未调用OnScrollChangedState

Question

我有一个实现OnScrollListener的ArrayAdapter。 OnScroll方法被调用很多次，大多数情况下不止一次。现在永远不会调用OnScrollChangedState，我完全不知道为什么不。当他被称为后来的时候我读了，我没有得到这种行为。这是我的代码

@Override
public void onActivityCreated(Bundle savedInstanceState){
    super.onActivityCreated(savedInstanceState);
   /*   Some code    */
  setNewListAdapter()
  getListView().setOnScrollListener(movieListAdapter);



}     








public class MovieListAdapter extends ArrayAdapter<Movie> implements AbsListView.OnScrollListener{

    private ImageView thumbnail;
    private TextView title;
    private RatingBar ratingBar;
    private int currentFirstVisibleItem;
    private int currentVisibleItemCount;
    private int currentScrollState;
    private int totalItemCount;


    public MovieListAdapter(Context context, ArrayList<Movie> movies) {
        super(context, 0, movies);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // Get the data item for this position
        Movie movie = getItem(position);
        // Check if an existing view is being reused, otherwise inflate the view
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.movie_list, parent, false);
        }
        // Lookup view
        thumbnail = (ImageView) convertView.findViewById(R.id.film_cover);
        title = (TextView) convertView.findViewById(R.id.movieTitle);
        ratingBar = (RatingBar) convertView.findViewById(R.id.ratingBar);
        // Populate the views
        new ImageLoader(movie.getPoster_path(),thumbnail).execute();
        title.setText(movie.getTitle());
        ratingBar.setRating((float)movie.getVote_average());

        // Return the completed view to render on screen
        return convertView;
    }

    private void updateData(){

        this.clear();

        for(Movie m : movieArrayList){
            this.insert(m,this.getCount());
        }
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        this.currentScrollState = scrollState;
        this.isScrollCompleted();
    }

    /* Detect if the scroll has been completed*/
    private void isScrollCompleted() {

        final int lastItem = currentFirstVisibleItem + currentVisibleItemCount;

        if (this.currentScrollState == SCROLL_STATE_IDLE && lastItem == totalItemCount) {
            listener.nextPage(++currentPage);
            updateData(); // Refresh Movies List
        } else if (this.currentScrollState == SCROLL_STATE_IDLE && (currentFirstVisibleItem + totalItemCount == totalItemCount)) {
            listener.previousPage(--currentPage);
            updateData(); // Refresh Movies List
        }

    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        this.currentFirstVisibleItem = firstVisibleItem;
        this.currentVisibleItemCount = visibleItemCount;
        this.totalItemCount = totalItemCount;
    }
}

先谢谢你们。任何反馈都表示赞赏

Answer 1

我猜你在这里犯了一个逻辑错误，你可以尝试更换如下并检查它是否有效吗？

lastItem == totalItemCount

到

lastItem == totalItemCount - 1

并且同样替换

currentFirstVisibleItem + totalItemCount == totalItemCount

到

currentFirstVisibleItem + totalItemCount == totalItemCount - 1