File level changes by an Android app How can I track the file level changes done by an application during execution on an Android device. Specifically I am interested in file level changes done by a malware - create, delete, save a file on the device.

While searching this forum I found one way is - /proc//fd. Is there any other way ? using logcat,Frida or any other way ?
Other than the options you mentioned, 
There's a seriously long way to do this, the best way in my opinion.   

It's very basic and effective, I used this method to find the files or folders that KingRoot modified, created or deleted.  

It's one of the oldest methods around,
Compare a base image &amp; after install image.


Backup the device ( in stock condition is better )   


system
data
( call it Base Image )

Install and run the application   
Backup the device again
( call it Test Image )
Transfer the backups to a PC   
Extract the backup's into two separate folders   
Use a comparison tool to test for differences between the folders    
Identify any Deleted, Modified &amp; Created data   


I used WinMerge or something like that, it is designed to help merge folders, however it is enough to do the comparison. 

You can also compare the compressed images without extraction by using a Hex editor that has file comparison tools.  

I use HxD Hex Editor to compare files on PC.