RecursiveFileObserverGroup

Monitors multiple files/directories recursively on Android

Summary

This module is necessitated by the fact that the FileObserver module provided by Android library (before Android Q) does not support tracking inner files or multiple paths in the same instance of FileObserver.

This module creates an abstraction layer that allows one instance of the RecursiveFileObserverGroup to watch multiple files and directories recursively.

Structure

All of the code is concisely contained within 3 files in app/src/main/java/io/timweri/recursivefileobservergroup:

• SingleFileObserver.java: almost identical to FileObserver except for it fires the onEvent of a parent SingleRecursiveFileObserver.
• SingleRecursiveFileObserver.java: recursively traverses a given directory and generates multiple SingleFileObservers to watch all of the subdirectories and files in the given directory.
• RecursiveFileObserverGroup.java: takes in a list of paths and creates one SingleRecursiveFileObserver for each path in the list.

Usage

List<String> filePaths = new ArrayList<String>;
filePaths.add("/sdcard/Download");
filePaths.add("/sdcard/Whatsapp");
...

RecursiveFileObserverGroup obvGrp = new RecursiveFileObserverGroup(filePaths, FileObserver.ALL_EVENTS);
obvGrp.startWatching();

Credits

The idea and a major part of the implementation are adapted from https://github.com/dlech/owncloud-android.