This blog post is also an article on how to get the Android Device Manager on your Android phone / tablet
In certain circumstances, Google Play services on Android may not show up on Google's Play Store (unless you have its URL). When this happens, on your Android device, uninstall the old version of Google Play services, and then install Google Hangout, or run Hangout if you've already installed it. Since Hangout requires Google Play services, this will force Google Play services to install.
Once your Google Play services are updated, you will see Android Device Manager when you open up the Google Settings application (which is a green icon with a g and a gear at the top right).
Finally, to access your Android Device Manager online, go to https://www.google.com/android/devicemanager?u=0.
In 2017, with the release of Delphi 10.2 Tokyo, Embarcadero introduced a specialized implementation of the Observer pattern into the System.Classes unit. While it has been in the wild for 9 years, it remains a "hidden" architecture for many, primarily because it serves as the invisible engine behind LiveBindings. Other than live bindings, you can also use the Observer pattern as a way to update component settings to the Windows registry, an .ini file, or persist it elsewhere.
System.Classes