Inter-application files with Mobile apps; e.g. opening Email attachments

Could somebody give me some ideas on how to make inter-application file exchange in mobile apps work? Use case example: I am receiving an attachment in an Email on my mobile and I want to send the attachment to an Outsystems mobile app for further processing, for example, storing.

I am aware of the ability in iOS to define a UTI in the plist for file types, which will tell iOS to show an "open in...." dialog for your app. But how do you enable iOS or Android to send the file to the Outsystems app?

Thanks for any thoughts.

Any Ideas? I am trying to create a Cordova Plugin to accomplish getting the filename for the file stored in the iOS file system by the intra-app communication, but I am not getting it to work. I am getting compiler errors on the Cordova plugin, but I am not sure where to find details on them.......stuck.