Pages must fill the whole ViewPager2 (use match_parent)

I have found out that the problem is in inflating view holder.

I had the same issue and solved it changing

ViewBinding.inflate(inflater)

to

ViewBinding.inflate(inflater, parent, false)

While struggling with this problem, I figured it out what's the problem was. My use case was I was using androidx.viewpager2.widget.ViewPager2, and calling normal Views in RecyclerView.

If you notice the error carefully you would see something like this:

 java.lang.IllegalStateException: Pages must fill the whole ViewPager2 (use match_parent)    at androidx.viewpager2.widget.ViewPager2$2.onChildViewAttachedToWindow(ViewPager2.java:170)

Second line is the key to main issue. If you open ViewPager2.java you would see

 private RecyclerView.OnChildAttachStateChangeListener enforceChildFillListener() {    return new RecyclerView.OnChildAttachStateChangeListener() {        @Override        public void onChildViewAttachedToWindow(@NonNull View view) {            RecyclerView.LayoutParams layoutParams =                    (RecyclerView.LayoutParams) view.getLayoutParams();            if (layoutParams.width != LayoutParams.MATCH_PARENT                    || layoutParams.height != LayoutParams.MATCH_PARENT) {                throw new IllegalStateException(                        "Pages must fill the whole ViewPager2 (use match_parent)");            }        }        @Override        public void onChildViewDetachedFromWindow(@NonNull View view) {            // nothing        }    };}

Android is not taking the match_parent assigned in xml to attach views. May be future improvements would be done in next release of ViewPager2.

Anyways, for now to fix it, set layout params as MATCH_PARENT explicity.

 view.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));

This view is the parent view holding View Pager childs.

In you case it would be androidx.constraintlayout.widget.ConstraintLayout.

 view.setLayoutParams(new ConstraintLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));

set width and height in your adapter item of ViewPager2 match_parent