Description: This is a prototype app, demonstrating how to use Android's file observer class to watch for file changes in the public file system using the inotify subsystem in Linux. This is a fully functioning app, but it is not "polished", as such it is most intended as an example.
Specifically, there is a bug in older versions of the Android SDK documents which suggest that the FileObserver object is recursive when watching a directory (i.e. it will watch child directories). This is false. However, this code should provide an example of how to achieve this functionality by simply recursively creating FileObservers (please note that when monitoring many directories, this may carry heavy memory burden).
Architecture: 1 - Activity (FileMonitorActivity): This class, provides the user interface for starting and stopping the monitoring service. 1 - Service (FileMonitorService): Runs as a persistent foreground service which creates FileObserverNodes and keeps a live reference to the object so that the FileObserver classes are not garbage collected as per the docs. 1 - Other Class (FileObserverNode): This class extends the FileObserver class, and implements some additional functionality. Specifically, objects of this class know the fully qualified path they are watching, as well as the data structure which contains all of the access data.
Origin: November 24, 2011 Last Updated: November 24, 2013 - Ported to Android Studio + API level 19