What if i have more than 10 Facts.

Noman,

Those are very interesting and thoughtful questions. Lets dive in!

1) Would i have to put all those facts in FactBook like other 10 Facts?

A) No, even if you leave the project in the state it is in as a simple application with a String array of facts in the FactBook class, you will pretty much have to update that array with the 1000 facts. However, this could be done in many ways. Especially considering that it is public and violating encapsulation. Therefore, you could add facts within the class as it is currently done, add facts in the class using a parser to parse a text file, or even create a new array in the OnCreate method of the FunFactActivity class like so:

      String[] moreFacts = new String[12]; //or 1000

                for(int i = 0; i < mFactBook.mFacts.length; i++) {  //copy the other facts into new array
                    moreFacts[i] = mFactBook.mFacts[i];
                }

                mFactBook.mFacts = moreFacts; //references the new array back into the FactBook class

                //add new facts
                mFactBook.mFacts[10] = "Android Rocks!";
                mFactBook.mFacts[11] = "You Rock!";

This is not a good way as you might have realized. The project here is for learning and not on the scale of a commercially viable product. Later in the course, we will learn about persistent data etc. Databases are a great way for doing this for instance. Also, I recommend taking the java course unless you already have a solid understanding of Java and Object Oriented Programming.

2) would there be any affect on Speed of app if i add more data in FactBook? A) Welcome to time complexity. Computer science terminology that is above and beyond the scope of this assignment. The basic answer is no. Why? Because the random method inside the FactBook class generates a number and that number is used to access the array in constant time. When I say I want the 50th item in an array for instance, then I just access it at the intended index of the array. Even when we loop over 1000 items in an array one after the other, we are going through them in linear time. That is also a good place to be with time complexity. It is when we get to quadratic or exponential time complexity that we want to think about our implementation. Of course, we also need to think about space complexity sometimes as well. Do we really want a String array to hold 1 billion facts? 1 Trillion? There are some good youtube videos on the subject and even MIT opencoursweare. However, I would concentrate on the basics of being able to design and develop using code skills before moving toward those concepts.

I hope this helps.

Regards,

Chris