AWT: Painting buttons

[Fred Wagner]

Hi,

I am trying to find out how I can add buttons to my programme. It is a programme that calculates and paints coordinates. At the moment the variables are constants, but I would like in the end that one will be able to click on the button "m:15" and then the calculations are performed with m=15. Or even better with a textarea where personal numbers can be added.


This is my very first java programme and I have no clue about how to add the buttons. I have posed this question on the AWT/SWING subforum of the java-forums.org already - however nobody has answered yet (excuse the missing of a link to the thread, but the site seems to be offline right now).

  

import java.lang.* ;
import java.awt.*  ;


import javax.swing.* ;


class mj10 extends Frame{
	mj10(){
		add ("Center", new Dumbo());
		setTitle("mambo");
		setSize(900,900);
		setVisible(true);
}	
	public static void main (String [] args) {
		new mj10 ();
		new Frame2();
	}
}
class Dumbo extends Canvas{
	public void paint(Graphics g) {
		
		//* here the calculations and the painting is done, the methods 1-5 are also used in painting, so I removed them too for better readability... **/
		}	
	}	
METHOD1 (used for painting)
		}



METHOD2 (used for painting)
		}
METHOD3 (used for painting)
		}
METHOD4 (used for painting)
		}
METHOD5 (used for painting)
		}


}


class Frame2 extends Frame{
	private Button button1 = new Button( "ok");
	
	public Frame2( String Beschriftung){
		super(Beschriftung);
		setLayout(new FlowLayout());
		add(button1);
	}
	static public void main(String [] args){
		Frame2 f = new Frame2( "Demo");
		f.setSize(234, 123);
		f.show();
	}
//}


  

Above you can see my attempt to create a seperate button class, and then give that out in the frame. It just won't work. (There are so many error messages that I won't post them, but if they are wished-for I will post them)

I really hope somebody will help me out. Thank you in advance.


chappa

[R Johnson]

Your compile problem is Frame2 takes a String Argument in the (). So you can't' just call Frame2().... you have to call Frame2("STRING"); Also I cannot get it to compile with

  METHOD1 (used for painting)   
        }   
  
  
  
METHOD2 (used for painting)   
        }   
METHOD3 (used for painting)   
        }   
METHOD4 (used for painting)   
        }   
METHOD5 (used for painting)   
        }   
  

your Fram2() call on line 19 needs a String argument though

[Fred Wagner]

Hi Mr. Johnson and thank you for your reply,



I have cheated my way around it by using the code of somebody else who had 2 buttons implemented already. My problem now is to figure out how can I make it so that my buttons (and future textareas) will change the value of the variables in the programme?

 /* most of the code was written by "zweibieren" from the java-forums.org/
**/ 



package Test;

import java.awt.*;
import java.awt.event.*;


import javax.swing.*;

public class Success  extends JPanel {

	// the window
	Window winFred;

	// the contents of the window
	JButton eatMeButton, SuccessButton;
	Circle circ;

	final static Dimension BUTTON_SIZE = new Dimension(125,75);
	final static Dimension WINDOW_SIZE = new Dimension(1024,768);
	final static Dimension CIRC_SIZE = new Dimension(900,900);

	public Success() {
		setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));

		// sandwich the buttonBox between two layers of stretchy glue
		Box buttonBox = Box.createHorizontalBox();
		add(Box.createVerticalGlue());
		add(buttonBox);
		add(Box.createVerticalGlue());
		
		eatMeButton = new JButton("eat me");
		eatMeButton.setPreferredSize(BUTTON_SIZE);
		SuccessButton = new JButton("drink me");
		SuccessButton.setPreferredSize(BUTTON_SIZE);
		circ = new Circle();
		circ.setPreferredSize(new Dimension(CIRC_SIZE.height, CIRC_SIZE.height));

		
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(circ);
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(eatMeButton);
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(SuccessButton);
		buttonBox.add(Box.createHorizontalGlue());

	}



	// the circle

	static class Circle extends JPanel {
		

		@Override
		public void paintComponent(Graphics g) {
			g.setColor(Color.red);
			Graphics2D gg = (Graphics2D)g;
		int m = 200000;
		int m1 = 6000;
		int m2 = 8000;
		int b = 900;
		int h = 900;
		
		
		double gamma = 6.67;
		double r = 15;
		double r2 = 20;
		double vx = 0;
		double vx2 = 0;
		double alpha = 0;
		double alpha2 = 0;
		double alpha3 = 0;
		double alpha4 = 0;
		double x = r;
		double x2 = r2;
		double y = 0;
		double y2 = 0;
		double mittelpunktx = b/2;
		double mittelpunkty = h/2;
		double vy = 0.0001 * Math.sqrt(1000 * gamma * m / r);
		double vy2 = 0.0001 * Math.sqrt(1000* gamma * m / r2);
		double tend = 500;
		double t = 0;
		double pi = 4*Math.atan(1);
		double deltat = 0.01;
		double result = 0;
		
		while (t <= tend) {
			
			t = t + deltat;
			r = Math.sqrt(x * x + y * y);
			r2 = Math.sqrt(x2 * x2 + y2 * y2);
			
			double posx = mittelpunktx + x;
			double posy = mittelpunkty + y;
			double posx2 = mittelpunktx + x2;
			double posy2 = mittelpunkty + y2;
			double poswechselx = posx2 - posx;
			double poswechsely = posy2 - posy;
			double rwechselq = poswechselx * poswechselx + poswechsely * poswechsely;
			
			double a = 0.00001 * gamma * ((m / r) / r);
			double a2 = 0.00001 * gamma * ((m / r2) / r2);
			double avon1auf2 = 0.00001 * gamma * (m2 / rwechselq);
			double avon2auf1 = 0.00001 * gamma * (m1 / rwechselq);
			
			alpha = winkel(x,y,alpha);
			alpha2 = winkel(x2, y2, alpha2);
			alpha3 = winkel(poswechselx, poswechsely, alpha3);
			alpha4 = alpha3 + pi;
			
			double ax = a * Math.cos(alpha);
			double ay = a * Math.sin(alpha);
			double ax2 = a2 * Math.cos(alpha2);
			double ay2 = a2 * Math.sin(alpha2);
			double ax3 = avon1auf2 * Math.cos(alpha3);
			double ay3 = avon1auf2 * Math.sin(alpha3);
			double ax4 = avon2auf1 * Math.cos(alpha4);
			double ay4 = avon2auf1 * Math.sin(alpha4);
			
			ax = ax + ax3;
			ay = ay + ay3;
			ax2 = ax2 + ax4;
			ay2 = ay2 + ay4;
			vx = vx - ax * deltat;
			vy = vy - ay * deltat;
			x = x + vx * deltat;
			y = y + vy * deltat;
			vx2 = vx2 - ax2 * deltat;
			vy2 = vy2 - ay2 * deltat;
			x2 = x2 + vx2 * deltat;
			y2 = y2 + vy2 * deltat;
			
			double finalx = skalierenx(posx);
			double finaly = skaliereny(posy);
			double finalx2 = skalierenx2(posx2);
			double finaly2 = skaliereny2(posy2);
			double finalmittelpunktx = skalierenx(mittelpunktx);
			double finalmittelpunkty = skaliereny(mittelpunkty);
			
			
			g.setColor(Color.blue);
			g.drawLine((int)(finalx),(int)(finaly),(int)(finalx),(int)(finaly));
			g.setColor(Color.red);
			g.drawLine((int)(finalx2),(int)(finaly2),(int)(finalx2),(int)(finaly2));
			g.drawLine((int)(finalmittelpunktx),(int)(finalmittelpunkty),(int)(finalmittelpunktx),(int)(finalmittelpunkty));
			}
		}
public double winkel(double xposition, double yposition, double result){
	result = Math.atan(yposition / xposition);
	double pi = 4*Math.atan(1);
	if ((xposition < 0) && (yposition < 0)) {
		result = result + pi;
	}
	if ((xposition < 0 ) && (yposition > 0)){
		result = result + pi;
	}
	if ((xposition > 0) && (yposition <0)) {
		result = result + 2*pi;
	}
	return result;
		}


public double skalierenx(double posx){
	double minPointX = 508.0;
	double maxPointX = 366.594;
	double screenX = (posx - minPointX) * getWidth() / (maxPointX - minPointX);
	
	return screenX;
		}
public double skaliereny(double posy){
	double minPointY = 497.66;
	double maxPointY = 337.468;
	double screenY = (posy - minPointY) * getWidth() / (maxPointY - minPointY);
	
	return screenY;
		}
public double skalierenx2(double posx2){
	double minPointX2 = 508.0;
	double maxPointX2 = 366.594;
	double screenX2 = (posx2 - minPointX2) * getWidth() / (maxPointX2 - minPointX2);
	
	return screenX2;
		}
public double skaliereny2(double posy2){
	double minPointY2 = 497.66;
	double maxPointY2 = 337.468;
	double screenY2 = (posy2 - minPointY2) * getWidth() / (maxPointY2 - minPointY2);
	
	return screenY2;
		}		
	}

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Success");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JComponent newContentPane = new Success();
        frame.setContentPane(newContentPane);

		frame.setPreferredSize(WINDOW_SIZE);
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}
   

If you run this you will see 2 buttons and something painting. My intention is now that I can change the variables via a button (and later also a textarea). How do I do that?


Any help is greatly appreciated.


Thanks.


Chippa


PS: this is the link which leads to the thread in the other forum, for those who are interested : Link to the other Thread (other forum/website!)

[R Johnson]

This is just some code to show an example of how a button works. You must add an action/selection listener to the button and then define what happens in that action. It can be anonymous which basically means it's declared when added and has no name value to reconstruct or can be defined as a class that implements the action and then the class can be called into your project like any other class and used with a defined variable. Here's an example simple and sweet.

  import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Ship  extends JPanel {
    JButton jb1,jb2;
    JLabel jl1;
    ActionListener al=new myButtonListener();
    Ship(){
        jb1=new JButton("Open");
        jb2=new JButton("Close");
        jb1.addActionListener(al);
        jb2.addActionListener(al);
        
        jl1=new JLabel("hello");
        setLayout(new FlowLayout());
        add(jl1);
        add(jb1);
        add(jb2);

    }
    public static void main(String[] args){
    JFrame jf=new JFrame();
    JPanel jp=new Ship();
    jf.setPreferredSize(new Dimension(100,100));
    jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    jf.add(jp);
    jf.pack();
    jf.setVisible(true);
}
class myButtonListener implements  ActionListener{
    public void actionPerformed(ActionEvent ae){
        jl1.setText(((JButton)ae.getSource()).getText());
        
    }
}
}  

[Fred Wagner]

Thank you again Mr. Johnson,


I have found the way to make the button print out "Hi" on pressing. However I still can't figure out how I can make it "erase" my old variable (f.e. m1) and use the one which the button is labelled with. (F.e. the button says m1 = 1500 and then the calculations are done with 1500 instead of the preset 6000)

Also is there a function that will just "clear" my current painting, so that it can be performed with the new variables instead of the default ones?

The current code looks like this:

/* most of the code was written by "zweibieren" from the java-forums.org/
**/ 
/*************************************************
Zeit in 10^6 s
Massen in 10^24 kg
Distanzen in 10^10m
**************************************************/



package Test;

import java.awt.*;
import java.awt.event.*;


import javax.swing.*;

public class Success  extends JPanel {

	// the contents of the window
	JButton eatMeButton, drinkmeButton;
	Circle circ;
	ActionListener al = new myButtonListener();
	
	final static Dimension BUTTON_SIZE = new Dimension(125,75);
	final static Dimension WINDOW_SIZE = new Dimension(1024,768);
	final static Dimension CIRC_SIZE = new Dimension(900,900);

	public Success() {
		setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));

		// sandwich the buttonBox between two layers of stretchy glue
		Box buttonBox = Box.createHorizontalBox();
		add(Box.createVerticalGlue());
		add(buttonBox);
		add(Box.createVerticalGlue());
		
		eatMeButton = new JButton("m1=1500");
		eatMeButton.addActionListener(al);
		eatMeButton.setPreferredSize(BUTTON_SIZE);
		drinkmeButton = new JButton("drink me");
		drinkmeButton.setPreferredSize(BUTTON_SIZE);
		circ = new Circle();
		circ.setPreferredSize(new Dimension(CIRC_SIZE.height, CIRC_SIZE.height));

		
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(circ);
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(eatMeButton);
		buttonBox.add(Box.createHorizontalGlue());
		buttonBox.add(drinkmeButton);
		buttonBox.add(Box.createHorizontalGlue());

	}



	// the circle

	static class Circle extends JPanel {
		

		@Override
		public void paintComponent(Graphics g) {
			g.setColor(Color.red);
			Graphics2D gg = (Graphics2D)g;
		int m = 200000;
		int m1 = 6000;
		int m2 = 8000;
		int b = 900;
		int h = 900;
		
		
		double gamma = 6.67;
		double r = 15;
		double r2 = 20;
		double vx = 0;
		double vx2 = 0;
		double alpha = 0;
		double alpha2 = 0;
		double alpha3 = 0;
		double alpha4 = 0;
		double x = r;
		double x2 = r2;
		double y = 0;
		double y2 = 0;
		double mittelpunktx = b/2;
		double mittelpunkty = h/2;
		double vy = 0.0001 * Math.sqrt(1000 * gamma * m / r);
		double vy2 = 0.0001 * Math.sqrt(1000* gamma * m / r2);
		double tend = 500;
		double t = 0;
		double pi = 4*Math.atan(1);
		double deltat = 0.01;
		double result = 0;
		
		while (t <= tend) {
			
			t = t + deltat;
			r = Math.sqrt(x * x + y * y);
			r2 = Math.sqrt(x2 * x2 + y2 * y2);
			
			double posx = mittelpunktx + x;
			double posy = mittelpunkty + y;
			double posx2 = mittelpunktx + x2;
			double posy2 = mittelpunkty + y2;
			double poswechselx = posx2 - posx;
			double poswechsely = posy2 - posy;
			double rwechselq = poswechselx * poswechselx + poswechsely * poswechsely;
			
			double a = 0.00001 * gamma * ((m / r) / r);
			double a2 = 0.00001 * gamma * ((m / r2) / r2);
			double avon1auf2 = 0.00001 * gamma * (m2 / rwechselq);
			double avon2auf1 = 0.00001 * gamma * (m1 / rwechselq);
			
			alpha = winkel(x,y,alpha);
			alpha2 = winkel(x2, y2, alpha2);
			alpha3 = winkel(poswechselx, poswechsely, alpha3);
			alpha4 = alpha3 + pi;
			
			double ax = a * Math.cos(alpha);
			double ay = a * Math.sin(alpha);
			double ax2 = a2 * Math.cos(alpha2);
			double ay2 = a2 * Math.sin(alpha2);
			double ax3 = avon1auf2 * Math.cos(alpha3);
			double ay3 = avon1auf2 * Math.sin(alpha3);
			double ax4 = avon2auf1 * Math.cos(alpha4);
			double ay4 = avon2auf1 * Math.sin(alpha4);
			
			ax = ax + ax3;
			ay = ay + ay3;
			ax2 = ax2 + ax4;
			ay2 = ay2 + ay4;
			vx = vx - ax * deltat;
			vy = vy - ay * deltat;
			x = x + vx * deltat;
			y = y + vy * deltat;
			vx2 = vx2 - ax2 * deltat;
			vy2 = vy2 - ay2 * deltat;
			x2 = x2 + vx2 * deltat;
			y2 = y2 + vy2 * deltat;
			
			double finalx = skalierenx(posx);
			double finaly = skaliereny(posy);
			double finalx2 = skalierenx2(posx2);
			double finaly2 = skaliereny2(posy2);
			double finalmittelpunktx = skalierenx(mittelpunktx);
			double finalmittelpunkty = skaliereny(mittelpunkty);
			
			
			g.setColor(Color.blue);
			g.drawLine((int)(finalx),(int)(finaly),(int)(finalx),(int)(finaly));
			g.setColor(Color.red);
			g.drawLine((int)(finalx2),(int)(finaly2),(int)(finalx2),(int)(finaly2));
			g.drawLine((int)(finalmittelpunktx),(int)(finalmittelpunkty),(int)(finalmittelpunktx),(int)(finalmittelpunkty));
		//	g.drawOval((int)(finalx),(int)(finaly),);
			}
		}
public double winkel(double xposition, double yposition, double result){
	result = Math.atan(yposition / xposition);
	double pi = 4*Math.atan(1);
	if ((xposition < 0) && (yposition < 0)) {
		result = result + pi;
	}
	if ((xposition < 0 ) && (yposition > 0)){
		result = result + pi;
	}
	if ((xposition > 0) && (yposition <0)) {
		result = result + 2*pi;
	}
	return result;
		}


public double skalierenx(double posx){
	double minPointX = 508.0;
	double maxPointX = 366.594;
	double screenX = (posx - minPointX) * getWidth() / (maxPointX - minPointX);
	
	return screenX;
		}
public double skaliereny(double posy){
	double minPointY = 497.66;
	double maxPointY = 337.468;
	double screenY = (posy - minPointY) * getWidth() / (maxPointY - minPointY);
	
	return screenY;
		}
public double skalierenx2(double posx2){
	double minPointX2 = 508.0;
	double maxPointX2 = 366.594;
	double screenX2 = (posx2 - minPointX2) * getWidth() / (maxPointX2 - minPointX2);
	
	return screenX2;
		}
public double skaliereny2(double posy2){
	double minPointY2 = 497.66;
	double maxPointY2 = 337.468;
	double screenY2 = (posy2 - minPointY2) * getWidth() / (maxPointY2 - minPointY2);
	
	return screenY2;
		}		
	}

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Success");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JComponent newContentPane = new Success();
        frame.setContentPane(newContentPane);

		frame.setPreferredSize(WINDOW_SIZE);
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
class myButtonListener implements ActionListener{
	public void actionPerformed(ActionEvent ae){
	//	m1 = 1500;
	System.out.println("hi");
		}
	}

}
    

Help is again greatly appreciated.


Thank you


chippa

[R Johnson]

If you want to change a variable like

   m1 = 6000  

then you need to declare it as a class/instance variable. Basically outside the method of paintComponent.

   static class Circle extends JPanel {   
           int m1 = 6000;  //HERE!
  
        @Override  
        public void paintComponent(Graphics g) {   
            g.setColor(Color.red);   
            Graphics2D gg = (Graphics2D)g;   
        int m = 200000;   
       //  int m1 = 6000;   Not Here!
        int m2 = 8000;   
        int b = 900;   
        int h = 900;    

This should allow you to change m1 just by calling it.

    class myButtonListener implements ActionListener{   
    public void actionPerformed(ActionEvent ae){   
      m1 = 1500;   //Should work now
    System.out.println("hi");   
        }   
    }   

[Fred Wagner]

I changed my code as you showed, but now I get this error message:

 Success.java:123: non-static variable m1 cannot be referenced from a static context			double avon2auf1 = 0.00001 * gamma * (m1 / rwechselq);			                                      ^1 error   

[R Johnson]

I was hoping to wait for someone with more experience to comment mainly because of your static keyword before the Circle class. Also I'm self taught and by no means a java expert. However I can "make" things work. So as my intentions might be pure my programming might not and I was hoping not to pass on any bad habits but here's how I'd make a quick fix. First I want to explain why it can't access the m1 variable. There is no reference to it. The class a() has no idea where m1 is coming from because it has not been declared. Because the Circle class is static I suspect, but have not tested, that if you do call the Circle class and change m1 you will change it or all Circles however you will be unable to repaint the one residing in your JFrame so you need to point to the Circle that your displaying in your JFrame. Currently your code Circle circ is Empty/Null so you will have to call new Circle() before you can reference the object circ. Then you need to make a parameter for myButtonListener(Circle) so that you can pass that exact Circle to the class and alter it's attributes. After that it compiles and works fine for me.

 import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Success  extends JPanel {

    // the contents of the window
    JButton eatMeButton, drinkmeButton;
    Circle circ=new Circle();
    ActionListener al = new myButtonListener(circ);

    final static Dimension BUTTON_SIZE = new Dimension(125,75);
    final static Dimension WINDOW_SIZE = new Dimension(1024,768);
    final static Dimension CIRC_SIZE = new Dimension(900,900);

    public Success() {
        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));

        // sandwich the buttonBox between two layers of stretchy glue
        Box buttonBox = Box.createHorizontalBox();
        add(Box.createVerticalGlue());
        add(buttonBox);
        add(Box.createVerticalGlue());

        eatMeButton = new JButton("m1=1500");
        eatMeButton.addActionListener(al);
        eatMeButton.setPreferredSize(BUTTON_SIZE);
        drinkmeButton = new JButton("drink me");
        drinkmeButton.setPreferredSize(BUTTON_SIZE);
       
        circ.setPreferredSize(new Dimension(CIRC_SIZE.height, CIRC_SIZE.height));


        buttonBox.add(Box.createHorizontalGlue());
        buttonBox.add(circ);
        buttonBox.add(Box.createHorizontalGlue());
        buttonBox.add(eatMeButton);
        buttonBox.add(Box.createHorizontalGlue());
        buttonBox.add(drinkmeButton);
        buttonBox.add(Box.createHorizontalGlue());

    }



    // the circle

     static class Circle extends JPanel {

        int m1=6000;
        @Override
        public void paintComponent(Graphics g) {
            g.clearRect(0, 0, this.getWidth(), this.getHeight());
            g.setColor(Color.red);
            Graphics2D gg = (Graphics2D)g;
        int m = 200000;
        //int m1 = 6000;
        int m2 = 8000;
        int b = 900;
        int h = 900;


        double gamma = 6.67;
        double r = 15;
        double r2 = 20;
        double vx = 0;
        double vx2 = 0;
        double alpha = 0;
        double alpha2 = 0;
        double alpha3 = 0;
        double alpha4 = 0;
        double x = r;
        double x2 = r2;
        double y = 0;
        double y2 = 0;
        double mittelpunktx = b/2;
        double mittelpunkty = h/2;
        double vy = 0.0001 * Math.sqrt(1000 * gamma * m / r);
        double vy2 = 0.0001 * Math.sqrt(1000* gamma * m / r2);
        double tend = 500;
        double t = 0;
        double pi = 4*Math.atan(1);
        double deltat = 0.01;
        double result = 0;

        while (t <= tend) {

            t = t + deltat;
            r = Math.sqrt(x * x + y * y);
            r2 = Math.sqrt(x2 * x2 + y2 * y2);

            double posx = mittelpunktx + x;
            double posy = mittelpunkty + y;
            double posx2 = mittelpunktx + x2;
            double posy2 = mittelpunkty + y2;
            double poswechselx = posx2 - posx;
            double poswechsely = posy2 - posy;
            double rwechselq = poswechselx * poswechselx + poswechsely * poswechsely;

            double a = 0.00001 * gamma * ((m / r) / r);
            double a2 = 0.00001 * gamma * ((m / r2) / r2);
            double avon1auf2 = 0.00001 * gamma * (m2 / rwechselq);
            double avon2auf1 = 0.00001 * gamma * (m1 / rwechselq);

            alpha = winkel(x,y,alpha);
            alpha2 = winkel(x2, y2, alpha2);
            alpha3 = winkel(poswechselx, poswechsely, alpha3);
            alpha4 = alpha3 + pi;

            double ax = a * Math.cos(alpha);
            double ay = a * Math.sin(alpha);
            double ax2 = a2 * Math.cos(alpha2);
            double ay2 = a2 * Math.sin(alpha2);
            double ax3 = avon1auf2 * Math.cos(alpha3);
            double ay3 = avon1auf2 * Math.sin(alpha3);
            double ax4 = avon2auf1 * Math.cos(alpha4);
            double ay4 = avon2auf1 * Math.sin(alpha4);

            ax = ax + ax3;
            ay = ay + ay3;
            ax2 = ax2 + ax4;
            ay2 = ay2 + ay4;
            vx = vx - ax * deltat;
            vy = vy - ay * deltat;
            x = x + vx * deltat;
            y = y + vy * deltat;
            vx2 = vx2 - ax2 * deltat;
            vy2 = vy2 - ay2 * deltat;
            x2 = x2 + vx2 * deltat;
            y2 = y2 + vy2 * deltat;

            double finalx = skalierenx(posx);
            double finaly = skaliereny(posy);
            double finalx2 = skalierenx2(posx2);
            double finaly2 = skaliereny2(posy2);
            double finalmittelpunktx = skalierenx(mittelpunktx);
            double finalmittelpunkty = skaliereny(mittelpunkty);
               

            g.setColor(Color.blue);
            g.drawLine((int)(finalx),(int)(finaly),(int)(finalx),(int)(finaly));
            g.setColor(Color.red);
            g.drawLine((int)(finalx2),(int)(finaly2),(int)(finalx2),(int)(finaly2));
            g.drawLine((int)(finalmittelpunktx),(int)(finalmittelpunkty),(int)(finalmittelpunktx),(int)(finalmittelpunkty));
        //  g.drawOval((int)(finalx),(int)(finaly),);
            }
        }
public double winkel(double xposition, double yposition, double result){
    result = Math.atan(yposition / xposition);
    double pi = 4*Math.atan(1);
    if ((xposition < 0) && (yposition < 0)) {
        result = result + pi;
    }
    if ((xposition < 0 ) && (yposition > 0)){
        result = result + pi;
    }
    if ((xposition > 0) && (yposition <0)) {
        result = result + 2*pi;
    }
    return result;
        }


public double skalierenx(double posx){
    double minPointX = 508.0;
    double maxPointX = 366.594;
    double screenX = (posx - minPointX) * getWidth() / (maxPointX - minPointX);

    return screenX;
        }
public double skaliereny(double posy){
    double minPointY = 497.66;
    double maxPointY = 337.468;
    double screenY = (posy - minPointY) * getWidth() / (maxPointY - minPointY);

    return screenY;
        }
public double skalierenx2(double posx2){
    double minPointX2 = 508.0;
    double maxPointX2 = 366.594;
    double screenX2 = (posx2 - minPointX2) * getWidth() / (maxPointX2 - minPointX2);

    return screenX2;
        }
public double skaliereny2(double posy2){
    double minPointY2 = 497.66;
    double maxPointY2 = 337.468;
    double screenY2 = (posy2 - minPointY2) * getWidth() / (maxPointY2 - minPointY2);

    return screenY2;
        }
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Success");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JComponent newContentPane = new Success();
        frame.setContentPane(newContentPane);

        frame.setPreferredSize(WINDOW_SIZE);
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
class myButtonListener implements ActionListener{
    Circle c;
   myButtonListener(Circle c){
       this.c=c;
   }
    public void actionPerformed(ActionEvent ae){
        c.m1 = c.m1+1500;
        c.repaint();
        }
    }

}
   

[Fred Wagner]

I can only repeat myself again: thank you so much Mr. Johnson.


I have found a strange issue to occur, on my brother's desktop (windows) my planets draw all at once, on my own box it paints step by step... is this intended?

is there a way to change it so that it is painted step by step instead of all at once?








Thanks again,



Fred

[R Johnson]

Computers take code and execute it as fast as it possibly can so on different computers will often have different results though often it's not noticable. Even different OS's will have different run times. So no it's not intended to be step by step. On my computer with the codes you've given the results are instantaneous. The only way that I would know how to ensure some lapse of time (again different machines different results) would be to create a thread that draws each planet. I'm not sure what we're calling planets I'm assuming the red line is one and the blue line is the other. In BASIC all you had to do to slow things down was create a large loop, not a good idea in Java. So the only way I could see is a rewrite of the program to seperate the lines perhaps create a class called planets that holds all a planets variables then in the run you could populate the variables and call repaint after each one. In paintComponent you would still paint the objects now part of this planet class but the variables set to 0 until populated. Here's an example of a thread though I'm pretty sure it doesn't use good programming practices and hopefully someone will comment on my errors and we can both learn!

    
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Ship extends JPanel implements Runnable{
    int i=0;
   JTextArea jta=new JTextArea();
    Thread t=new Thread(this);
    Ship(){

       jta.setPreferredSize(new Dimension(100,100));
       jta.setLineWrap(true);
       add(jta);


    }
    public void run(){
        boolean drawingplanets=true;
        
            
        while(drawingplanets){
               doSomeMethod();
                if(i>30)
               drawingplanets=false;
        }
    }
    public void doSomeMethod(){
        jta.setText(jta.getText()+" "+ i);
        i++;
        try{
            t.sleep(100L);
        }catch(Exception ex){

        }

    }
    public static void main(String[] args){
        JFrame jf=new JFrame();
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Ship s=new Ship();
        Thread t=new Thread(s);
        t.start();

        jf.add(s);
        jf.pack();
        jf.setVisible(true);


    }

}