Checking if Android Gridview is scrolled to its top

Question

I want to determine if my Gridview is scrolled to its top.

Right now I'm using getChildAt(0).getTop() to do this. I save the value of getChildAt(0).getTop() on first draw and compare to getChildAt(0).getTop() on subsequent draws .

However, this seems hacky and seems to sometimes give me incorrect results.

Any better ideas?

score 1 · Answer 1 · answered Mar 14 '13 at 00:39

1

Try using the onScrollListener

setOnScrollListener(this);

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

    if(firstVisibleItem == 0){
        //do stuff here
    }

}

answered Mar 14 '13 at 00:39

JackMahoney

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If the first item is visible it doesn't mean GridView is scrolled to top. – May 19 '15 at 07:31

score 0 · Answer 2 · answered Jul 14 '12 at 19:25

0

The getChildAt(0) returns you the first visible item of the GridView and I guess that it's not what you want.

If you use yourGridView.getFirstVisiblePosition() method it will return the first visible position your data adapter, and that is what you want.

answered Jul 14 '12 at 19:25

yugidroid

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Hmm. I don't see how yourGridView.getFirstVisiblePosition() gives me what I want, unless I'm misunderstanding "visible." If the second row is the first row visible, I want the overall method I'm trying to write -- isGridScrolledToTop() -- to return false. It should return false in this case the grid isn't scrolled to its top. (It's scrolled to the second row.) – user1435114 Jul 16 '12 at 14:54
this isn't very accurate i find. – JMRboosties Jan 30 '14 at 18:56

score 0 · Answer 3 · answered May 07 '14 at 05:37

Hope this can help, it works for me, good luck.

yourGridView.setOnScrollListener(new OnScrollListener() { @Override public void onScrollStateChanged(AbsListView view, int scrollState) { if(SCROLL_STATE_IDLE == scrollState) { View view = view.getChildAt(0); if(view != null) { float y = view.getY(); Log.d("Tag", "first view Y is " + y); if(y == 0) { // do what you want } } } }

score 0 · Answer 4 · answered Mar 16 '16 at 05:28

This's my answer:

mLayoutManager = new GridLayoutManager(getActivity(), 2);
mListRV= (RecyclerView).findViewById(R.id.list_rv);
mListRV.setLayoutManager(mLayoutManager);

mListRV.setOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                    if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                        View v = mLayoutManager.getChildAt(0);
                        int offsetTop = v.getTop();
                        int offsetBottom = v.getBottom();
                        int height = (offsetBottom - offsetTop);
                        if(offsetTop >= -height/2) {
                            mListRV.smoothScrollBy(0, offsetTop);
                        } else {
                            mListRV.smoothScrollBy(0, height + offsetTop);
                        }
                    } 
                }
            });

Checking if Android Gridview is scrolled to its top

4 Answers4