How to Recover Deleted File in Mac OS X?
Notice before Recovery
Actually, the files are still there, you just removed the directory entries, not the files themselves. The the space will be marked as free and available for new data. But writing to the drive will overwrite the space once occupied by the deleted files which will lead to the recovery failure. Also, save the existed modified files will also have chance to overwrite the deleted files.
Remember, the longer the hard drive remains in use and data are written to it, the greater the risk your deleted files will be overwritten.