Android Design Support Library And Material Design

Question

I'm new here, so bear with me! I'm sorta confused about the new Design Support Library (and how one implements support libraries), and I had a two questions:

• I'm confused about how support libraries are implemented. Is it something as simple as saying 'if the OS version is below version 5.0, use the V7 support library', or would I have to code an 'Alternative Layout'(One for devices running +5.0, and one for devices running older version of android?)
• Does the Design Support Library replace or add-to the V7 support libraries? (If I wanted to include, say, cards and a snack bar in an app, would I be able to just use the Design Support Library or would I have to use it along with the v7 cardview library? I know it's a stupid question, but I just want to make sure.)

Thanks a lot!

Answer 1

I'm confused about how support libraries are implemented. Is it something as simple as saying 'if the OS version is below version 5.0, use the V7 support library', or would I have to code an 'Alternative Layout'(One for devices running +5.0, and one for devices running older version of android?)

The libraries takes care for you of compatibility for pre-Lollipop (and pre-M) devices for the views contained in it.

Does the Design Support Library replace or add-to the V7 support libraries? (If I wanted to include, say, cards and a snack bar in an app, would I be able to just use the Design Support Library or would I have to use it along with the v7 cardview library? I know it's a stupid question, but I just want to make sure.)

Add-to. The design support library contains some views exclusive for helping to achieve a perfect "materialized" app. For RecyclerView, CardView, Palette etc, you must use their separate support libraries. E.g.:

compile 'com.android.support:appcompat-v7:22.2.0'
compile 'com.android.support:cardview-v7:22.2.0'
compile 'com.android.support:recyclerview-v7:22.2.0'
compile 'com.android.support:design:22.2.0'

Answer 2

You can use the support libraries to backport some features introduced with the last api (for example 21) to old devices running a previous api level.

For example, API21 introduced a new widget, the Toolbar. This widget can be used only in device with API >=21.

With the appcompat rel.21 (a v7 Support library) you can use the Toolbar (pay attention to the package) to implement your Toolbar in old devices running API>=7.

This can happen because the support libraries are included in your apk.

The Design Support Library is a new library which add new features. It contains views as Snackbar, TextInputLayout, FloatingActionButton, but it doesn't contain the Card.

So use this dependency for the design support library:

compile 'com.android.support:design:22.2.0'

This dependency to use the AppCompat library

compile 'com.android.support:appcompat-v7:22.2.0'

This dependency for the official CardView

compile 'com.android.support:cardview-v7:22.2.0'

Check the official doc for more info.