Drawing program trouble
import java.awt.*;
import javax.swing.*;
import java.applet.*;
publicclass Drawextends Applet
{
Button erase =new Button("erase");
Button blue=new Button("Blue");
Button red=new Button("Red");
Button green=new Button("Green");
Button black=new Button("Black");
Button gray=new Button("Gray");
Button cyan=new Button("Cyan");
Button white=new Button("White");
Button magenta=new Button("Magenta");
DrawPanel canvas;
publicvoid init()
{
canvas =new DrawPanel(getImage(getCodeBase(),"halojesus.jpg"));
BorderLayout bord =new BorderLayout();
setLayout(bord);
add(canvas,"Center");
Panel commandPanel =new Panel();
commandPanel.add(erase);
commandPanel.add(blue);
commandPanel.add(red);
commandPanel.add(green);
commandPanel.add(black);
commandPanel.add(gray);
commandPanel.add(cyan);
commandPanel.add(white);
commandPanel.add(magenta);
add(commandPanel,"South");
}
publicboolean action(Event evt, Object obj)
{
if(evt.target == erase)
{
canvas.numPoints = -1;
canvas.repaint();
}
elseif(evt.target==blue)
screen.setColor(Color.blue));
elseif(evt.target==red)
screen.setColor(Color.red);
elseif(evt.target==green)
screen.setColor(Color.green);
elseif(evt.target==white)
screen.setColor(Color.white);
elseif(evt.target==gray)
screen.setColor(Color.gray);
elseif(evt.target==cyan)
screen.setColor(Color.cyan);
elseif(evt.target==magenta)
screen.setColor(Color.magenta);
elseif(evt.target==black)
screen.setColor(Color.black);
returntrue;
}
}
class DrawPanelextends Panel
{
Image picture;
int[] drawX =newint[1000];
int[] drawY =newint[1000];
int numPoints = -1;
publicvoid paint(Graphics screen)
{
screen.drawImage(picture,0,0,this);
screen.setColor(Color.black);
for(int i = 0;i<= numPoints;i++)
{
screen.fillOval(drawX[i]-3, drawY[i]-3,6,6);
}
}
publicvoid update(Graphics screen)
{
paint(screen);
}
publicboolean mouseDown(Event evt,int x,int y)
{
if(numPoints <1000)
{
numPoints++;
drawX[numPoints] = x;
drawY[numPoints] = y;
}
repaint();
returntrue;
}
publicboolean mouseDrag(Event evt,int x,int y)
{
mouseDown(evt, x, y);
returntrue;
}
DrawPanel(Image inputImage)
{
picture = inputImage;
}
}
The compiling errors I get are these:
Draw.java:44: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.blue);
^
Draw.java:46: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.red);
^
Draw.java:48: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.green);
^
Draw.java:50: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.white);
^
Draw.java:52: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.gray);
^
Draw.java:54: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.cyan);
^
Draw.java:56: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.magenta);
^
Draw.java:58: cannot resolve symbol
symbol : variable screen
location: class Draw
screen.setColor(Color.black);
^
8 errors
I know the reason for these errors: screen is in DrawPanel and I am trying to use it from Draw. What can I do about it, though? Thanks.
