Buttons in panel gives error

Question

i created a class that has many buttons and each button calls something on a Canvas.
but i keep getting errors.
THE ERROR ARE
C:\WINDOWS\Desktop\WINDOWS\pickdraw\ShapeButtons.java:36: local variable drawArea is accessed from within inner class; needs to be declared final
drawArea.setShape(1);
^
1 error
THE CODE IS
import java.awt.*;
import java.awt.event.*;
import java.lang.*;
import java.lang.String.*;
import java.awt.Graphics.*;
public class ShapeButtons extends Panel implements ItemListener
Checkbox fill = new Checkbox("Filled");
Choice sel;
PickCanvas drawArea;
Button rect, oval, poly, del, clear;
public ShapeButtons(PickCanvas drawArea)
this.drawArea= drawArea;
sel = new Choice();
add(sel);
sel.add("selected");
sel.add("deselected");
rect = new Button( "Rect" );
ActionListener lis1 = new ActionListener()
public void actionPerformed( ActionEvent e )
drawArea.setShape(1);
rect.addActionListener( lis1 );
oval = new Button( "Oval" );
ActionListener lis2 = new ActionListener()
public void actionPerformed( ActionEvent e )
drawArea.setShape(2);
oval.addActionListener( lis2 );
poly = new Button( "Poly" );
ActionListener lis3 = new ActionListener()
public void actionPerformed( ActionEvent e )
drawArea.setShape(3);
poly.addActionListener( lis3 );
del = new Button( "Delete" );
ActionListener lis4 = new ActionListener()
public void actionPerformed( ActionEvent e )
drawArea.delete();
del.addActionListener( lis4 );
clear = new Button( "Clear" );
ActionListener lis5 = new ActionListener()
public void actionPerformed( ActionEvent e )
drawArea.clearCanvas();
clear.addActionListener( lis5 );
add(rect);
add(oval);
add(poly);
add(del);
add(clear);
add(fill);
fill.addItemListener(this);
getSel().addItemListener(this);
getSel().select("deselected");
public Choice getSel()
          return sel;
public void setSelected(String s)
     getSel().select(s);
public void itemStateChanged(ItemEvent e)
if(e.getItemSelectable() == fill)
drawArea.setFill(fill.getState());
if(getSel().getSelectedItem().equalsIgnoreCase("selected"))
               drawArea.setSelect(1);
     else if(getSel().getSelectedItem().equalsIgnoreCase ("deselected"))
               drawArea.setSelect(2);
IN THE PICKCANVAS I DO HAVE A METHOD WHICH IS:
public void setShape(int action)
this.action = action;
AND I DECLARED ACTION IN THIS CANVAS AS int action;
SO I DON'T KNOW WHAT'S WRONG. HELP.     

Answer 1

drawArea is defined as a member variable of ShapeButtons, so normally it should be usable from an anonymous inner class as you are trying to use it. However, you have named a parameter of the constructor with the same name as the member variable. This means that when you use that variable name, you are referring to the local variable. If local variables are not final, then they cannot be used in inner classes defined within that function. You have three options:
1) Rename the constructor parameter so that drawArea always refers to the member variable.
2) Declare the constructor parameter final with the final keyword.
3) Refer to the drawArea inside the inner classes using the 'qualified this' variable.
The third option is the one I would use, the first being my second choice and the second option the last.
Inside the inner class, 'this' refers to the instance of the inner class. You can refer to the instance of the outter class associated with that instance by prepending the name of the enlosing class with a '.' to the 'this' keyword. For example:
public ShapeButtons(PickCanvas drawArea) {
    this.drawArea= drawArea;
    rect = new Button( "Rect" );
    ActionListener lis1 = new ActionListener() {
        public void actionPerformed( ActionEvent e ) {
            //ShapeButtons.this refers to instance of enclosing class
            ShapeButtons.this.drawArea.setShape(1);
}I was being nice and I answered your question, but next USE CODE TAGS!!!
E. West