Construção de Telas com Canvas

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class tela extends MIDlet implements CommandListener {

    private final int corblack = 0x000000;
    private final int corwhite = 0xffffff;
    private final int corred = 0xff0000;
    //private final int corblue = (40,80,150);
    //private final int corgreen = (100,200,180);
    private final int corciano = 0xc3d9ff;
    private final int corgray = 0x777777;
    //private final int coryellow = (230,200,30);
    private Command cmdExit;
    private Command cmdCriar;
    private Display display;
    private Displayable tela;

    public tela() {
        cmdExit = new Command("Exit", Command.EXIT, 1);
        cmdCriar = new Command("Criar", Command.SCREEN, 1);
    }

    public void startApp() {
        
        /* O erro acontece aqui:
         * # an enclosing instance that contains tela.criobj.cpo is required #
        */
        tela = new criobj.cpo(25, corciano, 10, 10, 200, 80);

        //criobj.cpo Razao = new criobj.cpo(25,corciano,10,10,200,80);
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }

    public void commandAction(Command c, Displayable d) {
        if (c == cmdExit) {
            destroyApp(false);
            notifyDestroyed();
        }
    }

    class criobj extends Canvas {

        public int cont;
        public int num_lbl, lastnum_lbl, num_cpo, lastnum_cpo;
        private boolean setCPO;
        private boolean setLBL;
        public String cpo_s;
        public int cpo_len, cpo_c, cpo_posX, cpo_posY, cpo_w, cpo_h;
        public String lbl_s;
        public int lbl_c, lbl_bc, lbl_posX, lbl_posY, lbl_w, lbl_h;

        class cpo extends criobj {

            cpo(int length, int cor, int x,
                    int y, int width, int height) {
                cpo_len = length;
                cpo_c = cor;
                cpo_posX = x;
                cpo_posY = y;
                cpo_w = width;
                cpo_h = height;
                setCPO = true;
                num_cpo += 1;
            }
            //###########################
            //COR

            public void setColor(int cor) {
                this.cpo_c = cor;
            }

            public int getColor() {
                return this.cpo_c;
            }
            //###########################
            //VALUE

            public void setValue(String str) {
                if (str.length() <= cpo_len) {
                    this.cpo_s = str;
                    repaint();
                }
            }

            public String getValue() {
                return this.cpo_s;
            }

            public void setLen(int length) {
                this.cpo_len = length;
            }
            //###########################
            //POSIÇÃO X e Y

            public void setX(int x) {
                this.cpo_posX = x;
            }

            public void setY(int y) {
                this.cpo_posY = y;
            }

            public int getX() {
                return this.cpo_posX;
            }

            public int getY() {
                return this.cpo_posY;
            }
            //###########################
            //LARGURA e ALTURA

            public void setW(int width) {
                this.cpo_w = width;
            }

            public void setH(int height) {
                this.cpo_h = height;
            }

            public int getW() {
                return this.cpo_w;
            }

            public int getH() {
                return this.cpo_h;
            }
        }

        class lbl extends criobj {

            lbl(int cor, int bcolor, int x,
                    int y, int width, int height) {
                lbl_c = cor;
                lbl_bc = bcolor;
                lbl_posX = x;
                lbl_posY = y;
                lbl_w = width;
                lbl_h = height;
            }
            // ###########################
            // VALUE

            public void setValue(String str) {
                this.lbl_s = str;
                setLBL = true;
                repaint();
            }

            public String getValue() {
                return this.lbl_s;
            }
            // ###########################
            // COR

            public void setColor(int cor) {
                this.lbl_c = cor;
            }

            public int getColor() {
                return this.lbl_c;
            }
            // ###########################
            // COR FUNDO

            public void setBColor(int cor) {
                this.lbl_bc = cor;
            }

            public int getBColor() {
                return this.lbl_bc;
            }
            // ###########################
            // POSIÇÃO X e Y

            public void setX(int x) {
                this.lbl_posX = x;
            }

            public void setY(int y) {
                this.lbl_posY = y;
            }

            public int getX() {
                return this.lbl_posX;
            }

            public int getY() {
                return this.lbl_posY;
            }
            // ###########################
            // LARGURA e ALTURA

            public void setW(int width) {
                this.lbl_w = width;
            }

            public void setH(int height) {
                this.lbl_h = height;
            }

            public int getW() {
                return this.lbl_w;
            }

            public int getH() {
                return this.lbl_h;
            }
        }

        protected void paint(Graphics g) {
            //if (num_cpo == 1) {
            if (setCPO) {
                g.setColor(150, 150, 255);
                g.fillRect(cpo_posX, cpo_posY, cpo_w, cpo_h);
                g.setColor(0, 0, 0);
                g.drawString(cpo_s, (cpo_posX + 5), (cpo_posY + 5),
                        Graphics.LEFT | Graphics.TOP);
            }
            if (setLBL) {
                g.setColor(150, 150, 255);
                g.fillRect(lbl_posX, lbl_posY, lbl_w, lbl_h);
                g.setColor(0, 0, 0);
                g.drawString(lbl_s, (lbl_posX + 5), (lbl_posY + 5),
                        Graphics.LEFT | Graphics.TOP);
            }
            //}
            //lastnum_cpo = num_cpo;
        }
    }
}