ShortcutBadger is a library that adds an abstraction layer over the device brand and current launcher and offers a great result. Works with LG, Sony, Samsung, HTC and other custom Launchers.
It even has a way to display Badge Count in Pure Android devices desktop.
Updating the Badge Count in the application icon is as easy as calling:
int badgeCount = 1;
ShortcutBadger.applyCount(context, badgeCount);
It includes a demo application that allows you to test its behavior.