There is a scrollview in the below image (red area 1 + 2 + 3).
What I am trying to achieve is that: if I scroll up, firstly the area 1 will be up and hidden to top, then area 2 will be pinned to top and keep unmoved, area 3 can still be scroll up/down.
If I scroll down, after area 3 reaches its top, area 2 and 3 will go down together and area 1 will appear again.
Which layout could I follow?
