Scroll RecyclerView to show selected item on top

Question

I'm looking for a way to scroll a RecyclerView to show the selected item on top.

In a ListView I was able to do that by using scrollTo(x,y) and getting the top of the element that need to be centered.

Something like:

@Override
public void onItemClick(View v, int pos){
    mylistView.scrollTo(0, v.getTop());
}

The problem is that the RecyclerView returns an error when using it's scrollTo method saying

RecyclerView does not support scrolling to an absolute position

How can I scroll a RecyclerView to put the selected item at the top of the view?

Answer 1

just call this method simply:

((LinearLayoutManager)RecyclerView.getLayoutManager()).scrollToPositionWithOffset(yourItemPosition,0);

instead of:

RecyclerView.scrollToPosition(yourItemPosition);

Answer 2

If you want to scroll automatic without show scroll motion then you need to write following code:

**=> mRecyclerView.getLayoutManager().scrollToPosition(position);**

If you want to display scroll motion then you need to add following code.
=>Step 1: You need to declare SmoothScroller.

RecyclerView.SmoothScroller smoothScroller = new
                LinearSmoothScroller(this.getApplicationContext()) {
                    @Override
                    protected int getVerticalSnapPreference() {
                        return LinearSmoothScroller.SNAP_TO_START;
                    }
                };

=>step 2: You need to add this code any event you want to perform scroll to specific position.
=>First you need to set target position to SmoothScroller.

**smoothScroller.setTargetPosition(position);**

=>Then you need to set SmoothScroller to LayoutManager.
                        **mRecyclerView.getLayoutManager().startSmoothScroll(smoothScroller);**

Answer 3

I use the code below to smooth-scroll an item (thisView) to the top.
It works also for GridLayoutManager with views of different heights:

View firstView = mRecyclerView.getChildAt(0);
int toY = firstView.getTop();
int firstPosition = mRecyclerView.getChildAdapterPosition(firstView);
View thisView = mRecyclerView.getChildAt(thisPosition - firstPosition);
int fromY = thisView.getTop();

mRecyclerView.smoothScrollBy(0, fromY - toY);

Seems to work good enough for a quick solution.

Answer 4

If you are using the LinearLayoutManager or StaggeredGridLayoutManager, they each have a scrollToPositionWithOffset method that takes both the position and also the offset of the start of the item from the start of the RecyclerView, which seems like it would accomplish what you need (setting the offset to 0 should align with the top).

For instance:

//Scroll item 2 to 20 pixels from the top
linearLayoutManager.scrollToPositionWithOffset(2, 20);

Answer 5

what i did to restore the scroll position after refreshing the RecyclerView on button clicked:

if (linearLayoutManager != null) {

    index = linearLayoutManager.findFirstVisibleItemPosition();
    View v = linearLayoutManager.getChildAt(0);
    top = (v == null) ? 0 : (v.getTop() - linearLayoutManager.getPaddingTop());
    Log.d("TAG", "visible position " + " " + index);
}

else{
    index = 0;
}

linearLayoutManager = new LinearLayoutManager(getApplicationContext());
linearLayoutManager.scrollToPositionWithOffset(index, top);

getting the offset of the first visible item from the top before creating the linearLayoutManager object and after instantiating it the scrollToPositionWithOffset of the LinearLayoutManager object was called.

Answer 6

If you looking for vertical LinearLayout Manager you can achieve smooth scrolling using a custom LinearSmoothScroller:

import android.content.Context;
import android.graphics.PointF;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.LinearSmoothScroller;
import android.support.v7.widget.RecyclerView;

public class SnappingLinearLayoutManager extends LinearLayoutManager {

    public SnappingLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    @Override
    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state,
                                       int position) {
        RecyclerView.SmoothScroller smoothScroller = new TopSnappedSmoothScroller(recyclerView.getContext());
        smoothScroller.setTargetPosition(position);
        startSmoothScroll(smoothScroller);
    }

    private class TopSnappedSmoothScroller extends LinearSmoothScroller {
        public TopSnappedSmoothScroller(Context context) {
            super(context);

        }

        @Override
        public PointF computeScrollVectorForPosition(int targetPosition) {
            return SnappingLinearLayoutManager.this
                    .computeScrollVectorForPosition(targetPosition);
        }

        @Override
        protected int getVerticalSnapPreference() {
            return SNAP_TO_START;
        }
    }
}

use an instance of the layoutmanager in recycle view and then calling recyclerView.smoothScrollToPosition(pos); will smooth scroll to selected position to top of the recycler view