Difference between v4 and v13 suport library in Android

Question

Hello I was checking support library page on android doc where I found v13 library also. I use v4 in my projects.

I understood that v4 is required If I set the minSDKVersion between 4-12 and If I set it to >=13 then I should use v13 support library.

Question

What is the use of support library v13 if we have already native Fragment classes if I set minSDKVersion to 13 because native Fragment is already from API 11 http://developer.android.com/reference/android/app/Fragment.html.

and Why they divided it into v4 and v13 if we have all features of v13 in v4 ?

Answer 1

What is use of support library v13 if we have already native Fragment classes

You may not want to use the native Fragment classes. For example, nested fragments was only added to the native Fragment classes in API Level 17 -- if you wanted nested fragments on older devices, you have to use the backport.

Why they divided it into v4 and v13 if we have all features of v13 in v4 ?

Not every class in support-v13 works back to API Level 4. Notably, support-v13 has implementations of FragmentPagerAdapter and FragmentStatePagerAdapter that work with native fragments. support-v13 is a superset, not identical to, support-v4.