How would I/is there any way to let the user select a file from my Application? For example, I'm making a book reading app, so I'd like to let the user be able to select an appropriate file. Is there any guaranteed way to give the user this ability?
I don't think there's a built-in widget for letting a user select a file - phone apps tend not to work with files a lot, or at least not to make it explicit to the user that they do. You could check out a few file managers (like IO Filemanager and AndExplorer) to see how they work.