I am trying to mess around with some graphics in java, however i can't get it to work. The JFrame comes up with the button i created, but the JFrame is just gray with no red line that i want it to draw.
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Shapes extends JFrame implements ActionListener{
JButton button = new JButton("click");
public Shapes() {
setVisible(true);
setSize(500, 500);
button.addActionListener(this);
button.setSize(20, 20);
setLayout(new FlowLayout());
add(button);
repaint();
}
public static void main(String[] args){
Shapes s = new Shapes();
}
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.red);
g2.drawLine(5, 10, 10, 20);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == button){
repaint();
}
}
}
Two things:
1). You don't really want to do custom painting on a top-level container such as a JFrame. Instead you want to use a JPanel
class Panel extends JPanel
{
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.red);
g2.drawLine(5, 10, 10, 20);
}
}
And add it to your JFrame: add(new Panel()); (Or create an object if you want).
2). setVisible(true); should be the very last thing that you do while setting up your window. So change your constructor:
public Shapes() {
setSize(500, 500);
button.addActionListener(this);
button.setSize(20, 20);
setLayout(new FlowLayout());
add(button);
add(new Panel()) // added from part 1
repaint();
setVisible(true);
}
For more information go through the "performing custom painting tutorials."
Related
So I am new in java graphics and I am creating a program that will show a rectangle. But when I run my program it only show like a small box and not the rectangle. I don't really know why it is happening.
Here is my code:
import javax.swing.*;
public class GraphicsEditor{
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
Rectangle rectangle = new Rectangle();
frame.setSize(1280, 720);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(panel);
panel.add(rectangle);
}
}
This is my rectangle class:
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
public class Rectangle extends JPanel implements Shape {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g2D.fillRect(0, 0, 200, 130);
}
}
This is my shape interface:
import java.awt.*;
public interface Shape {
void paintComponent(Graphics g);
}
Here, try this
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;
public class GraphicsEditor {
public static void main(String[] args) {
JFrame frame = new JFrame();
Rectangle rectangle = new Rectangle();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(rectangle);
frame.pack();
// center frame on screen
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class Rectangle extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g2D.fillRect(0, 0, 200, 130);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
}
A couple of things.
you don't need the interface.
unlike components, just painting a picture doesn't affect the layout manager, so the panel will be reduced to it's default size with out regard to any painting.
so you need to override getPreferredSize() in your JPanel.
As the comments said, you should set the preferred size of both your panel and rectangle to your desired size, and then pack the frame, like:
panel.setPreferredSize(new Dimension(500,500));
rectangle.setPreferredSize(new Dimension(500,500));
frame.pack();
Otherwise your LayoutManager (when not specified it defaults to FlowLayout) will handle your rectangle the way it wants. So another way would be learning about Layout Managers, and using your desired one.
As a side note, I would like to make some suggestions to your code. Remember, Swing is not thread safe, so place your code inside an invokeLater() call, such as:
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
Rectangle rectangle = new Rectangle();
frame.setSize(1280, 720);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setPreferredSize(new Dimension(500,500));
rectangle.setPreferredSize(new Dimension(500,500));
frame.add(panel);
panel.add(rectangle);
frame.pack();
frame.setVisible(true);
}
});
Also, calling frame.setVisible(true) should be called after adding your components.
I want to draw circle and align it to center, but when I am calling repaint() nothing happens. I tried almost everything, I have changed layouts, alignments, but always the same. This is my code:
public class Frame extends JFrame {
JButton button,dugme;
JLabel lab;
public Frame(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(480,320);
setResizable(false);
setLocationRelativeTo(null);
setLayout(new FlowLayout());
setVisible(true);
button = new JButton("Klikni me");
button.setSize(75,75);
add(button);
button.setHorizontalAlignment(SwingConstants.RIGHT);
dugme= new JButton("Klikni opet");
dugme.setSize(75,75);
add(dugme);
dugme.setHorizontalAlignment(SwingConstants.LEFT);
lab = new JLabel("Ovde je tekst koji se menja");
add(lab);
lab.setHorizontalAlignment(SwingConstants.CENTER);
Handler handler = new Handler();
Handler1 handler1= new Handler1();
repaint();
button.addActionListener(handler);
dugme.addActionListener(handler1);
}
public void paintComponent(Graphics g){
super.paintComponents(g);
g.fillOval(30, 30, 60, 75);
}
public class Handler implements ActionListener{
public void actionPerformed(ActionEvent e){
repaint();
lab.setText("New text");
}
}
public class Handler1 implements ActionListener{
public void actionPerformed(ActionEvent e){
lab.setText("Same text again ");
repaint();
}
}
}
public void paintComponent(Graphics g){
super.paintComponents(g);
Breaks the paint chain, it should be:
public void paintComponent(Graphics g){
super.paintComponent(g); // no S in method name..
I am using a JFrame and a pane and trying to draw a simple square.
My painting is not showing up. I made I set the color to black so it should be visible.
Code:
package W2;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import javax.swing.*;
public class W2 {
JFrame frame = new JFrame("W2");
public W2(){
Container pane = new Container();
frame.setContentPane(pane);
frame.setSize(750,500);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
}
public void paint(Graphics g){
g.setColor(Color.BLACK);
g.fillRect(50, 50, 50, 50);
}
public static void main(String args[]){
new W2();
}
}
The paint method won't be called because it's not part of a object that can be painted.
See Performing Custom Painting for details about how painting is done in Swing
For example...
frame.setContentPane(new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLACK);
g.fillRect(50, 50, 50, 50);
}
});
I tried to implement a simple GUI application,having a class extend JPanel and then adding it to a frame and adding a button,but nothing happens when I click on the button.What is wrong?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class dup extends JPanel {
public void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.green);
g2d.fillRect(0, 0, this.WIDTH, this.HEIGHT);
System.out.println("inside paint component class");
}
}
public class drawing implements ActionListener {
JFrame frame;
dup d1;
public static void main(String args[]) {
drawing d2 = new drawing();
d2.go();
}
public void go() {
frame = new JFrame();
JButton button = new JButton("click me");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
d1 = new dup();
button.addActionListener(this);
frame.getContentPane().add(BorderLayout.WEST, button);
frame.getContentPane().add(BorderLayout.CENTER, d1);
frame.setSize(300, 300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent ae) {
frame.repaint();
}
}
What is wrong with this?
Width and height is wrong. It should be
g2d.fillRect(0, 0, this.getWidth(), this.getHeight());
You were using constants from ImageObserver class instead of width and height properties of the component.
I want to create a wall with a blue line outline and black filling. I have only a blue wall now and I tried a couple of the Graphics methods but wasn't working.
public void paint(Graphics g) {
g.setColor(Color.blue);
g.fillRect(x, y, size, size);
}
Use Graphics#drawRect to draw the outline: -
g.setColor(Color.black);
g.fillRect(x, y, size, size);
g.setColor(Color.blue);
g.drawRect(x, y, size, size);
First, override paintComponent, not paint. Second, there's no need to re-invent the wheel like that. Instead, use an existing Swing component (e.g. JPanel),
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Main
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.add(getWallComponent());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private static JPanel getWallComponent()
{
JPanel panel = new JPanel();
panel.setBackground(Color.black);
panel.setBorder(BorderFactory.createLineBorder(Color.blue, 5));
panel.setPreferredSize(new Dimension(200, 200)); // for demo purposes only
return panel;
}
}
Just paint another rectangle over the blue one, smaller than the blue one, like below
public void paint(Graphics g) {
g.setColor(Color.blue);
g.fillRect(x, y, size, size);
g.setColor(Color.black);
g.fillRect(x-width/2,y-width/x,size-width,size-with);
}
package painting;
import java.awt.*;
import javax.swing.*;
public class RectangleOutline extends JPanel {
int x = 100;
int y = 200;
public void paintComponent(Graphics g) {
super.paintComponent(g);
outline(g);
}
public void outline(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(new Color(255, 0, 0));
g2.fillRect(x, y, 30, 30);
g2.setStroke(new BasicStroke(5));
g2.setColor(new Color(0, 0, 0));
g2.drawRect(x, y, 30, 30);
}
public static void main(String[] args){
JFrame f = new JFrame();
RectangleOutline graphics = new RectangleOutline();
f.add(graphics);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
f.setSize(400, 400);
}
}