java.lang.NullPointerException at android.support.v7.widget.RecyclerView.onMeasure

Question

I try to use RecyclerView with RecyclerView.Adapter but here is something wrong. I post my code below:

Layout:

Answer 1

I got this error when my RecyclerView had no LayoutManager. Adding this code fixed the problem:

recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));