new Canvas();
canvas.setSize(1200, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
button1.setSize(100, 100);
button1.setText("TEST");
frame.add(button1);
frame.add(canvas,BorderLayout.WEST);
frame.add(panel, BorderLayout.CENTER);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
Do you already tried to set the image for a background label and resize it? Something like this:
http://www.java2s.com/Code/Java/Swing-JFC/Labelbackgroundiconalign.htm
Don't use a Canvas. That is an AWT class and you should not mix AWT components in a Swing application. I'm not sure what the point of the Canvas is, but you should probably be using a JPanel.
Don't call you class "Panel". There is an AWT class with that name already. Class names should be more descriptive.
In fact, don't even create a custom class. Just use a JLabel with an ImageIcon to display the image. I'm guessing the problem is that you didn't override the getPreferredSize() method of the "Panel" class so the size is (10, 10) by default which is the size the panel will have because you are using a FlowLayout. So either use a JLabel (easy solution) or implement the getPreferredSize() method to reflect the size of the image.
Set a GridLayout to the JFrame new GridLayout(0, 2)
http://docs.oracle.com/javase/tutorial/uiswing/layout/grid.html
That way, the JFrame has left and right side. Then create and add two JPanels to the Jframe. Do not forget resize the panels and the frame.
After that, create a label, set to it an icon image, resize it and add it to the right panel.
I have a very simple java swing application, I have a canvas class extended from JPanel
public class Canvas extends JPanel
{
private void doDrawing(Graphics g)
{
Graphics2D g2d = (Graphics2D) g;
g2d.drawString("Java 2D", 50, 50);
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
doDrawing(g);
}
}
And then I have my main class
public class SwingCounter extends JFrame {
private JTextField tfCount; // Use Swing's JTextField instead of AWT's TextField
private int count = 0;
public SwingCounter () {
Container cp = getContentPane();
cp.setLayout(new FlowLayout());
cp.add(new JLabel("Counter"));
tfCount = new JTextField("0", 10);
tfCount.setEditable(false);
cp.add(tfCount);
JButton btnCount = new JButton("Count");
cp.add(btnCount);
Canvas canvas = new Canvas();
canvas.setSize(150, 150);
cp.add(canvas);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Exit program if close-window button clicked
setTitle("Swing Counter"); // "this" JFrame sets title
setSize(300, 100); // "this" JFrame sets initial size
setVisible(true); // "this" JFrame shows
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new SwingCounter(); // Let the constructor do the job
}
});
}
}
It is basically code from a tutorial, apart from the JPanel. Everything shows fine, the JPanel/Canvas doesn't. What is missing?
You are adding your Canvas class to a panel which uses a FlowLayout. The FlowLayout respects the preferred size of all components. Your component has a preferred size of (0, 0) so there is nothing to paint.
You need to override the getPreferredSize() method of your Canvas class to return an appropriate Dimension for your panel.
Read the section from the Swing tutorial on Custom Painting for more information and a working example that does implement the getPreferredSize() method.
Also, don't call your class Canvas, since that is already an AWT component and is confusing. Use a more descriptive name.
I have a custom JPanel. The only thing that is in it, is a drawing of a rectangle, using the drawRect method of the Graphics object. The JPanel is always in a very specific square size, refuses to get any bigger or smaller. Tried overriding the getPreferredSize() method, didn't work.
Tried setting different layout managers for this custom JPanel, and also tried every layout manager for the JPanel that hosts this JPanel. Still, the size of the custom JPanel stays the same.
As I said, the custom JPanel has no components in it, only a drawing of a rectangle.
Any ideas?
Without knowing more about what you're trying to achieve:
As far as your containing panel, you need to know which layout managers respect preferred sizes and which ones don't
Grid Flow Border Box GridBag
Respect PreferredSize NO YES NO YES YES
That being said, if you wrap the painted JPanel in a JPanel with one of the "NOs", the painted JPanel shoud stretch with the resizing of the frame.
Also if you want the drawn rectangle to stretch along with its JPanel, then you need to remember to draw the rectangle with getWidth() and getHeight() of the JPanel and not use hard coded values.
Here is an example using BorderLayout as the containing panel's layout, and making use of getWidth() and getHeight() when performing the painting.
import java.awt.*;
import javax.swing.*;
public class StretchRect {
public StretchRect() {
JPanel panel = new JPanel(new BorderLayout());
panel.add(new RectanglePanel());
JFrame frame = new JFrame();
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public class RectanglePanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillRect( (int)(getWidth() * 0.1), (int)(getHeight() * 0.1),
(int)(getWidth() * 0.8), (int)(getHeight() * 0.8) );
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new StretchRect();
}
});
}
}
I'm currently trying to draw shapes on a JPanel, which is within another JPanel, within a JFrame.
I've searched Google and Youtube and found out how to draw shapes within a JFrame that has one panel, but have found nothing which can help me with what I'm doing. (maybe I'm not seeing something).
Code I've seen so far:
public class GameScreen
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
public static void main(String[] args)
{
GameScreen gs = new GameScreen();
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(gs);
}
This is all good for when I'm dealing with just one panel, but I wanna display shapes on a panel which is within the 1'st panel I've created.
Add a JPanel to the JFrame in the same way as you're doing now, but do it with your own subclass of JPanel.
class MyPanel extends JPanel {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400,400); // As suggested by camickr
}
}
You can add this to a JPanel which sits within the JFrame
public static void main(String[] args)
{
MyPanel mp = new MyPanel();
JPanel jp = new JPanel();
jp.add(mp);
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(jp);
}
This can work for components within components, if you add them as children components. The key is to extend the component and override the methods you wish to change.
This is all good for when I'm dealing with just one panel,
The code you posted works fine because a frame uses a BorderLayout. So, when you add your panel to the frame is will increase in size and your custom painting will be seen.
I wanna display shapes on a panel which is within the 1'st panel I've created.
When you create a panel it uses a FlowLayout by default. When you add a custom painting panel to that panel it will be displayed at its preferred size, which will be (0, 0) since you didn't specify the preferred size.
On the panels that do custom painting you also need to implement the getPreferredSize() method so the layout manager knows how to arrange the panels. For example:
public Dimension getPreferredSize()
{
return new Dimension(200, 200);
}