Android :: ArrayList IndexOf() Returns Wrong Index?

I have a problem with ArrayList. I'm using ArrayList like this:

CODE:.........................

Where Playlist is a class inherited from another ArrayList.

I do the following:

CODE:.........................

Later, when I use 'p' to get the index in the list:

CODE:.................

an index of '1' is returned, even though inspection of the list clearly shows that it's index '4'.

why this fails?

Same problem without indexOf(), using equals():

CODE:............

New edit:
This WORKS:

CODE:.............

Solution:
As suggested, I changed the Playlist class to not enherit from ArrayList, but rather keeping an instance privately. It turned out that I only had to implement 4 ArrayList methods.

This does the trick; Now indexOf() returns the correct object!