Force header height to min

Hi,

My layout is as follow : 

```
LAYOUT
|_ HEADER
|_ PAGER
   |_ MapView
   |_ RecyclerView
|_ Floating action button
```

When pushing the FAB, I want to animate the header to min height (if necessary) and show the map view. When pushing the FAB again, I would like to show the recycler view again (and leave the header minimized)

Any way to do that?
