Field Naming Conventions for Android

• Non-public, non-static field names start with m.
• Static field names start with s.
• Other fields start with a lower case letter.
• Public static final fields (constants) are ALL_CAPS_WITH_UNDERSCORES.
  
  

For example:

public class MyClass {
    public static final int SOME_CONSTANT = 42;
    public int publicField;
    private static MyClass sSingleton;
    int mPackagePrivate;
    private int mPrivate;
    protected int mProtected;
}

http://source.android.com/source/code-style.html