Q:

Android terminology and how to set panel's beckground image

I am new to Android. So new that I am not even clear on the terminology. From the user perspective, one can swipe from one page (iOS term) to another on Android. I have been told that these are called "panels" - but googling that term, I find out about the notification panel - which seems to be what iOS would call the status bar. Or, perhaps, these are called "home screens"
I would like to find out if there is a way to change the background image as the user swipe from one page/panel(?) to another. For example, I might want my game apps to have a green background and my social media apps to have a blue background. If this can be done by setting a panel's background image, that would be good. If there's a hack with wallpapers, that would be okay, too.
Any pointers to Android UI guideline doc that names visual entities would be great. Likewise, any pointers to a glossary of Android UI terms would also be wonderful.
Thanks in advance.
UPDATE: 
I have just come across "live wallpaper" and am wondering if this - with onOffsetsChanged() - is the way to go.

A:

In regards to the widget questions the term has two meanings: the UI components provided by the API such as TextView, Button, and WebView and the other meaning is an icon on the launcher that does more than start an app.  The latter is also referred to as App Widget and an example of this would be music player controls or weather report. Both kinds of widgets are documented at the Android Developer website.
Wallpapers are typically Live or static. Live Wallpapers are similar in idea to screensavers but do not have the same function as screensavers are for inactivity. They can also be interactive. Static wallpapers are generally bitmaps that are cropped for the situation or specially made for the dimensions. In addition a Launcher (which is the name of the "desktop application" and the Launcher Home being the "Desktop") can be replaced to provide additional features for wallpapers. For your specific question about having an image gallery style wallpaper, the vanilla Launcher does not support this.

