Android feature rich PDF viewer/editor for free

Question

I was looking for an Android app for a complete management of PDF files (reading, searching, editing and so on) that was as feature rich as possible and FREE.

As first to notice, I came across several free PDF reader/viewer which seems to be like clones the one of the other and that I consider rubbish: who can go with apps that sacrifice reading space for ads?

Of course I tried the Google "default" PDF reader but it only provides basic reading functions.

The Adobe Acrobat app (I had to try that too, obviously) could be ok but it offers very little in editing features for free (things like page-reordering, document creation/modify, etc. all requires paid subscription).

For the same reason I could mention Moon+ Reader or Universal Book Reader which I look at quickly and looks nice (Moon+ Reader in particular) but I have to keep them aside because they're more intended as readers than editors and come with very limited editing features while I am looking for a unique app to install and do everything with. At the same time, I don't want to install some "dispersive" office bundle application with PDF features/add-ons but something that is mainly focused on PDF documents.

So... What else can I use for my needs?

EDIT: following @NicolasRaoul comment I list minimum edit features requested that the app must provide:

• rich annotation capabilities = at least highlights, underlines, free text, shapes (at least arrows and rectangles), notes/comments;
• form filling with signatures.

The features to add new pages, rotate/rearrange pages and create new PDF documents from scratch would be a plus.

If ads are present, they must not be intrusive ones and they must in no way be shown while reading (distracting and stealing space).

Finally, the app must be able to open multiple documents and provide a comfortable way to easily switch between them.

Answer 1

I did my homeworks and dig out an answer for myself. I write it down hoping someone else might find it useful. Yet any suggestions will be very welcome and appreciated.

After tried more of the available apps, I came out with 3 that caught my attention and deserve some words:

• Xodo PDF reader/editor;
• Foxit MobilePDF lite;
• PDF Reader Classic (I think is the same as Lirbi Book Reader but more frequently updated).

Xodo is the only one of the listed that lets you create new PDF documents from scratch, rotate/rearrange pages, add new pages and images, also it's the most user friendly in my opinion. It provides TDI so to switch easily between open documents, it integrates definitions/translation/search of selected text & minor text-to-speech capabilities. The only negative aspect could be it's about 15/20mb greater than the other two.

Foxit has slightly better annotation features than Xodo (provide comments replies and call outs). Files management is a little better too. It provides file protection and let's you take screen shot of partial or entire page (you can obtain a similar thing with Xodo but only by cropping and exporting... not so convenient way).

The last in the list is the only that has ads, thus not intrusive ones, it is the less user friendly (a bit confused indeed) and has fewer annotation features compared with the first two I mentioned BUT it is the only that has "musician mode" (document auto scrolling at specified speed), page splitting (useful to read multi-column documents on devices with smaller display) and text-to-speech for entire document with possibility to even change reading volume, speed and voice pitch (that can be funny to play with).

The choice was, clearly, between the first two, I decided to go with Xodo In the end because it is very versatile and totally free.