Detect setOnScrollListener in Listview properly after setting Listview height dynamically

Question

I am using listview inside Viewpager where I need to set ListView height based on child and I need to add new Items when user scroll to last position of Listview. But the problem is when I am setting listview height dynamically its making current listview item visible(or selected). That's why getting (calling method to get data) automatically. Code is given below:

int index = lvNetwork.getFirstVisiblePosition();
    View v = lvNetwork.getChildAt(0);
    int top = (v == null) ? 0 : v.getTop();

    adapter = new NetworkAdapter(activity, R.layout.network_custom_row, networkDataArrayList);
    adapter.notifyDataSetChanged();
    lvNetwork.setAdapter(adapter);
    Utils.setlistViewHeight(lvNetwork, activity);

    lvNetwork.setSelectionFromTop(index, top);

    lvNetwork.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

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

            int finalItem = firstVisibleItem + visibleItemCount;

            Log.d("dataCalling", "visible " + finalItem);
            Log.d("dataCalling", "total " + totalItemCount);

            if (finalItem == totalItemCount) {

                if (preLast != finalItem) {
                    preLast = finalItem;
                    Log.d("dataCalling", String.valueOf(totalItemCount));
                    Log.d("dataCalling", "Page " + nextid);
                    progressBar.setVisibility(View.VISIBLE);

                      getNetworkFeed();

                }
            }
        }
    });

setlistviewHeight method inside Utils,

public static void setlistViewHeight(ListView listView, Context context) {

    ListAdapter myListAdapter = listView.getAdapter();

    if (myListAdapter == null) {
        return;
    }

    int totalHeight = 0;
    for (int size = 0; size < myListAdapter.getCount(); size++) {

        View listItem = myListAdapter.getView(size, null, listView);
        if (listItem instanceof ViewGroup)
            listItem.setLayoutParams(new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.WRAP_CONTENT,
                    RelativeLayout.LayoutParams.WRAP_CONTENT));

        WindowManager wm = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        @SuppressWarnings("deprecation")
        int screenWidth = display.getWidth();
        int listViewWidth = screenWidth - 65;
        int widthSpec = View.MeasureSpec.makeMeasureSpec(listViewWidth,
                View.MeasureSpec.AT_MOST);
        listItem.measure(widthSpec, 0);

        totalHeight += listItem.getMeasuredHeight();
    }

    ViewGroup.LayoutParams params = listView.getLayoutParams();
    params.height = totalHeight
            + (listView.getDividerHeight() * (myListAdapter.getCount()));
    listView.setLayoutParams(params);
    listView.requestLayout();
}

***This code works good if I do not need to set listview height dynamically. What should I change here to make it work or any alternative solution to get desire result?

Any help will be appreciated.

Answer 1

But the problem is when I am setting listview height dynamically its making current listview item visible

Setting height dynamically is not the problem. Rather, the problem is you are setting the height of the listview as the maximum possible height of listview by calculating height of each item in the list. So what will happen is all the items of the listview will be populated at once and will remain inflated in the list.(NOTE : No view recycling will happen now)

That's why getting (calling method to get data) automatically

The call is happening because you are setting the height of the listview based on the total number of items in the list. What happens because of this is, all the elements in your listview will be in visible state at any given point of time. Which means your condition

if (finalItem == totalItemCount){}

will always be true because your visibleItemCount will always be totalItemCount which makes your final item always equal to totalItemCount. (you can verify this by debugging your app).

What should I change here to make it work or any alternative solution to get desire result?

The best solution I can think of is setting the height of listview if and only if the total height calcuated by you on the basis of heights of all the items is lesser than the height of the screen. Otherwise, set the height of the listview as MATCH_PARENT.

ViewGroup.LayoutParams params = listView.getLayoutParams();
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        int height = size.y;
        if(totalHeight > height){
            params.height = ViewGroup.LayoutParams.MATCH_PARENT;
        }else {
            Log.d("", "");
            params.height = totalHeight
                    + (listView.getDividerHeight() * (myListAdapter.getCount()));
        }

So this code will prevent making all the views of the listview to become visible and hence onScroll visibleItemCount you will receive, will the no of items currently visible.