How to scroll to the bottom of a RecyclerView? scrollToPosition doesn't work

java

recyclerview

smooth-scrolling

adapter-data-observer

byNikita Barsukov·Aug 19, 2024

For swift scrolling to the bottom of a RecyclerView, employ layoutManager.scrollToPositionWithOffset and insert the index of the last item. This method promises an immediate jump without any animation:

// Employing the LayoutManager
LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
// Determining the last position - Hey don't forget we're zero based! 😅
int lastPosition = recyclerView.getAdapter().getItemCount() - 1;
// And there we go!
layoutManager.scrollToPositionWithOffset(lastPosition, 0);

Place this code just after your RecyclerView's data is loaded or given a refresh.

Delaying the Scrolling Operation

In certain instances, scrollToPosition might not seem to function as desired. This may be a result of the RecyclerView not fully initializing. To make sure the scrolling takes place after initialization, post the scrolling action:

recyclerView.post(new Runnable() {
    @Override
    public void run() {
        // Our ticket to the last floor of the "RecyclerView Mall"
        recyclerView.scrollToPosition(adapter.getItemCount() - 1);
    }
});

Introducing Smooth Scrolling

For an advanced user experience, a smooth scrolling animation can be added. Replace scrollToPosition with smoothScrollToPosition to achieve this:

// Like butter on a warm toast
recyclerView.smoothScrollToPosition(adapter.getItemCount() - 1);

Reverse Layouts: Handling them right

Reverse layouts bring the sandwiches upside down, and so does the RecyclerView. To deal with reverse layouts, configure the LinearLayoutManager in this way:

LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context);
linearLayoutManager.setReverseLayout(true); // This is where you will be served upside down
linearLayoutManager.setStackFromEnd(true);  // Sets your plate in the right direction!
recyclerView.setLayoutManager(linearLayoutManager);

Adapting to Data Changes

Reflecting the Scroll after Data Changes

When you refresh your adapter with fresh items, remember to let the view in on it with notifyDataSetChanged or any similar notify method before starting the scrolling process:

// Pulling the curtain up for the new data
adapter.notifyDataSetChanged();
// Taking our guest (scroll) to the new bottom
recyclerView.scrollToPosition(adapter.getItemCount() - 1);

Handling Dynamic Content

In dynamically loaded content such as chat apps, maintain the scroll position at the bottom as new messages keep arriving. Employ an AdapterDataObserver to stay updated with data changes:

recyclerView.getAdapter().registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
    @Override
    public void onItemRangeInserted(int positionStart, int itemCount) {
        super.onItemRangeInserted(positionStart, itemCount);
        // Set your scroll office at the last floor
        int totalItemCount = recyclerView.getLayoutManager().getItemCount();
        // Where were we? Oh yes, let's find out
        int lastVisiblePosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();

        // If our elevator is being set up for the first time or we need to make an upward journey, let's head straight to the top!
        if (lastVisiblePosition == -1 ||
                (positionStart >= (totalItemCount - 1) && lastVisiblePosition == (positionStart - 1))) {
            // And off we go!
            recyclerView.scrollToPosition(positionStart);
        }
    }
});

How to Steer Clear of Pitfalls

Be patient until loading completes: Trying to scroll while the RecyclerView is still loading all views doesn't go well. Wait until the layout is totally loaded!
Remember the zero-based indexing: Always subtract 1 while using getItemCount() as indexes are zero-based.
Say no to nested scrolling: Issues often pop up when a RecyclerView is nested inside a ScrollView or NestedScrollView. To avoid this, either do not nest scrollable views or turn off scrolling for the ScrollView wrapping the RecyclerView.