I'm a C++ and C# programmer and I've been practicing to make android applications to expand my knowledge. Upon downloading eclipse and the android SDK I started off with vogella's basic tutorial for a temperature converter. After doing that tutorial I continued onto a menu tutorial where I came upon problems. Here is a link to the tutorial:Android Development Tutorial - Gingerbread I'm on #7 and upon creating the preferences.xml file and adding the two attributes it told me to insert code. It doesn't specify where to put this code and I assumed it would be in the HelloPreferences.java file since there are no other available files to add activities to. Then it says to modify the manifest file to make it an actual activity. I did that step but the program still tells me that the Preferences activity needs to be defined in its own file. I looked online for solutions to adding a new activity and everyone says either to make a .java file or to add a period in-front of the activity name inside of the manifest file. I tried the period solution and that doesn't solve anything. Is there something in the tutorial that's obvious and I've missed it? I'm so lost and I really want to learn how to make android platform programs. I would greatly appreciate any help.