what's the easiest way to have a drawing in a JPanel that resizes whenever the user resizes the JFrame?
I know that I can auto resize the panel with a BorderLayout but the drawings are not resized in this case. I am new to java and GUI programming and there are probably numerous solutions.
please give me a hint into the right direction to make e.g. the rectangle in
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.*;
public class DrawRect extends JPanel {
#Override
protected void paintComponent(Graphics g) {
g.drawRect(20, 20, 100, 100);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
DrawRect panel = new DrawRect();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(200, 200));
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
}
}
auto-resizing whenever the frame is resized.
Provide positions and sizes as a proportion of the width and height of the panel. Whenever the panel is resized, the rendering engine will schedule a call to the paintComponent() method and the rectangle will be drawn proportionally. E.G.
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.*;
public class DrawRect extends JPanel {
#Override
protected void paintComponent(Graphics g) {
int w = getWidth();
int h = getHeight();
g.drawRect(w/10, h/10, w/2, h/2);
}
/* A custom component should give the layout manager hints as to
its preferred size. */
#Override
public Dimension getPreferredSize() {
return new Dimension(200,200);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
DrawRect panel = new DrawRect();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
}
}
frame.getContentPane().setLayout(new BorderLayout());
Insert the line before you add the component to the GUI.
You should study layoutmanagers, since it is a unique concept in Java.
Related
I'm trying to create a super simple component, and it's not appearing.
Component class:
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JComponent;
public class Player extends JComponent{
public Player()
{
}
public void paint(Graphics g)
{
g.setColor(Color.green);
g.fillRect(40,40,150,150);
}
}
Panel Class im adding it to:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.JPanel;
public class Game extends JPanel{
public Game()
{
this.setBackground(Color.yellow);
this.setPreferredSize(new Dimension(500,500));
Player p = new Player();
this.add(p);
}
}
And the JFrame:
import javax.swing.JFrame;
public class Launcher {
public static void main(String[] args) {
JFrame frame = new JFrame("Key Collector Demo");
frame.add(new Game());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
}
}
The only thing showing up is the yellow background.
JFrame and JPanel are working fine; this problem consistently happens to me when building jcomponents. What am I missing?
Any help would be greatly appreciated!
Coordinates that you are using to draw a component are defined in the space of that component.
If you do this:
public void paint(Graphics g)
{
g.setColor(Color.green);
System.out.println(getSize());
g.fillRect(40,40,150,150);
}
You will see that at the moment it is attempted to get drawn its size is 1x1. So drawing it from 40,40 obviously takes it out of the visible area of the component.
Now change the method to:
public void paint(Graphics g)
{
g.setColor(Color.green);
System.out.println(getSize());
setSize(45, 45);
g.fillRect(40,40,150,150);
}
Now you can see small filled rectangle. This is because you forced the size to be 45x45 and now there are 5 pixels to show in the space of the component while the remaining part is still out of the area.
Do not assume the Player panel to have a fixed size.
For a first test your paint method could look like this:
public void paint(Graphics g) {
g.setColor(Color.green);
g.fillRect(0,0,getWidth(),getHeight());
}
The next problem is that the component probably has no size or position. Add a LayoutManager to your panel and add the component:
public Game() {
this.setBackground(Color.yellow);
this.setPreferredSize(new Dimension(500,500));
this.setLayout(new BorderLayout());
Player p = new Player();
this.add(p, BorderLayout.CENTER);
}
With that, your player might take the full space and you see green instead of yellow. Play around with the LayoutManager and the player's preferredSize.
Im trying to add a JScrollpane to my JPanel. The problem is that the scrollpane doesn't recognize that my drawing is outside the frame. So how do I add the JScrollpane correctly?
Main class:
public MainFrame() extends JFrame{
public MainFrame() {
Container container = getContentPane();
container(new BorderLayout());
container.add(new JScrollPane(new Drawing()));
setSize(1280,720);
setVisible(true);
}
Drawing class:
public class Drawing() extends JPanel {
#Override
protected void paintComponent(Graphics g) {
g.drawLine(10, 100, 30000, 10);
}
}
There are a couple of errors in your code, let's step through each of them:
You're extending JFrame, and you should avoid it, see: Extends JFrame vs. creating it inside the program for more information about it. You're actually not changing its behavior so it's not needed to extend it.
For your JScrollPane to show the whole line, you need to change your window's size to be the same size of your line (as shown in this answer by #MadProgrammer).
Related to point 2, avoid the use of setSize(...) and instead override getPreferredSize(): See Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing? for more information
You forgot to call super.paintComponent(...) method in your paintComponent() method.
Related to points 2, 3, you need to call pack() so Swing calculates the best preferred size for your component.
See this example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class LongDraw {
private JFrame frame;
private Drawing drawing;
public static void main(String[] args) {
SwingUtilities.invokeLater(new LongDraw()::createAndShowGui);
}
private void createAndShowGui() {
frame = new JFrame(getClass().getSimpleName());
drawing = new Drawing();
JScrollPane scroll = new JScrollPane(drawing);
frame.add(scroll);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
class Drawing extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.drawLine(10, 100, 3000, 10);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(3000, 500);
}
}
}
Which produces something similar to this:
I am currently still learning Java GUI and stumped on this problem. I just wonder why can't i load it anywhere except on center and how do i load my image anywhere else?
import java.awt.*;
import javax.swing.*;
public class GUI {
public static void main(String[] args) {
GUI gui = new GUI();
gui.go();
}
public void go() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
Player player = new Player();
panel.setBackground(Color.darkGray);
JButton button = new JButton("shock me");
panel.add(button);
frame.getContentPane().add(BorderLayout.EAST, panel);
frame.getContentPane().add(BorderLayout.NORTH, player);
//frame.getContentPane().add(BorderLayout.CENTER, player);
frame.setSize(200,200);
frame.setVisible(true);
}
}
Here's my player class
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.util.Random;
import javax.swing.*;
public class Player extends JPanel{
public void paintComponent(Graphics g) {
Image image = new ImageIcon("Source/hero.jpg").getImage();
g.drawImage(image, 3, 4 , this);
}
}
Player does not override getPreferredSize() to return a value. Since it does not do that, the BorderLayout will not assign it any height in the PAGE_START or PAGE_END constraints, and no width in the LINE_START and LINE_END constraints. The component is being added, it just has no width/height.
The CENTER will stretch both a component's width and height to the available space, that is why it is visible there.
I am trying to put 2 JPanels in borderLayout. Such that, one JPanel will be of size pane1(600,600)and the other one would be pane2(200,600). I am hoping to pack them such that the big one would be on the left and other one would be on right.
I am setting the size of each jpane but it looks like both of them occupy the complete space and kind of overlap on each other.
I am a complete newbie here and have no clue what is going wrong. Any help is appreciated.
JFrame frame = new JFrame("Simple Graph");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
int pane1_width = FRAME_WIDTH-200;//800-200
Pane1 myPlots = new Pane1(graph_panel_size, FRAME_HEIGHT);
frame.add(myPlots);
Pane2 simpleInfo = new Pane2(200,FRAME_HEIGHT);
frame.add(simpleInfo);
frame.pack();
frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
frame.setResizable(false);
frame.setVisible(true);
This is a base frame class. For JPanel
public Pane2(int width,int height){
this.setSize(width,height);
Border blackline = BorderFactory.createTitledBorder("ola");
this.setBorder(blackline);
The other panel also has similar constructor. But both the Jpanels overlap each other and I cant place them separately.
The problem is that you are calling setSize(). When using LayoutManager's (which you should absolutely always do), using setSize/setBounds/setLocation is completely useless.
Additionnaly, calling setPreferredSize()/setMinimumSize/setMaximumSize is not recommended and can be counterproductive.
Either your component have a good reason to have a given size (because you are doing custom painting, for example), then you should override getPreferredSize, or you simply don't have to do anything, and only use an appropriate LayoutManager.
You can also check out the tutorial on LayoutManager of Oracle
See this example with overrides of getPreferredSize():
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestCustomPainting {
private static class MyTriangle extends JPanel {
private final int width;
private final int height;
public MyTriangle(int width, int height) {
this.width = width;
this.height = height;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(width, height);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.GREEN);
g.fillPolygon(new int[] { 0, getWidth(), 0 }, new int[] { 0, 0, getHeight() }, 3);
}
}
protected static void initUI() {
JFrame frame = new JFrame("test");
frame.add(new MyTriangle(200, 45), BorderLayout.EAST);
frame.add(new MyTriangle(85, 600), BorderLayout.WEST);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
initUI();
}
});
}
}
NB: I must admit, there are more interesting to paint :-)
I am trying to paint an image onto a panel, that is contained by a frame.
Let us say I have a 320 x 480 image.
When i try to create a frame with size 320x480 and add the panel into it, I encounter a problem.
In different operating systems, the JFrame of 320x480 is of different sizes due to title bar.
Thus my correct fit image in windows XP will not be properly painted in Windows8 or Ubuntu.
A grey patch is visible because the image was not properly placed.
I tried overriding paint method and using ImageIcon.
Please do offer a solution.
TIA
Code Snippet
CLASS PA CONTENTS
setPreferredSize(new Dimension(500,500));
.
.
JLabel image= new JLabel();
ImageIcon background = new ImageIcon(getClass().getClassLoader().getResource("Flower.jpg"));
image.setBounds(0, 0, 500, 500);
image.setIcon(background);
this.add(image); //where "this" is extending from JPanel
CLASS PB CONTENTS
frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
inserting(frame.getContentPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
private void inserting(Container pane)
{
cardPanel=new JPanel();
CardLayout cards=new CardLayout();
cardPanel.setLayout(cards);
PA home= new PA();
cardPanel.add(home,"homeScreen");
pane.add(cardPanel);
}
Don't call setSize at all, call pack (as VGR stated in his comment). pack will size your JFrame based on size's of component's within it, and gaps between those component's.
Now.. issue you will encounter is that your JFrame will be small at startup. So override getPreferredSize method for your JPanel to return dimensions of your image:
public void getPreferredSize() {
return new Dimension(image.getWidth(), image.getHeight());
}
Now your image will fit perfectly and your application will be fully OS independent.
And also, do not override paint method. Instead, override paintComponent.
Here is a small demo I made in cases like yours:
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class Drawing {
JFrame frame = new JFrame();
public Drawing() {
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(new Panel());
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Drawing();
}
});
}
class Panel extends JPanel {
BufferedImage image = null;
Panel() {
try {
image = ImageIO.read(new File("path-to-your-image"));
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
#Override
public Dimension getPreferredSize() {
// Panel will be sizes based on dimensions of image
return new Dimension(image.getWidth(), image.getHeight());
}
}
}
It seems to be the layout problem. The most obvious solution is to wrap you image panel into another container with proper layout, so your panel will always have the same size.