ContentObserver quick example

gistfile1.java

// references internal ContentObserver class
SettingsObserver observer = new SettingsObserver(new Handler());
// start watching for changes
observer.observe();
// where we do our work
updateSettings();

// Anonymous inner class to handle watching Uris
    class SettingsObserver extends ContentObserver {
        SettingsObserver(Handler handler) {
            super(handler);
        }

        void observe() {
            ContentResolver resolver = mContext.getContentResolver();
            // set our watcher for the Uri we are concerned with
            resolver.registerContentObserver(
                    Settings.System.getUriFor(Settings.System.MY_SUPER_SWEET_MOD_0),
                    false, // only notify that Uri of change *prob won't need true here often*
                    this); // this innerclass handles onChange

            // another watcher
            resolver.registerContentObserver(Settings.System.getUriFor(
                    Settings.System.MY_SUPER_SWEET_MOD_1), false, this);
        }

        @Override
        public void onChange(boolean selfChange) {
            // if changes occurred in either of the watched Uris updateSettings()
            // updateSettings() is a normal void method that will be called to handle all changes
            // or you could just do your work here but presumable the same work will need to be done
            // on load of your class as well... but you get the picture
            updateSettings();
        }
    }

    private void updateSettings() {
        // do work
    }

For the people who are really here to understand the use of Content Observer and how to implement it in our own Android App, you can visit
Use Android ContentObserver To React On Content Changes

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