Android :: Hello World Button Display Random Number

Brand new to droid programming, but would love to learn as much as possible, so I finally got my emulator working correctly, I even got a hello world button to work. I'm attempting to make this button display a random number, I've googled this and came up with this code:

Random generator = new Random();
int n = generator.nextInt(n);

I fixed the Random function by including some Random java utility. I'm assuming this code above goes in the .java file of the project, so my button code looks as follows (tested and works):

PopUpText.makeText(v.getContext(), "Hello World",
PopUpText.LENGTH_LONG).show();

I figured I could replace "Hello World" with n to display the number in the box, however the following error is stopping the compile:
The local variable n may not have been initialized