Although styles are great for

applying certain attributes to individual views, what if we wanna think bigger and

apply certain characteristics to entire parts of our application?

Do we have to manually create a style for each view and apply it one by one?

That certainly seems like a very tedious process, and

that's exactly why Android has a concept of themes.

Themes are applied globally, either to the entire application to certain activities

and now, with the release of Android Lollipop 5.0, can be applied to Views.

In this course our app only requires a very simple theme globally, and

one that's just ever slightly more complex for the settings activity.

So we'll go ahead and create that in the next video.

Although simple, themes in Android are incredibly powerful and

you'll see just how useful they are when we can do in two lines of

code what would normally have taken us as many lines as Views in our layouts.

If you're fairly new to Android you might not have experienced the mess that theming

your application used to be.

Due to the varied nature of Android, and

the fact that some users are still on much older versions, we had to back port or

create different versions of your styles that would work on different versions

of Android, depending on how far back you want it to support.

Now Android comes with a really cool library called AppCompat, so

we don't have to worry about most of that hard work.

We're going to use AppCompat soon, but

first, I wanna take advantage of the power of themes.

In the next video we're going to write four lines of code to style

the entire settings activity just the way we like.

After that we'll provide motivation for why we wanna use

the backwards compatible themes and show you how to make one yourself.