I was having this problem too, until I realized that I had specified the wrong layout in
setContentView() of the
onCreate() method of the FragmentActivity.
The id passed into
FragmentTransaction.add(), in your case
R.id.feedContentContainer, must be a child of the layout specified in
You didn’t show us your
onCreate() method, so perhaps this is the same problem.
This error also occurs when having nested Fragments and adding them with getSupportFragmentManager() instead of getChildFragmentManager().
The solution was to use
when calling from a fragment. If you are calling the method from an activity, then use
That will solve the problem.