Deleting a file from BroadcastReceiver

Deleting a file from BroadcastReceiver

I have a class that calls a BroadcastReceiver. I am struggling to delete a
file when it's called.
If I use deleteFile("file.txt") within the class it works and deletes the
file.
However if I try deleteFile("file.txt") within the BroadcastReceiver class
it won't work.
Any ideas on how I can delete a file within a BroadcastReceiver class? I
have tried many different ways and I an guessing there is something
fundamental I'm missing.
Thanks in advance for any help.