i thinking if possible access other apps' folder in ios? example, installed x application , want access x's files?
i know ios doesnt allow it, if jailbreaked device? , same question android? need root access app's files? , same question windows phone?
a short answer android no (unless have root access) , according the documentation:
android privilege-separated operating system, in each application runs distinct system identity (linux user id , group id). parts of system separated distinct identities. linux thereby isolates applications each other , system.
i don't know ios , windows phone permissions, natural if don't give access freely. you'll have jailbreak.