Android: Widget, AppWidget, Fragment, Activity and App - What's the difference?
<p>I've got a lot of experience with Java and C#, but I'm new to Android. I mainly use C# because I am enamored of the Control hierarchy. I love the plug-and-play of the ontology. I'm trying to understand the ontology in this new paradigm and I may have been given some false information.</p>

<p>With respect to Apps, that should be the largest component. Within the App, there may be several Activities. An activity can display a number of Fragments. AppWidgets appear to be a special case as they exist as a component of the App, but are shown on their own. And I was told that you can extend Buttons or ProgressBar to create your own components which again appear to be called Widgets.</p>

<p>As I said, I may have this completely wrong. Ideally I would like to create my own widgets which I can put on a Fragment, an AppWidget or an Activity; any of which I might compose into an App. All the online sources I've found only discuss Widget in the sense of an AppWidget? Was I given incorrect information? Can anyone clarify the ontology?
Thanks</p>