File Monitor (com.gmail.heagoo.filemon) on Google Play
File Monitor is designed to monitor file accesses in SD card in real time. It could be used for:(1) Finding out where the file is downloaded/saved. Some apps may save files on SD card, without telling you where it is. In such case, this tool helps.(2) Helping us to figure out if there is some suspicious file accesses.(3) For developers, it could also help to optimize file access pattern, make sure file is closed, etc.