In the Palette column of Design—the online part of App Inventor—we find the Other Stuff drawer (see the following screenshot) toward the bottom:
Let's go through these, starting with the most powerful component in all of App Inventor land: the ActivityStarter.
Both Google and, now, myself have made a big thing of how App Inventor insulates you from having to know and use all that esoteric, confusing Java code (shudder).
The Glorious Googlelab Geeks (and I mean that as a very positive compliment) have gone to great lengths and continue to do so in developing this "shuffle around a few blocks" app-building playhouse for us.
However, there are still a very few "holes" in the floor—places where it is still necessary to occasionally reach down and grasp a handful of code (just wash afterwards, eh?).
The ActivityStarter is perhaps the most complex component—due to having to type in actual Java code in Design to set it up. Drag an ActivityStarter component onto the virtual...