Android/Java: How to remove the filetype extention from a URI?

So I am working with URIs in Android to set ringtones for individual contacts. Problem is, the way the ringtone selector works is that it doesn't like something such as myringtone.mp3. Instead, it just wants myringtone. Weird, but I guess that's just how it goes. So I have a URI like file:///sdcard/tag/ringt开发者_StackOverflow中文版ones/ringtone.mp3. How would I get the URI to remove the extension so the ringtone manager uses it properly? The way ringtones are set are with this line:

values.put(ContactsContract.Contacts.CUSTOM_RINGTONE, uri.toString());

So the URI is in string form. Using substrings I should be able to do it, but I don't know how I'd write a method to remove the final 4 characters in a string. Can anyone give me some advice here?

Thanks!

For situations where you don't know what the extension may be or unknown length, try:

uri.toString().substring(0, uri.getString().lastIndexOf("."));

Have you tried?...

uri.toString().substring(0, uri.toString().length() - 4);