(For rooted devices only!) DiskDigger can undelete and recover lost photos, documents, videos, music, and more from your memory card or internal memory (see supported file types below). Whether you accidentally deleted a file, or even reformatted your memory card, DiskDigger's powerful data recovery features can find your lost files and let you restore them, send them to an email account, or upload them to an FTP server.
For complete instructions, please see http://diskdigger.org/android
Again, this app is for rooted devices only! This is also a work-in-progress app (and not nearly as powerful as the original DiskDigger for Windows), so all constructive feedback and requests for features are welcome!
DiskDigger recovers the following file types: JPG, PNG, MP4 / M4A / 3GP / MOV, GIF, MP3, WAV, TIF, CR2, SR2, NEF, DCR, PEF, DNG, ORF, DOC / DOCX, XLS / XLSX, PPT / PPTX, PDF, XPS, ODT / ODS / ODP / ODG, ZIP, APK, EPUB.