NestedScrollView and CoordinatorLayout. Issue on Scrolling

Question

I have a strange issue with the CoordinatorLayout and the NestedScrollView (with the design support library 22.2.0)

Using a content smaller

Answer 1

The onMeasureChild() method is called many times during the layout process. Apparently, the key is getting a non-zero value for the child height early in the process. ScrollingViewBehavior fails to do so in the following:

int scrollRange = appBar.getTotalScrollRange();
int height = parent.getHeight() 
             - appBar.getMeasuredHeight()
             + scrollRange;

FixedScrollingviewBehavior fixes this with:

int height = parent.getHeight() 
             - appBar.getMeasuredHeight() 
             + Math.min(scrollRange, parent.getHeight() - heightUsed);

which very early gives height the value of -128, the height of the app bar.

An alternative, close to the original is:

int height = parent.getMeasuredHeight()
             - appBar.getMeasuredHeight()
             + scrollRange;