Changing JPanel Graphics g color drawing line

Question

i have a program similar to paint. and that i am trying to implement a change pen color however when i change the color, everything currently drawn is changed to the color R

Answer 1

Thanks hovercraft, i've done it looking at your code and fiddling around lol.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import javax.swing.BorderFactory;
import javax.swing.JPanel;

public class STDrawingArea extends JPanel {
    /**
     * 
     */
    private static final int DA_WIDTH = 700;
    private static final int DA_HEIGHT = 500;
    private static final Color DA_BGCOLOR = Color.WHITE;
    private static final long serialVersionUID = 1L;


    ArrayList points = new ArrayList();

    private Color currentColor;
    BufferedImage bImage = new BufferedImage(DA_WIDTH, DA_HEIGHT, BufferedImage.TYPE_INT_RGB);

    public STDrawingArea()
    {
         setBorder(BorderFactory.createLineBorder(Color.black));

         //Basic Settings for bImage
         Graphics g2d = bImage.getGraphics();
         g2d.setColor(DA_BGCOLOR);
         g2d.fillRect(0, 0, DA_WIDTH, DA_HEIGHT);
         g2d.dispose();

         addMouseListener(new MouseAdapter(){
             public void mousePressed(MouseEvent e)
             {
                points.clear();
                points.add(e.getPoint());
             }
         });

         addMouseMotionListener(new MouseAdapter() {
            public void mouseDragged(MouseEvent e) 
            {
                points.add(e.getPoint());
                repaint();
            }

             }); 

         addMouseListener(new MouseAdapter(){
             public void mouseReleased(MouseEvent e)
             {
                 points.add(e.getPoint());
                 points.clear();
                 System.out.println("mouseReleased X: "+e.getX()+"mouseReleased Y: "+e.getY());
                 repaint();
             }
         });
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(DA_WIDTH,DA_HEIGHT);
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        drawIntoBufferedImage();
        g.drawImage(bImage,0,0,null);
        freehandLines(g);

    }
    public void drawIntoBufferedImage()
    {
        Graphics g = bImage.getGraphics();
        freehandLines(g);
        g.dispose();
    }

    public void freehandLines(Graphics g)
    {
         if(points != null && points.size() > 1)
         {

             g.setColor(getCurrentColor());
              for(int i = 0; i < points.size()-1;i++)
               {
                   int x1 = points.get(i).x;
                   int y1 = points.get(i).y;
                   int x2 = points.get(i+1).x;
                   int y2 = points.get(i+1).y;
                   g.drawLine(x1, y1, x2, y2);
               }
         }
    }
    //clear drawings method
    public void clearDrawings()
    {
        if(points!=null)
        {
            points.clear();
            Graphics g = bImage.getGraphics();
            g.setColor(DA_BGCOLOR);
            g.fillRect(0, 0, DA_WIDTH, DA_WIDTH);
            g.dispose();
            repaint();
        }

    }

    public void setCurrentColor(Color currentColor) {
        if(currentColor == null)
        {
            currentColor = Color.BLACK;
        }else{
            this.currentColor = currentColor;
        }

    }

    public Color getCurrentColor() {
        if (currentColor == null)
        return Color.BLACK;
        else
        return currentColor;
    }
}

main class

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class STTestMain extends JFrame {
    STDrawingArea drawingArea = new STDrawingArea();
    public STTestMain()
    {
        //JFrame settings
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Spelling Trainer");
        setResizable(false);
        setVisible(true);


        //Panel of buttons
        JPanel buttonContainer = new JPanel();
        JButton btnRedPen = new JButton("Red Pen");
        JButton btnGreenPen = new JButton("Green Pen");
        JButton btnClear = new JButton("Clear");
        buttonContainer.add(btnRedPen);
        buttonContainer.add(btnGreenPen);
        buttonContainer.add(btnClear);
        //Drawing Area instantiation


        //Adding things to JFrame
        getContentPane().add(drawingArea);
        getContentPane().add(buttonContainer,BorderLayout.PAGE_END);
        pack();


        //button listener
        btnRedPen.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                drawingArea.setCurrentColor(Color.RED);
            }
        });

        btnGreenPen.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                drawingArea.setCurrentColor(Color.GREEN);
            }
        });

        btnClear.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                drawingArea.clearDrawings();
            }
        });
    }


    public static void main(String args[])
    {
        STTestMain test = new STTestMain();
    }

}