N Docs allow you view create and edit documents on Android. No internet connection is required.

* View file types :

- Microsoft Word(DOC/DOCX)
- Microsoft Excel(XLS/XLSX)
- Microsoft PowerPoint(PPT/PPTX)
- Portable Document Format(PDF password protected supported)
- RTF
- TXT
- MARKUP(MD/HTML/XHTML/XML/DTD/XSL/XSLT...)
- CODE(JAVA/CPP/PHP...)
- EBOOK(EPUB)
...

* Create file types :
- PDF
- TXT
- HTML
...

* Edit file types :
- TXT
- MARKUP(MD/HTML/XHTML/XML/DTD/XSL/XSLT...)
- CODE(JAVA/CPP/PHP...)
...