I'm looking to develop an Android app where users can pay for and download publications (mostly teaching materials, possibly books, pamphlets, etc.) to their phone. I'm trying to figure out which document format to use, but am unsure what is out there and what would suit my needs. The needs I see:
- Renders well in a mobile environment (PDF & HTML are probably out)
- Allows for text, images, hierarchy (table of contents, sections, chapters, etc.) at a minimum. 2b. Preferably with an option to eventually have embedded video & sound (though these aren't deal breakers)
- Has a free / open source rendering engine/library (my budget doesn't allow for a lot)
- Supports download to the device for offline viewing (so no Google Docs or similar)
- Easily supports search features via API or built-in to a derived View class
- Is a format that publishers can already use without me needing to create document editing tools.
- Can be embedded into the application (no firing off Intents or similar)
I envision an app that can be taken into classroom environments, whether on a phone or tablet, and be used to have the teacher's notes, downloaded materials, etc. for reference or possibly output to a display if the device has HDMI out or similar.
What is available to do this, if anything? If something doesn't exactly fit the bill, is there anything that's kind of close where maybe some glue logic or similar could round it out into something usable?