Thread: Java animation code

Hello I am new to the forum and hope you can help me I put my code and then the errors I receive thank you so much

import javax.swing.*;
import java.awt.*;
import javax.swing.Timer;
public class Square extends JFrame {
public Star() {
setSize(1000,1000);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args){
new Star();
}
}
class Doit extends JPanel {
Timer timer;
int x, y;
public Doit() {
setBackground(Color.RED);
x = 30;
y = 70;
timer = new Timer(25, this);
timer.start();
}
public void paint(Graphics g) {
g.drawRect(x, y, 500, 500);
g.fillRect(x, y, 500, 500);
}
while(x<1000) {
x++;
repaint();
}
}

Star.java:5: error: invalid method declaration; return type required
public Star() {
       ^
Star.java:29: error: illegal start of type
while(x<1000) {
^
Star.java:29: error: illegal start of type
while(x<1000) {
        ^
Star.java:29: error: <identifier> expected
while(x<1000) {
            ^
Star.java:29: error: ')' expected
while(x<1000) {
             ^
Star.java:29: error: ';' expected
while(x<1000) {
               ^
Star.java:30: error: illegal start of type
x++;
 ^
Star.java:30: error: <identifier> expected
x++;
   ^
Star.java:30: error: ';' expected
x++;
    ^
Star.java:31: error: illegal start of type
repaint();
       ^
Star.java:31: error: <identifier> expected
repaint();
        ^
Star.java:33: error: class, interface, or enum expected
}

Originally Posted by Norm

That looks like the syntax for a class's constructor. Is it in a class named: Star?

For the other errors, make sure the statements are inside of a method.

The code is not properly formatted making it hard to read and understand what it does.
Nested statements should be indented 3-4 spaces to show the nesting logic. All statements should NOT start in the first column.

Please Edit the code and fix the formatting.

Hey! I redid the code as you asked, and now I only get one error. Could you help me figure out how to fix this error? Below is the code.

import javax.swing.*;
 
import java.awt.*;
 
import java.awt.event.ActionListener;
 
import javax.swing.Timer;
 
public class Square extends JFrame
{
 
    public Square()
    {
 
        setSize(1000,1000);
 
        setVisible(true);
 
        setResizable(false);
 
        setDefaultCloseOperation(EXIT_ON_CLOSE);
 
 
    }
 
 
    public static void main(String[] args)
    {
 
        new Square();
 
 
    }
 
 
 
}
 
 
class Board extends JPanel
{
 
    Timer timer;
 
    int x, y;
 
    public Board()
    {
 
        setBackground(Color.RED);
 
        x = 30;
 
        y = 70;
 
        timer = new Timer(25, this);
 
        timer.start();
 
 
    }
 
 
    public void paint(Graphics g)
    {
 
        g.drawRect(x, y, 500, 500);
 
        g.fillRect(x, y, 500, 500);
 
        while(x<
        1000)
        {
 
            x++;
 
            repaint();
 
 
        }
 
 
 
    }
 
 
 
 
}

now, I get the error:

Square.java:23: error: constructor Timer in class Timer cannot be applied to given types;
timer = new Timer(25, this);
        ^
  required: int,ActionListener
  found: int,Board
  reason: actual argument Board cannot be converted to ActionListener by method invocation conversion

Originally Posted by Norm

The compiler is saying that Board is not an ActionListener.
Read the API doc for the Timer class to see what data types are required for its constructor.

See the tutorial on how to write an action listener:
How to Write an Action Listener (The Java™ Tutorials > Creating a GUI With JFC/Swing > Writing Event Listeners)

With Swing classes you should override the paintComponent() method, not the paint() method.

I did and it still doesn't work.

It still does not work I made it an action listener

ok here is the code..

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import javax.swing.Timer;
 
public class Square extends JFrame {
	public Square() {
		setSize(1000, 1000);
		setVisible(true);
		setResizable(false);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
	}
 
	public static void main(String[] args) {
		new Square();
	}
}
 
class Board implements ActionListener {
	Timer timer;
	int x, y;
 
	public Board() {
		setBackground(Color.RED);
		x = 30;
		y = 70;
		timer = new Timer(25, this);
		timer.start();
	}
 
	public void paint(Graphics g) {
		g.drawRect(x, y, 500, 500);
		g.fillRect(x, y, 500, 500);
		while (x < 1000) {
			x++;
			repaint();
		}
	}
 
}

the errors are:





Square.java:19: error: Board is not abstract and does not override abstract method actionPerformed(ActionEvent) in ActionListener
class Board implements ActionListener {
^
Square.java:24: error: cannot find symbol
setBackground(Color.RED);
^
symbol: method setBackground(Color)
location: class Board
Square.java:36: error: cannot find symbol
repaint();
^
symbol: method repaint()
location: class Board

Where should I define the setBackground and repaint methods?

Ok. I know i'm not supposed to really explicitly ask, but do you think you could make my code work? I know you're one of the best on the site and could do it in an instance(no pun intended ). Because I have been trying all day and am getting really frustrated is the only reason i'm asking thank you norm

Ok, my new code is:

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import javax.swing.Timer;
 
public class Square extends JFrame {
	public Square() {
		setSize(1000, 1000);
		setVisible(true);
		setResizable(false);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
	}
 
	public static void main(String[] args) {
		new Square();
	}
}
 
class Board implements ActionListener {
	Timer timer;
	int x, y;
 
	public Board() {
		setBackground(Color.RED);
		x = 30;
		y = 70;
		timer = new Timer(25, this);
		timer.start();
	}
 
	public void paint(Graphics g) {
		g.drawRect(x, y, 500, 500);
		g.fillRect(x, y, 500, 500);
		while (x < 1000) {
			x++;
		}
                g.repaint();
 
	}
 
}

now I get three errors;

 
Square.java:19: error: Board is not abstract and does not override abstract method actionPerformed(ActionEvent) in ActionListener
class Board implements ActionListener {
^
Square.java:24: error: cannot find symbol
		setBackground(Color.RED);
		^
  symbol:   method setBackground(Color)
  location: class Board
Square.java:37: error: cannot find symbol
                g.repaint();
                 ^
  symbol:   method repaint()
  location: variable g of type Graphics
3 errors

I can't figure it out could you fix it?