Change the appearance of cache files in Android

For my app I download some resources like images and small mp3 and save them in the external storage (at /mnt/sdcard/Android/data/com.example.packagename/cache for example. But I don't want that if a user explores that folder finds all the resources in a "common format".

One of my options is to remove the extensions (I know it's easy to guess the file type even if it have not extension but is a basic protection against most users)

I have noticed most of the programs that have their caches at the external storage don't hav开发者_如何转开发e their cache as raw files.

I wonder if is there any easy way (with some class or something) for "hiding" those files and access them transparently or I must implement my own system

(It is not vital that these files remain hidden but I'd like keep those resources "unknown" unless a user takes a special trouble to see them)

Thanks

You can use ObjectOutputStream, it will save data as binary data, when the user tries to open it, even using Text Editor, it will show corrupted data, and here some sample how to use it Writing objects to file with ObjectOutputStream