Detect Scroll Up & Scroll down in ListView

Question

I have the following requirement:

• At first, data for page no: 2 is fetched from the server & the items are populated in a ListView.

Considering that both the prev page & next page are available in a scenario, the following code has been added:

 if(prevPageNo > 0){
    mListViewActual.setOnScrollListener(this);
 }

 if(nextPageNo > 0){
    mListViewActual.setOnScrollListener(this);
 }

What conditions should I put to detect scroll up & scroll down on the following methods:

1. void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
2. void onScrollStateChanged(AbsListView view, int scrollState)

After the action: scroll up & scroll down is detected , accordingly a service will be called with either the prev page no or next page no , to fetch the items to be populated in the Listview.

Any inputs will be helpful.

Gone through the following links but its not returning the correct scroll up / scroll down action:

link 1 link 2

Chaco

Answer 1

try using the setOnScrollListener and implement the onScrollStateChanged with scrollState

setOnScrollListener(new OnScrollListener(){
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
      // TODO Auto-generated method stub
    }
    public void onScrollStateChanged(AbsListView view, int scrollState) {
      // TODO Auto-generated method stub
      final ListView lw = getListView();

       if(scrollState == 0) 
      Log.i("a", "scrolling stopped...");


        if (view.getId() == lw.getId()) {
        final int currentFirstVisibleItem = lw.getFirstVisiblePosition();
         if (currentFirstVisibleItem > mLastFirstVisibleItem) {
            mIsScrollingUp = false;
            Log.i("a", "scrolling down...");
        } else if (currentFirstVisibleItem < mLastFirstVisibleItem) {
            mIsScrollingUp = true;
            Log.i("a", "scrolling up...");
        }

        mLastFirstVisibleItem = currentFirstVisibleItem;
    } 
    }
  });

G

What if you want to determine scroll direction before the scollState is SCROLL_STATE_IDLE? Like when scrollState is SCROLL_STATE_FLING or SCROLL_STATE_TOUCH_SCROLL. – Insouciance

What work for me is adding this code at OnScroll not at onScrollStateChanged – Undersigned

will not work if all items are visible fore example you have 2 items and you want to scroll up like whatsapp to load more – Brevity

Answer 2

Here is a working modified version from some of the above-indicated solutions.

Add another class ListView:

package com.example.view;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.AbsListView;

public class ListView extends android.widget.ListView {

    private OnScrollListener onScrollListener;
    private OnDetectScrollListener onDetectScrollListener;

    public ListView(Context context) {
        super(context);
        onCreate(context, null, null);
    }

    public ListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        onCreate(context, attrs, null);
    }

    public ListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        onCreate(context, attrs, defStyle);
    }

    @SuppressWarnings("UnusedParameters")
    private void onCreate(Context context, AttributeSet attrs, Integer defStyle) {
        setListeners();
    }

    private void setListeners() {
        super.setOnScrollListener(new OnScrollListener() {

            private int oldTop;
            private int oldFirstVisibleItem;

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                if (onScrollListener != null) {
                    onScrollListener.onScrollStateChanged(view, scrollState);
                }
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if (onScrollListener != null) {
                    onScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
                }

                if (onDetectScrollListener != null) {
                    onDetectedListScroll(view, firstVisibleItem);
                }
            }

            private void onDetectedListScroll(AbsListView absListView, int firstVisibleItem) {
                View view = absListView.getChildAt(0);
                int top = (view == null) ? 0 : view.getTop();

                if (firstVisibleItem == oldFirstVisibleItem) {
                    if (top > oldTop) {
                        onDetectScrollListener.onUpScrolling();
                    } else if (top < oldTop) {
                        onDetectScrollListener.onDownScrolling();
                    }
                } else {
                    if (firstVisibleItem < oldFirstVisibleItem) {
                        onDetectScrollListener.onUpScrolling();
                    } else {
                        onDetectScrollListener.onDownScrolling();
                    }
                }

                oldTop = top;
                oldFirstVisibleItem = firstVisibleItem;
            }
        });
    }

    @Override
    public void setOnScrollListener(OnScrollListener onScrollListener) {
        this.onScrollListener = onScrollListener;
    }

    public void setOnDetectScrollListener(OnDetectScrollListener onDetectScrollListener) {
        this.onDetectScrollListener = onDetectScrollListener;
    }
}

And an interface:

public interface OnDetectScrollListener {

    void onUpScrolling();

    void onDownScrolling();
}

And finally how to use:

com.example.view.ListView listView = (com.example.view.ListView) findViewById(R.id.list);
listView.setOnDetectScrollListener(new OnDetectScrollListener() {
    @Override
    public void onUpScrolling() {
        /* do something */
    }

    @Override
    public void onDownScrolling() {
        /* do something */
    }
});

In your XML layout:

<com.example.view.ListView
    android:id="@+id/list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

This is my first topic, do not judge me harshly. =)

Novokuznetsk

Why not extending the scroll listener instead of the whole view? Extending the view only for the scroll event is not exactly a good practice, especially if later you want to attach a new scroll listener... – Kobylak

Answer 3

this is a simple implementation:

lv.setOnScrollListener(new OnScrollListener() {
        private int mLastFirstVisibleItem;

        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem,
                int visibleItemCount, int totalItemCount) {

            if(mLastFirstVisibleItem<firstVisibleItem)
            {
                Log.i("SCROLLING DOWN","TRUE");
            }
            if(mLastFirstVisibleItem>firstVisibleItem)
            {
                Log.i("SCROLLING UP","TRUE");
            }
            mLastFirstVisibleItem=firstVisibleItem;

        }
    });

and if you need more precision, you can use this custom ListView class:

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.AbsListView;
import android.widget.ListView;

/**
 * Created by root on 26/05/15.
 */
public class ScrollInterfacedListView extends ListView {


    private OnScrollListener onScrollListener;
    private OnDetectScrollListener onDetectScrollListener;

    public ScrollInterfacedListView(Context context) {
        super(context);
        onCreate(context, null, null);
    }

    public ScrollInterfacedListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        onCreate(context, attrs, null);
    }

    public ScrollInterfacedListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        onCreate(context, attrs, defStyle);
    }

    @SuppressWarnings("UnusedParameters")
    private void onCreate(Context context, AttributeSet attrs, Integer defStyle) {
        setListeners();
    }

    private void setListeners() {
        super.setOnScrollListener(new OnScrollListener() {

            private int oldTop;
            private int oldFirstVisibleItem;

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                if (onScrollListener != null) {
                    onScrollListener.onScrollStateChanged(view, scrollState);
                }
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if (onScrollListener != null) {
                    onScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
                }

                if (onDetectScrollListener != null) {
                    onDetectedListScroll(view, firstVisibleItem);
                }
            }

            private void onDetectedListScroll(AbsListView absListView, int firstVisibleItem) {
                View view = absListView.getChildAt(0);
                int top = (view == null) ? 0 : view.getTop();

                if (firstVisibleItem == oldFirstVisibleItem) {
                    if (top > oldTop) {
                        onDetectScrollListener.onUpScrolling();
                    } else if (top < oldTop) {
                        onDetectScrollListener.onDownScrolling();
                    }
                } else {
                    if (firstVisibleItem < oldFirstVisibleItem) {
                        onDetectScrollListener.onUpScrolling();
                    } else {
                        onDetectScrollListener.onDownScrolling();
                    }
                }

                oldTop = top;
                oldFirstVisibleItem = firstVisibleItem;
            }
        });
    }

    @Override
    public void setOnScrollListener(OnScrollListener onScrollListener) {
        this.onScrollListener = onScrollListener;
    }

    public void setOnDetectScrollListener(OnDetectScrollListener onDetectScrollListener) {
        this.onDetectScrollListener = onDetectScrollListener;
    }


    public interface OnDetectScrollListener {

        void onUpScrolling();

        void onDownScrolling();
    }

}

an example for use: (don't forget to add it as an Xml Tag in your layout.xml)

scrollInterfacedListView.setOnDetectScrollListener(new ScrollInterfacedListView.OnDetectScrollListener() {
            @Override
            public void onUpScrolling() {
               //Do your thing
            }

            @Override
            public void onDownScrolling() {

             //Do your thing
            }
        });

Doxology

It basically does not work for SMALL scrolls. This implements a "one at a time" detector. It fires only when you have scrolled "a whole cell". – Lynea

I believe this works perfectly (remembering that it is cell-wise, not pixel-wise). I tested it extensively compared to the "four tests" method below (example Elulici's answer). Hope it helps someone. – Lynea

Great and simple solution. – Inflection

Great! Works Perfectly! – Antipole

Answer 4

With all the method posted, there are problems recognizing when the user is scrolling up from the first element or down from the last. Here is another approach to detect scroll up/down:

        listView.setOnTouchListener(new View.OnTouchListener() {
            float height;
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                int action = event.getAction();
                float height = event.getY();
                if(action == MotionEvent.ACTION_DOWN){
                    this.height = height;
                }else if(action == MotionEvent.ACTION_UP){
                    if(this.height < height){
                        Log.v(TAG, "Scrolled up");
                    }else if(this.height > height){
                        Log.v(TAG, "Scrolled down");
                    }
                }
                return false;
            }
        });

Taynatayra

is this prevent touch from listView child Item, or click ? – Maid

Answer 5

            ListView listView = getListView();
            listView.setOnScrollListener(new OnScrollListener() {

                @Override
                public void onScrollStateChanged(AbsListView view, int scrollState) {

                    view.setOnTouchListener(new OnTouchListener() {
                        private float mInitialX;
                        private float mInitialY;

                        @Override
                        public boolean onTouch(View v, MotionEvent event) {
                            switch (event.getAction()) {
                                case MotionEvent.ACTION_DOWN:
                                    mInitialX = event.getX();
                                    mInitialY = event.getY();
                                    return true;
                                case MotionEvent.ACTION_MOVE:
                                    final float x = event.getX();
                                    final float y = event.getY();
                                    final float yDiff = y - mInitialY;
                                    if (yDiff > 0.0) {
                                        Log.d(tag, "SCROLL DOWN");
                                        scrollDown = true;
                                        break;

                                    } else if (yDiff < 0.0) {
                                        Log.d(tag, "SCROLL up");
                                        scrollDown = true;
                                        break;

                                    }
                                    break;
                            }
                            return false;
                        }
                    });

Safelight

This is really the best solution for this because all other solutions depend on current and last visible item. When depending on list item you also depend on adapter and if you scroll and adapter did not inflate next item you do not know if user scrolled up or down. – Ceruse

This is really BAD solution, since you are setting view touch listener EVERY time onScrollStateChanged which has a lots of overhead. – Miserly

Answer 6

My solution works perfectly giving the exact value for each scroll direction. distanceFromFirstCellToTop contains the exact distance from the first cell to the top of the parent View. I save this value in previousDistanceFromFirstCellToTop and as I scroll I compare it with the new value. If it's lower then I scrolled up, else, I scrolled down.

private int previousDistanceFromFirstCellToTop;

listview.setOnScrollListener(new OnScrollListener() {

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {

    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        View firstCell = listview.getChildAt(0);
        int distanceFromFirstCellToTop = listview.getFirstVisiblePosition() * firstCell.getHeight() - firstCell.getTop();

        if(distanceFromFirstCellToTop < previousDistanceFromFirstCellToTop)
        {
           //Scroll Up
        }
        else if(distanceFromFirstCellToTop  > previousDistanceFromFirstCellToTop)
        {
           //Scroll Down
        }
        previousDistanceFromFirstCellToTop = distanceFromFirstCellToTop;
    }
});

For Xamarin developers, the solution is the following:

Note: don't forget to run on UI thread

listView.Scroll += (o, e) =>
{
    View firstCell = listView.GetChildAt(0);
    int distanceFromFirstCellToTop = listView.FirstVisiblePosition * firstCell.Height - firstCell.Top;

    if (distanceFromFirstCellToTop < previousDistanceFromFirstCellToTop)
    {
        //Scroll Up
    }
    else if (distanceFromFirstCellToTop > previousDistanceFromFirstCellToTop)
    {
        //Scroll Down
    }
    previousDistanceFromFirstCellToTop = distanceFromFirstCellToTop;
};

Acciaccatura

Nice answer! I just had to add a check if the firstCell is null (because it could happen, that it is not inflated yet). – Antic

That's the best and simplest answer I found about detecting scroll direction ! It's right even the item height small or large, it's working perfect and stable. THANK YOU VERY MUCH. By the way, just a tiny thing, you can put previousDistanceFromFirstCellToTop variable inside inner anonymous OnScrollListener class to make it better. – Greed

Great solution! Only one thing missing: after View firstCell = view.getChildAt(0); add : if(firstCell == null){ return; } – Rasure

Answer 7

Just set scroll listener to your listview.

If you have a header or footer you should check the visible count too. If it increases it means you are scrolling down. (Reverse it if there is a footer instead of header)

If you don't have any header or footer in your listview you can remove the lines which cheks the visible item count.

listView.setOnScrollListener(new AbsListView.OnScrollListener() {
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            if (mLastFirstVisibleItem > firstVisibleItem) {
                Log.e(getClass().toString(), "scrolling up");
            } else if (mLastFirstVisibleItem < firstVisibleItem) {
                Log.e(getClass().toString(), "scrolling down");
            } else if (mLastVisibleItemCount < visibleItemCount) {
                Log.e(getClass().toString(), "scrolling down");
            } else if (mLastVisibleItemCount > visibleItemCount) {
                Log.e(getClass().toString(), "scrolling up");
            }
            mLastFirstVisibleItem = firstVisibleItem;
            mLastVisibleItemCount = visibleItemCount;
        }

        public void onScrollStateChanged(AbsListView listView, int scrollState) {
        }
    });

and have this variables

int mLastFirstVisibleItem;
int mLastVisibleItemCount;

Adventurer

This only works once you move "one whole cell". It does not detect small movements. It does work reliably. Note that it triggers when a cell border pass the bottom of the screen (or enclosing whatever), not the top. Dude I'm sure you have up and down transposed, by the way! – Lynea

I can not see any difference in function between this answer, and the simpler approach, e.g. GaiRom above. I tested corner cases etc. extensively. Was there a reason for the extra comparisons, Eluleci? – Lynea

Answer 8

I've used this much simpler solution:

setOnScrollListener( new OnScrollListener() 
{

    private int mInitialScroll = 0;

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) 
    {
        int scrolledOffset = computeVerticalScrollOffset();

        boolean scrollUp = scrolledOffset > mInitialScroll;
        mInitialScroll = scrolledOffset;
    }


    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {


    }

}

Ostrogoth

what's computeVerticalScrollOffset?? – Lynea

A protected method in ListView – Ostrogoth

thanks a million for the prompt response. I seem to be unable to use it: I just get "cannot find symbol..." I tried all of view. computeVerticalScrollOffset(), myListView.computeVerticalScrollOffset() and just calling it in your code. Sorry, I'm new to Android from iOS (and I love Android!) – Lynea

Since it's a protected method, you need to extrend ListView. – Ostrogoth

Answer 9

To also detect scrolling with larger elements, I prefere an onTouch Listener:

listview.setOnTouchListener(new View.OnTouchListener() {

        int scrollEventListSize = 5; 
        float lastY;
        // Used to correct for occasions when user scrolls down(/up) but the onTouchListener detects it incorrectly. We will store detected up-/down-scrolls with -1/1 in this list and evaluate later which occured more often
        List<Integer> downScrolledEventsHappened;

        @Override
        public boolean onTouch(View v, MotionEvent event) {

            float diff = 0;
            if(event.getAction() == event.ACTION_DOWN){
                lastY = event.getY();
                downScrolledEventsHappened = new LinkedList<Integer>();
            }
            else if(event.getAction() == event.ACTION_MOVE){
                diff = event.getY() - lastY;
                lastY = event.getY();

                if(diff>0)
                    downScrolledEventsHappened.add(1);
                else 
                    downScrolledEventsHappened.add(-1);

               //List needs to be filled with some events, will happen very quickly
                if(downScrolledEventsHappened.size() == scrollEventListSize+1){
                    downScrolledEventsHappened.remove(0);
                    int res=0;
                    for(int i=0; i<downScrolledEventsHappened.size(); i++){
                        res+=downScrolledEventsHappened.get(i);
                    }

                    if (res > 0) 
                        Log.i("INFO", "Scrolled up");
                    else 
                        Log.i("INFO", "Scrolled down");
                }
            }
            return false; // don't interrupt the event-chain
        }
    });

Lecompte

Answer 10

Store the firstVisibleItem and on the next onScroll check if the new firstVisibleItem is smaller or greater than the previous one.

Example pseudocode (not tested):

int lastVisibleItem = 0;
boolean isScrollingDown = false;

void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
    if (firstVisibleItem > lastVisibleItem) {
        isScrollingDown = true;
    }
    else {
        isScrollingDown = false;
    }
    lastVisibleItem = firstVisibleItem;
}

Lait

Implemented the above code. onScroll() is called when the user scrolls & reaches the last item of the ListView but onScroll() is not called when the user scrolls to the first visible item of the ScrollView. For the first page , first visible item: 0 . How to handle the scenario ? onScrollStateChanged() is called in both the cases. – Chaco

I have a code that onScroll is called everytime! Are you sure you have the listener up and running all the time? Set mListViewActual.setOnScrollListener(this) regardless of any condition! – Lait

I have added mListViewActual.setOnScrollListener(this) without any condition. Still the onScroll() is not called when the user tries to scroll up i.e. beyond the top visible item which is 0 in this case.Currently , as mentioned already , the user is in page no: 2. Only when the user tries to scroll up , i.e. beyond the first visible item & onScroll() is called , a next service call can be made to the server to fetch the data for page no: 1. – Chaco

Answer 11

For some reason the Android doc doesnt cover this, and the method used isnt even in the docs... took me a while to find it.

To detect if your scroll is at the top you would use this.

public boolean checkAtTop() 
{
    if(listView.getChildCount() == 0) return true;
    return listView.getChildAt(0).getTop() == 0;
}

This will check if your scroller is at the top. Now, in order to do it for the bottom, you would have to pass it the number of children that you have, and check against that number. You might have to figure out how many are on the screen at one time, and subtract that from your number of children. I've never had to do that. Hope this helps

Ours

Answer 12

Those methods cannot be used to detect scrolling directions directly. There are many ways of getting the direction. A simple code(untested) for one such method is explained below :

public class ScrollTrackingListView extends ListView {

    private boolean readyForMeasurement = false;
    private Boolean isScrollable = null;
    private float prevDistanceToEnd = -1.0;
    private ScrollDirectionListener listener = null;

    public ScrollTrackingListView(Context context) {
        super(context);
        init();
    }

    public ScrollTrackingListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public ScrollTrackingListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
        ViewTreeObserver observer = getViewTreeObserver();
        observer.addOnGlobalLayoutListener(globalLayoutListener);
        setOnScrollListener(scrollListener);
    }

    private ViewTreeObserver.OnGlobalLayoutListener globalLayoutListener
            = new ViewTreeObserver.OnGlobalLayoutListener() {

        @Override
        public void onGlobalLayout() {
            readyForMeasurement = true;
            calculateDistanceToEnd();
        }

    };

    public void registerScrollDirectionListener(ScrollDirectionListener listener) {
        scrollDirectionListener = listener;
    }

    public void unregisterScrollDirectionListener() {
        scrollDirectionListener = null;
    }

    private OnScrollListener scrollListener
            = new OnScrollListener() {

        @Override
        public void onScrollStateChanged(AbsListView absListView, int i) {
            calculateDistanceToEnd();
        }

        @Override
        public void onScroll(AbsListView absListView, int i, int i1, int i2) {
            // Do nothing
        }

    };

    private void calculateDistanceToEnd() {

        if (readyForMeasurement) {

            // I'm using the height of the layout, horizontal scrollbar and
            // content along with scroll down offset

            // computeVerticalScrollExtent is used to compute the length of the thumb within the scrollbar's track.
            // The length of the thumb is a function of the view height and the content length.
            int verticalScrollExtent = computeVerticalScrollExtent();
            int verticalScrollOffset = computeVerticalScrollOffset();
            int verticalScrollRange = computeVerticalScrollRange();
            int horizontalScrollBarHeight = getHorizontalScrollbarHeight();

            /**
             * 1. Let "R" represent the range of the vertical scrollbar. This corresponds to the length of the content
             * in the view.
             * 2. Let "E" represent the extent of the vertical scrollbar. The extent is a constant value and is
             * (probably) equal to a value proportional to the height of the view.
             * 3. Offset "o" represents the current position in the range that is visible to the user. It can take
             * values from "0 to E".
             *
             * Now the DistanceToEnd is calculated using these three values as follows :
             *
             * DistanceToEnd = (R - o) / E
             *
             * DistanceToEnd will hold the value in NumberOfScreenToEnd units.
             *
             */

            float distanceToEnd =
                    ((float)(verticalScrollRange - verticalScrollOffset))/((float)(verticalScrollExtent));

            if(prevDistanceToEnd == -1) {
                 prevDistanceToEnd = distanceToEnd;
            } else {
                 if(listener != null) {
                     if(distanceToEnd > prevDistanceToEnd) {
                        // User is scrolling up
                         listener.onScrollingUp();
                     } else {
                        // User is scrolling up
                         listener.onScrollingDown();
                    }
                 }
                 prevDistanceToEnd = distanceToEnd;
            }

            if(isScrollable == null) {
                // Check if the view height is less than a screen (i.e., no scrolling is enabled)
                if((horizontalScrollBarHeight + verticalScrollExtent) >= verticalScrollRange) {
                    isScrollable = Boolean.FALSE;
                } else {
                    isScrollable = Boolean.TRUE;
                }
            }

        }

    }

    public interface ScrollDirectionListener {

        public void onScrollingUp();

        public void onScrollingDown();

    }

}

The idea is to calculate the distanceToEnd. If distanceToEnd increases, the user is scrolling up and if it decreases, the user is scrolling down. That will also give you the exact distance to the end of the list.

If you are just trying to know whether the user is scrolling up or down you can override the onInterceptTouchEvent to detect the scrolling direction like below :

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mInitialX = event.getX();
                mInitialY = event.getY();
                return true;
            case MotionEvent.ACTION_MOVE:
                final float x = event.getX();
                final float y = event.getY();
                final float yDiff = y - mInitialY; // yDiff less than 0.0 implies scrolling down while yDiff greater than 0.0 implies scrolling up. If I try to add the less than or greater than symbols, the preview refuses to display it.
                if(yDiff less than 0.0) listener.onScrollingDown();
                else if(yDiff greater than 0.0) listener.onScrollingUp();
                break;
        }
        return super.onInterceptTouchEvent(event);
    }

Spiroid

Answer 13

Trick about detect scroll up or down in listview, you just call this function on onScroll function in OnScrollListener of ListView.

private int oldFirstVisibleItem = -1;
    private protected int oldTop = -1;
    // you can change this value (pixel)
    private static final int MAX_SCROLL_DIFF = 5;

    private void calculateListScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        if (firstVisibleItem == oldFirstVisibleItem) {
            int top = view.getChildAt(0).getTop();
            // range between new top and old top must greater than MAX_SCROLL_DIFF
            if (top > oldTop && Math.abs(top - oldTop) > MAX_SCROLL_DIFF) {
                // scroll up
            } else if (top < oldTop && Math.abs(top - oldTop) > MAX_SCROLL_DIFF) {
                // scroll down
            }
            oldTop = top;
        } else {
            View child = view.getChildAt(0);
            if (child != null) {
                oldFirstVisibleItem = firstVisibleItem;
                oldTop = child.getTop();
            }
        }
    }

Supermundane

Answer 14

Simple way to detect scroll up/down on android listview

@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount){
  if(prevVisibleItem != firstVisibleItem){
    if(prevVisibleItem < firstVisibleItem)
      //ScrollDown
    else
      //ScrollUp

  prevVisibleItem = firstVisibleItem;
}

dont forget

yourListView.setOnScrollListener(yourScrollListener);

Piassava

Answer 15

Simple way to load more items on scroll up/down event in android GridView

    grid.setOnScrollListener(new AbsListView.OnScrollListener() {
                private int mLastFirstVisibleItem;
                @Override
                public void onScrollStateChanged(AbsListView view, int scrollState) {
                    // TODO Auto-generated method stub
                    Log.d("state",String.valueOf(scrollState));


                    if(scrollState == 0)
                        Log.i("a", "scrolling stopped...");


                    if (view.getId() == grid.getId()) {

                        final int currentFirstVisibleItem = grid.getLastVisiblePosition();
                        mLastFirstVisibleItem = grid.getFirstVisiblePosition();

                        if (currentFirstVisibleItem > mLastFirstVisibleItem) {
                            mIsScrollingUp = false;
                            if(!next.contains("null")){

                           //Call api to get products from server

                             }


                            Log.i("a", "scrolling down...");
                        } else if (currentFirstVisibleItem < mLastFirstVisibleItem) {
                            mIsScrollingUp = true;
                            Log.i("a", "scrolling up...");
                        }

                        mLastFirstVisibleItem = currentFirstVisibleItem;
                    }

                }
            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                Log.d("on scroll","");
            }
        });

Alcatraz

Answer 16

Here's what I would try first:

1) Create an interface (let's call it OnScrollTopOrBottomListener) with these methods:

void onScrollTop();

void onScrollBottom();

2) In your list's adapter, add a member instance, typed as the interface you created and supply a setter and getter.

3) In the getView() implementation of your adapter, check if the position parameter is either 0 or getCount() - 1. Also check that your OnScrollTopOrBottomListener instance is not null.

4) If the position is 0, call onScrollTopOrBottomListener.onScrollTop(). If position is getCount() - 1, call onScrollTopOrBottomListener.onScrollBottom().

5) In your OnScrollTopOrBottomListener implementation, call the appropriate methods to get the desired data.

Hope that helps in some way.

-Brandon

Coparcener

Answer 17

I have encountered problems using some example where the cell size of ListView is great. So I have found a solution to my problem which detects the slightest movement of your finger . I've simplified to the minimum possible and is as follows:

private int oldScrolly;


@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {

}

@Override
public void onScroll(AbsListView view, int firstVisibleItem, int    visibleItemCount, int totalItemCount) {

            View view = absListView.getChildAt(0);
            int scrolly = (view == null) ? 0 : -view.getTop() + absListView.getFirstVisiblePosition() * view.getHeight();
            int margin = 10;

            Log.e(TAG, "Scroll y: " + scrolly + " - Item: " + firstVisibleItem);


            if (scrolly > oldScrolly + margin) {
                Log.d(TAG, "SCROLL_UP");
                oldScrolly = scrolly;
            } else if (scrolly < oldScrolly - margin) {
                Log.d(TAG, "SCROLL_DOWN");
                oldScrolly = scrolly;
            }
        }
    });

PD: I use the MARGIN to not detect the scroll until you meet that margin . This avoids problems when I show or hide views and avoid blinking of them.

Richman