Several problems : function does not exist, class

Hello!

I'm a beginner. I try to make little programs with Processing for my Android phone but I have several problems:

I can build my program fine and the app works fine but :

-> when I write my code I have a lot of things underlined. For example:

void setup() {
  background(0);
}

void draw() {
  rect(60, 60, 60, 60);
}

In this code : - background is underlined and it says: "The class "PApplet" does not exist"

For rect it says: "The function "rect(int; int; int, int)" does not exist"

I repeat that the app works fine after building and transferring to the phone but having everything underlined is annoying. Any idea to solve that problem?

EDIT: Problem solved -> It works fine with Processing 3.0.1

Thanks Zpez