MIDLET EXAMPLE TO GENERATE RANDOM ARITHMETIC GAME PUZZLE

import java.util.*;

import javax.microedition.lcdui.*;

import javax.microedition.midlet.*;

import java.util.Random;



public class CanvasForm extends MIDlet implements CommandListener{

    private Display display;

    private Form form;

    private Displayable current;

    private TextField one, two, opp;

    private StringItem item;

    private String txt;

    private long result;

    private Command quit, next ;

    private CanvasClass canvas;

    int first=0, second=0;



    public CanvasForm(){}



    public void startApp(){

        display=Display.getDisplay(this);

        form = new Form("welcome to maths game");

        form.append("This is your first question...");

        

        one = new TextField(null,"", 1, TextField.ANY );

        one.setMaxSize(200);

        random();

        two = new TextField(null,"", 1, TextField.ANY );

        two.setMaxSize(200);

        randomnum();

        opp = new TextField(null,"", 1, TextField.ANY );

        opp.setMaxSize(200);

        randomopp();

        

        item = new StringItem("Result", "");        



        quit = new Command("Quit", Command.EXIT, 0);

        next = new Command("Next", Command.SCREEN, 0);

        form.append(one);

        form.append(two);

        form.append(item);

        form.append(opp);

        

        form.addCommand(next);

        form.addCommand(quit);

        form.setCommandListener(this);

        display.setCurrent(form);

        

    }



    public void pauseApp(){}



    public void destroyApp(boolean b){}

      

    public void commandAction(Command c, Displayable s){

        if (c == quit){

            notifyDestroyed();

            return;

        }

        

        calculate();



        if (canvas==null) canvas= new CanvasClass() ;

        current=canvas;

        display.setCurrent(canvas);

    }    





    private void calculate(){

        try {

            first = Integer.parseInt( one.getString() );

            second = Integer.parseInt( two.getString() );

            result = first + second ;

            item.setText( result + "" );

        } catch (NumberFormatException e){

            item.setText("unknown");

            e.printStackTrace();

        }

    }



    public void random(){

        Random number = new Random();

        int f = number.nextInt(10);

           number.setSeed(System.currentTimeMillis());    

          one.setString(""+f);     

    }



    public void randomnum(){

        Random number = new Random();

        int f = number.nextInt(10);

        number.setSeed(System.currentTimeMillis());    

        two.setString(""+f);

    }



    public void randomopp(){

        Random operator = new Random();

        int f = operator.nextInt('+');

        int f1 = operator.nextInt('-');

        int f2 = operator.nextInt('*');

        operator.setSeed(System.currentTimeMillis());    

        opp.setString(""+f);

        opp.setString(""+f1);

        opp.setString(""+f2);

    }



    class CanvasClass extends Canvas implements CommandListener{

        CanvasClass(){

            this.addCommand( new Command("Back", Command.BACK, 0 ) );

            this.setCommandListener(this);

        }



        protected void paint(Graphics g){

            int w = getWidth();

            int h = getHeight();

            g.setColor(244,244,244);

            g.fillRect( 0,0,w,h );

            g.setGrayScale(12*14);

            h = Math.min( w, h );



            long mf = 100000000;

            int angle = (int)(( (first*(36000*mf/result)) +50*mf)/(100*mf)) ;

            int origin=180;

            g.fillArc(0,0,h,h, origin, (int)angle);

            g.setGrayScale(13*16);

            g.fillArc(0,0,h,h, (int)(origin+angle), (int)(360-angle) );

            

            g.setColor(123);

            g.drawString("A = "+first+"  ", h/2, h/2-10, Graphics.BASELINE|Graphics.RIGHT);

            g.drawString("  B = "+second, h/2, h/2-10, Graphics.BASELINE|Graphics.LEFT);

            g.drawString("Total = "+(first+second), h/2, h/2, Graphics.TOP|Graphics.HCENTER);



        }



        public void commandAction( Command c, Displayable d){

            current=form;

            display.setCurrent(form);

        }

    }

}