Android how can I get current positon on recyclerview that user scrolled to item

Question

In my RecyclerView I have some items that user can scroll and see that. Now I want to save this position and scroll that after come back. This below code return 0 always and I can't save that:

recyclerMarketLists.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
    @Override
    public void onScrollChanged() {
        recyclerViewCurrentScrolledPosition = recyclerMarketLists.getScrollY();
        Log.e("Y: ", recyclerViewCurrentSceolledPosition + "");
    }
});

the Logcat:

07-07 18:28:30.919 2124-2124/com.sample.presentationproject E/Y:: 0

Joaquim Ley · Accepted Answer · 2018-07-17 13:25:15Z

73

You are trying to get the info on the wrong object. It is not the RecyclerView nor the Adapter responsibility but the RecyclerView's LayoutManager.

Instead of the generic ViewTreeObserver.OnScrollChangedListener() I would recommend to add instead the RecyclerView.OnScrollListener and use the onScrollStateChanged(RecyclerView recyclerView, int newState) callback which gives you the newState, you should use SCROLL_STATE_IDLE to fetch its position. Meaning:

yourRecyclerView.getLayoutManager().findFirstVisibleItemPosition();

As Rik van Velzen pointed out, you probably need to cast your LayoutManager to a LinearLayoutManager or GridLayoutManager (you have to cast to the correct type you are using) to access these findVisibleXXXX() methods.

On said callback method. Hope I made this clear enough for your, you can find documentation on the classes here:

RecyclerView.OnScrollListener

yigit's (Google) response on visible positions

edited Jul 17, 2018 at 13:25

answered Jul 7, 2016 at 14:25

Joaquim Ley

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8 Comments

Joaquim Ley Over a year ago

linearLayoutManager.scrollToPositionWithOffset(intemIndex, pxFromTop); If it was helpful please upvote my answer.

DolDurma Over a year ago

is this correct: recyclerView.scrollToPosition(recyclerViewLastPosition);

Joaquim Ley Over a year ago

Yes. You can also use smoothScroll for visual candy

pamobo0609 Over a year ago

When I call the scrollToPosition it never ends scrolling. Any clues?

Rik van Velzen Over a year ago

You might need to cast the LayoutManager to a Linear or GridLayoutManager etc. when calling getLayoutManager() to be able to call findFirstVisibleItemPosition()

|

Vahe Gharibyan · Accepted Answer · 2018-06-09 18:11:16Z

34

Thanks for solution Joaquim Ley. This helps create recyclerView horizontal pager without using any library.

Init recyclerView

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_vocabulary_list);

    // Set up the recyclerView with the sections adapter.
    mRecyclerView = findViewById(R.id.list);
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
    mRecyclerView.setAdapter(new VocabularyListAdapter<>(vocabularyList));
    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            if (newState == RecyclerView.SCROLL_STATE_IDLE){
                int position = getCurrentItem();
                onPageChanged(position);
            }
        }
    });
    PagerSnapHelper snapHelper = new PagerSnapHelper();
    snapHelper.attachToRecyclerView(mRecyclerView);
}



public boolean hasPreview() {
   return getCurrentItem() > 0;
}

public boolean hasNext() {
    return mRecyclerView.getAdapter() != null &&
            getCurrentItem() < (mRecyclerView.getAdapter().getItemCount()- 1);
}

public void preview() {
    int position = getCurrentItem();
    if (position > 0)
        setCurrentItem(position -1, true);
}

public void next() {
    RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
    if (adapter == null)
        return;

    int position = getCurrentItem();
    int count = adapter.getItemCount();
    if (position < (count -1))
        setCurrentItem(position + 1, true);
}

private int getCurrentItem(){
    return ((LinearLayoutManager)mRecyclerView.getLayoutManager())
            .findFirstVisibleItemPosition();
}

private void setCurrentItem(int position, boolean smooth){
    if (smooth)
        mRecyclerView.smoothScrollToPosition(position);
    else
        mRecyclerView.scrollToPosition(position);
}

answered Jun 9, 2018 at 18:11

Vahe Gharibyan

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3 Comments

DolDurma Over a year ago

Thanks a lot, please let me to check that :)

Vahe Gharibyan Over a year ago

PagerSnapHelper control scroling for item to item like ViewPger

Joaquim Ley Over a year ago

Glad I could help out, although it seems like you are creating objects every time your RecyclerView is touched, not sure this is the most performant.

Mattia Ferigutti · Accepted Answer · 2021-06-28 16:17:21Z

19

This is the extension function in Kotlin:

fun RecyclerView?.getCurrentPosition() : Int {
    return (this?.layoutManager as LinearLayoutManager).findFirstVisibleItemPosition()
}

You can use it just invoking this function on your RecyclerView:

val position = yourRecyclerView.getCurrentPosition()

edited Jun 28, 2021 at 16:17

answered Jul 22, 2020 at 8:07

Mattia Ferigutti

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1 Comment

ansh sachdeva Over a year ago

its not advisiable to direct cast via as and use !! . instead, nullable casting via as? followed by elvis (?:0) is much safer

reza_khalafi · Accepted Answer · 2021-04-20 10:15:02Z

5

Try this in Kotlin:

myRecyclerView.addOnScrollListener(object: RecyclerView.OnScrollListener() {
    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        super.onScrolled(recyclerView, dx, dy)
        val offset: Int = myRecyclerView.computeHorizontalScrollOffset()
        if (offset % myRecyclerView.width == 0) {
            val position: Int = offset / myRecyclerView.width
            Log.e("Current position is", position.toString())
        }
    }
})

answered Apr 20, 2021 at 10:15

reza_khalafi

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Comments

P Toles · Accepted Answer · 2018-09-20 14:17:35Z

I made 7 changes in my MainActivity and got pixel-perfect results. My recyclerview ALWAYS remembers its previous state when returning to it from some other Activity (e.g. DetailActivity).

Step 1: Initialize the layoutManager like so:

    // Initialize the layout manager
    moviePosterLayoutManager = (moviePosterRecyclerView.getLayoutManager() == null) ?
    new GridLayoutManager(this, numberOfColumns) :  moviePosterRecyclerView.getLayoutManager();
            // create a new layoutManager                       // reuse the existing layoutManager

Step 2: Inside your MainActivity class, create a STATIC variable to hold your layout manager state as you transition between activities:

private static Parcelable layoutManagerState;

Step 3: Also create this constant inside of the MainActivity () as well:

public static final String KEY_LAYOUT_MANAGER_STATE = "layoutManagerState";

Step 4: Inside the onCreate method for your MainActivity perform the following test, (i.e.

protected void onCreate(@Nullable final Bundle savedInstanceState) {....

    if (layoutManagerState != null) {
        //moviePosterLayoutManager
        moviePosterLayoutManager.onRestoreInstanceState(layoutManagerState);
        moviePosterRecyclerView.setLayoutManager(moviePosterLayoutManager);

    } else {

        moviePosterRecyclerView.setLayoutManager(moviePosterLayoutManager);
        moviePosterRecyclerView.scrollToPosition(moviePosition);
                                 // the default position

    }

Step 5: In your onSaveInstanceState method, be sure to save your layoutManagerState as a parcelable like so:

protected void onSaveInstanceState(Bundle outState) {

   layoutManagerState = moviePosterLayoutManager.onSaveInstanceState();

    // Save currently selected layout manager.            
   outState.putParcelable(KEY_LAYOUT_MANAGER_STATE,layoutManagerState);
}

Step 6: Place similar code in the onResume() method of MainActivity:

protected void onResume() {
    super.onResume();


    if (layoutManagerState != null) {
        moviePosterLayoutManager.onRestoreInstanceState(layoutManagerState);
    }

}

Step 7: Remember that all of this code was placed inside of my MainActivity.java file It is important to remember that the layoutManager is responsible for maintaining the scroll position of the recycler view. So, saving the state of the layoutManager is of paramount importance. The code could modularized and placed inside a custom recyclerview, but I found this to be simpler for me to implement.

theThapa · Accepted Answer · 2019-03-28 18:23:49Z

2

For a similar requirement plus some action needed to be performed on scroll state changed, I did this with a custom scroll listener:

class OnScrollListener(private val action: () -> Unit) : RecyclerView.OnScrollListener() {

private var actionExecuted: Boolean = false
private var oldScrollPosition: Int = 0

override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
    super.onScrollStateChanged(recyclerView, newState)
    when (newState) {
        RecyclerView.SCROLL_STATE_DRAGGING -> actionExecuted = false
        RecyclerView.SCROLL_STATE_SETTLING -> actionExecuted = false
        RecyclerView.SCROLL_STATE_IDLE -> {

            val scrolledPosition =
                (recyclerView.layoutManager as? LinearLayoutManager)?.findFirstVisibleItemPosition() ?: return

            if (scrolledPosition != RecyclerView.NO_POSITION && scrolledPosition != oldScrollPosition && !actionExecuted) {
                action.invoke()
                actionExecuted = true
                oldScrollPosition = scrolledPosition
            }

        }
    }
}

}

This is because of the pre-existing bug with RecyclerView onScroll which happens to trigger the callback 2-3 or even more times. And if there is some action to be performed, that will end up executing multiple times.

answered Mar 28, 2019 at 18:23

theThapa

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2 Comments

Reyhane Farshbaf Over a year ago

Can you explain where and how to use this class, plz? TNX.

theThapa Over a year ago

@ReyhaneFarshbaf You can use this class where you use the recycler view e.g. in Fragment or Activity. You can create a new instance of the ScrollListener by passing an action lambda. Then attach it to the recycler view like: recyclerView.addOnScrollListener(scrollListener)

Sheetal Shinde · Accepted Answer · 2021-05-31 14:44:12Z

1

    learnRecycleView
        .addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView,
                                   int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                int offset=learnRecycleView.computeHorizontalScrollOffset();

                if (offset % learnRecycleView.getWidth() == 0) {
                    int position = offset / learnRecycleView.getWidth();
                    System.out.println("Current position is"+position);
                }
            }
        });

answered May 31, 2021 at 14:44

Sheetal Shinde

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Comments

Happy Singh · Accepted Answer · 2021-06-02 13:34:44Z

None of the solutions worked, I have achieved this by using layout manager. Here is the Extension function for recyclerview

fun RecyclerView.addScrollListener(onScroll: (position: Int) -> Unit) {
    var lastPosition = 0
    addOnScrollListener(object : RecyclerView.OnScrollListener() {
        override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
            super.onScrolled(recyclerView, dx, dy)
            if (layoutManager is LinearLayoutManager) {
                val currentVisibleItemPosition =
                    (layoutManager as LinearLayoutManager).findFirstVisibleItemPosition()

                if (lastPosition != currentVisibleItemPosition && currentVisibleItemPosition != RecyclerView.NO_POSITION) {
                    onScroll.invoke(currentVisibleItemPosition)
                    lastPosition = currentVisibleItemPosition
                }
            }
        }
    })
}

You can use it like this on recyclerview.

 campusFeedRv.addScrollListener { position: Int ->
            Log.d(TAG, "Current Position: $position ")
  }

Tippu Fisal Sheriff · Accepted Answer · 2021-06-19 11:15:12Z

1

In my case, I need my current position view in Activity so I create a call-back method and using the below method.

Add this code in the Adapter class to get the current position of view.

Add this in onBindViewHolder method.

holder.imgProductParts.addOnAttachStateChangeListener(new View.OnAttachStateChangeListener() {
            @Override
            public void onViewAttachedToWindow(View v) {
                onPositionChangeListener.onItemChanged(position);
            }

            @Override
            public void onViewDetachedFromWindow(View v) { }
        });

answered Jun 19, 2021 at 11:15

Tippu Fisal Sheriff

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Comments

Muhammad Ammar · Accepted Answer · 2022-06-10 07:40:32Z

Kotlin Extension Way

Will return the recycler view current item position

Extension Function ==>

fun RecyclerView.onScrollDoneGetPosition(onScrollUpdate: (Int) -> Unit) {
    this.addOnScrollListener(object :
        RecyclerView.OnScrollListener() {
        override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
            super.onScrolled(recyclerView, dx, dy)
        }

        override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
            super.onScrollStateChanged(recyclerView, newState)
            when (newState) {
                AbsListView.OnScrollListener.SCROLL_STATE_FLING -> {
                }
                AbsListView.OnScrollListener.SCROLL_STATE_IDLE -> {
                    print("When User Done it's Scroll")
                    val currentPosition =
                        ([email protected] as LinearLayoutManager).findFirstVisibleItemPosition()
                    onScrollUpdate.invoke(currentPosition)
                }
                AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL -> {
                }
            }
        }
    })
}

Usage ==>

yourRecyclerView.onScrollDoneGetPosition() { pos ->
 populateData(pos)
}

Additional ==>

recycler view only one item per swipe restriction

 val snap = PagerSnapHelper()
 snap.attachToRecyclerView(yourRecyclerView)

## Happy codding ##

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