如何检查数据更新后ListView是否更改

Question

I have one unsolved question, which I couldn't accomplish to answer myself. Is there any way, how to check, if the ListView ( ListView.getCount(); ) changed after updating the data - more accurately, after load-more process. I want to remove the footer view ( ProgressBar ) after the ListView stays the same after my update method.

Is there any way how to do it?

If necessary, check short codes below

Thanks in advance!

My method, which adds more data:

public void updateData() {
    mListView = (ListView)getView().findViewById(R.id.animal_list);     
    final ParseQuery<Animal> query = ParseQuery.getQuery(Animal.class);
    query.setCachePolicy(CachePolicy.NETWORK_ONLY);
    query.orderByAscending("animal");
    query.setLimit(mListView.getCount() + 5);

    Log.v("updateData", "uploading data from Parse.com");
    query.findInBackground(new FindCallback<Animal>() {

        @Override
        public void done(List<Animal> animals, ParseException error) {

            if(animals != null){
                mAdapter.clear();
                mProgressBar = (ProgressBar) getView().findViewById (R.id.loading_animals);
                mProgressBar.setVisibility(View.INVISIBLE);
                RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);  
                footie.setVisibility(View.VISIBLE);

                mAdapter.clear();

                for (int i = 0; i < animals.size(); i++) {

                    mAdapter.add(animals.get(i));

                }  

            }  
        }
    }); 
}

My OnScrollListener, which finds out, that the data have to be updated:

mListView.setOnScrollListener(new OnScrollListener() {

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


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

        int threshold = 1;
        int count = mListView.getCount();

        if (scrollState == SCROLL_STATE_IDLE) {
            if (mListView.getLastVisiblePosition() >= count - threshold){

                updateData();
                //here do I need to add - if ListView didnt change - > remove footer                        
            }

        }
        if (SCROLL_STATE_TOUCH_SCROLL == scrollState) {
            View currentFocus = getActivity().getCurrentFocus();

            if(currentFocus != null) {
                currentFocus.clearFocus();
            }
        }
    } 
});

Answer 1

You can extend the adapter and set the data separately.

public void updateData() {
    ...

    query.findInBackground(new FindCallback<Animal>() {
        @Override
        public void done(List<Animal> animals, ParseException error) {

            if(animals != null){
                mProgressBar = (ProgressBar) getView().findViewById (R.id.loading_animals);
                mProgressBar.setVisibility(View.INVISIBLE);
                RelativeLayout footie = (RelativeLayout) getView().findViewById(R.id.footerview);  
                footie.setVisibility(View.VISIBLE);

                mAdapter.setItems(animals);
            }  
        }
    }); 
}

class CustomAdapter extends ArrayAdapter {
    public void setItems(List<Animal> animals) {
        int oldCount = getCount();
        int newCount = animals.size();
        clear();
        addAll(animals);
        if (oldCount != newCount) {
            // Do whatever you want here. The number of items changed.
        }
    }
}