My First Java Mobile aap

PFont font;//Create a Font named font
String s;// String that contains operator symbol
int opp;// Used to choose the operator from 1 to 4
int x,y,ans;// x and y being the randomly generated values and ans contains its answer, according to their operator


int count=1;//is used as the power of 10
int uans=0;//User's answer
String ua="";//User's Answer






void setup(){
  softkey("Submit");//To create a softkey label named Submit
  
  
  font = loadFont("ArialMT-48.mvlw",#FFFFFF);
  textFont(font);

  
  
  opp = random(1,4);//To randomly generate operator
  x=random(1,100);//To randomly generate number
  y=random(1,100);//To randomly generate number




}




void draw(){


background(0);
fill(255,0,0);


rect(0,0,width/3,height/4);
rect(2*width/3,0,width,height/4);




if(opp==1){//Addition operator
 s = "+"; 
 ans=x+y;
}
if(opp==2){//Subtraction Operator
 s = "-";
  ans=x-y;
}
if(opp==3){//Multiplication Operator
 s = "X"; 
  ans=x*y;
}
if(opp==4){//Division Operator
 s = "/"; 
  ans=x/y;
}




text("" + x, width/10, height/6);
text("" + y, 3*width/4, height/6);
text(s, width/2-15, 20, width/2, height/2);
text("" + uans, 0, height/2);


text(ua, 0, 5*height/6);  


}




void keyPressed(){
if (key =='0'){
  uans = (uans*pow(10,count)) + 0 ;


}
if (key =='1'){
  uans = (uans*pow(10,count)) + 1 ;


}
 if (key =='2'){
  uans = (uans*pow(10,count)) + 2 ;
   
}
if (key =='3'){
  uans = (uans*pow(10,count)) + 3 ;
   
}
if (key =='4'){
  uans = (uans*pow(10,count)) + 4 ;


}
if (key =='5'){
  uans = (uans*pow(10,count)) + 5 ;

}
if (key =='6'){
  uans = (uans*pow(10,count)) + 6 ;
   
}
if (key =='7'){
  uans = (uans*pow(10,count)) + 7 ;

}


if (key =='8'){
  uans = (uans*pow(10,count)) + 8 ;
   
}


if (key =='9'){
  uans = (uans*pow(10,count)) + 9 ;


}
if (key =='*'){
  uans = uans;
}
if (key =='#'){
  uans = uans*-1;


}
}




void softkeyPressed(String label) {
    if (label.equals("Submit")) {
      if(uans==ans){
        ua="Correct";
      } 
      else 
        ua="Wrong";  
    }
    
}