My Class Day 3 - Structure of Android Project

Android Application :

Code + Data = Application
  |
       (Business Logic + Presentation Logic) + Data

Business Logic - Java - 
Project/src/package/ .java files

Presentation Logic - XML - 
Project/layout/ .xml files

Data - XML 
Project/values/ .xml files

class Activity
{
     // 80% code
}
class MyActivity extends Activity
{
    // you have to execute 80% code present in super class - super.method(data);
    // 20% code
}