Question

The assignment is to take the current program that draws a line and to add 4 buttons at the bottom of the frame that will change the line drawn to a different color (ie. No button pressed draws a black line, Button labeled Red changes any new lines drawn to red and retains any previously colored lines, etc for all the buttons). This is the code I have so far but I'm having issues with the buttons. This is also done entirely with AWT and no Swing. We can't use Swing with this program.

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

public class MyNewDrawFrame extends Frame{
        
        public MyNewDrawFrame(){
                        setSize(500,500);
                        setTitle("Drawing is fun");
                        addWindowListener(new WindowAdapter(){
                                public void windowClosing(WindowEvent we){
                                        System.exit(0);
                                }
                        });
                        MyNewDrawPanel mdp = new MyNewDrawPanel();
                        add(mdp);
                        setVisible(true);
        }
        public static void main(String[] args){
                MyNewDrawFrame mdf = new MyNewDrawFrame();
        }
}
class MyNewDrawPanel extends DoubleBuffer implements MouseListener, MouseMotionListener{

        int lastX=0, lastY=0;
        ArrayList<Line>lines;
        Color drawColor;

        public MyNewDrawPanel() {
                lines = new ArrayList<Line>();
                setBackground(Color.white);
                drawColor = Color.black;
                setForeground(drawColor);
                addMouseListener(this);
                addMouseMotionListener(this);
        }
        public void mouseExited(MouseEvent me){}
        public void mouseClicked(MouseEvent me){}
        public void mouseReleased(MouseEvent me){}
        public void mouseEntered(MouseEvent me){
                record(me.getX(), me.getY());
        }
        public void mousePressed(MouseEvent me){
                record(me.getX(), me.getY());
        }
        public void mouseMoved(MouseEvent me){}
    public void mouseDragged(MouseEvent me){
                int x = me.getX();
                int y = me.getY();
                lines.add(new Line(lastX, lastY, x, y));
                record(x, y);
                repaint();
    }
        public void paint(Graphics g){
                for(Line line: lines){
                        g.drawLine(line.getStartX(), line.getStartY(), line.getEndX(), line.getEndY());
                }
        }
        protected void record(int x, int y) {
                lastX = x;
                lastY = y;
        }
}
class Line{

        int startx, starty, endx, endy;
        
        public Line(){}
        public Line(int startx, int starty, int endx, int endy){
                setStartX(startx);
                setStartY(starty);
                setEndX(endx);
                setEndY(endy);
        }
        public void setStartX(int startx){
                this.startx = startx;
        }
        public void setStartY(int starty){
                this.starty = starty;
        }
        public void setEndX(int endx){
                this.endx = endx;
        }
        public void setEndY(int endy){
                this.endy = endy;
        }
        public int getStartX(){
                return startx;
        }
        public int getStartY(){
                return starty;
        }
        public int getEndX(){
                return endx;
        }
        public int getEndY(){
                return endy;
        }
}

this is the supplemental program for MyNewDrawFrame called DoubleBuffer

import java.awt.*;

public class DoubleBuffer extends Panel{

        private int bufferWidth;
        private int bufferHeight;
        private Image bufferImage;
        private Graphics bufferGraphics;


    public DoubleBuffer(){
        super();
    }

        public void update(Graphics g){
                paintBuffer(g);
        }

        public void paintBuffer(Graphics g){
        //    checks the buffersize with the current panelsize
        //    or initialises the image with the first paint
        if(bufferWidth!=getSize().width || bufferHeight!=getSize().height ||bufferImage==null || bufferGraphics==null)
                        resetBuffer();
                if(bufferGraphics!=null){
                //this clears the offscreen image, not the onscreen one
                bufferGraphics.clearRect(0,0,bufferWidth,bufferHeight);

                    //calls the paintbuffer method with 
                //the offscreen graphics as a param
                paint(bufferGraphics);

                //we finaly paint the offscreen image onto the onscreen image
                g.drawImage(bufferImage,0,0,this);
        }
                        
        }

        public void paint(Graphics g){
                //in classes extended from this one, add something to paint here!
                //always remember, g is the offscreen graphics
        }
        private void resetBuffer(){
        // always keep track of the image size
        bufferWidth=getSize().width;
        bufferHeight=getSize().height;

                //    clean up the previous image
        if(bufferGraphics!=null){
                bufferGraphics.dispose();
                bufferGraphics=null;
        }
        if(bufferImage!=null){
                bufferImage.flush();
                bufferImage=null;
        }
        System.gc();

                //    create the new image with the size of the panel
        bufferImage=createImage(bufferWidth,bufferHeight);
        bufferGraphics=bufferImage.getGraphics();
        }
}

The code for the buttons should be implemented in the first program, MyNewDrawFrame.

Thanks in advance for any help.