DocsWork is the best viewer for Microsoft Word, Excel, Powerpoint and PDF. DocsWork is a great app for word processing, spreadsheets, presentations and pdf.
The DocsWork module to view Microsoft Word and text files provides an internal document viewer that does not need the Internet. The rest of the formats requires the Internet in order to use a LibreOffice conversion engine.
Available in the Google Play Store: https://play.google.com/store/apps/details?id=org.dandroidmobile.offiedit
DocsWork supports a great number of file formats:
* LibreOffice file formats: ODT, ODS, ODP, OTT and ODM, which are used not only by LibreOffice but by OpenOffice.
* Microsoft Office formats: DOC, XLS, PPT, DOCX, XLSX and PPTX, which are used by the programs Microsoft Excel, Word and PowerPoint.
* Adobe reader format: PDF.
* Standard file text formats: TXT and RTF.
* Other formats like CWK, HTML, PDB, DXF, CSV, CDR, XML, EPS, GIF, PDF, BPN, JPG, SVG, WPD and XBM.
DocsWork also contains very useful functionalities:
* A File Explorer, which can be used to browse the whole list of files located in the Android device.
* File searches grouped by the types Microsoft Word, Excel, Powerpoint and PDF in order to find any document very quickly.
* A text editor to create text files.
* File Sharing to export and share any document with DropBox, Google Drive, Email, SkyDrive, ...
* File Import. DocsWork can be opened from the apps Gmail, K9Mail, Yahoo Mail.
DocWork is based on Apache POI and LibreOffice so it is free to use. It is available in many languages..