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我有一个recyclerView，其中包含onCreate中流行的电影。我通过按下选项菜单为新数据集（顶级电影）发送新的获取请求，并且使用新数据记录正确的数据，从而实现了它的工作。数据返回后，我确保将全局arrayList变量设置为返回数据集的变量。但问题是，我调用“setupAdapter（）”方法后，我的视图没有更新，该方法接受mItems（全局arrayList变量应该已被设置为新的数据集）的参数。正在更新RecyclerView
public class FetchItemsTask extends AsyncTask<Void,Void,List<MovieItem>> {
private String mQuery;
public FetchItemsTask(String query) {
mQuery = query;
}
@Override
protected List<MovieItem> doInBackground(Void... params) {
return new MovieFetchr().fetchItems(mQuery);
}
@Override
protected void onPostExecute(List<MovieItem> items) {
mItems = items;
for (int i = 0; i < mItems.size(); i++) {
Log.i("MovieInGalleryFragment", mItems.get(i).getCaption());
}
setupAdapter();
}
}
这是setUpAdapter方法：
private void setupAdapter() {
if (isAdded()) {
mPhotoRecyclerView.setAdapter(new PhotoAdapter(mItems));
}
}
而这正是我有mItems：
public class PhotoGalleryFragment extends Fragment {
private static final String TAG = "PhotoGalleryFragment";
private RecyclerView mPhotoRecyclerView;
private List<MovieItem> mItems = new ArrayList<>();
private ThumbnailDownloader<PhotoHolder> mThumbnailDownloader;
这是完整的代码
public class PhotoGalleryFragment extends Fragment {
private static final String TAG = "PhotoGalleryFragment";
private RecyclerView mPhotoRecyclerView;
private List<MovieItem> mItems = new ArrayList<>();
private ThumbnailDownloader<PhotoHolder> mThumbnailDownloader;
public static PhotoGalleryFragment newInstance() {
return new PhotoGalleryFragment();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
updateItems("popular");
Handler responseHandler = new Handler();
mThumbnailDownloader = new ThumbnailDownloader<>(responseHandler);
mThumbnailDownloader.setThumbnailDownloadListener(
new ThumbnailDownloader.ThumbnailDownloadListener<PhotoHolder>() {
@Override
public void onThumbnailDownloaded(PhotoHolder photoHolder, Bitmap bitmap) {
Drawable drawable = new BitmapDrawable(getResources(), bitmap);
photoHolder.bindDrawable(drawable);
}
}
);
mThumbnailDownloader.start();;
mThumbnailDownloader.getLooper();
Log.i(TAG, "Background thread started");
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_photo_gallery, container, false);
mPhotoRecyclerView = (RecyclerView) v
.findViewById(R.id.fragment_photo_gallery_recycler_view);
mPhotoRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 5));
setupAdapter();
return v;
}
@Override
public void onDestroyView() {
super.onDestroyView();
mThumbnailDownloader.clearQueue();
}
@Override
public void onDestroy() {
super.onDestroy();
mThumbnailDownloader.quit();
Log.i(TAG, "Background thread destroyed");
}
private void setupAdapter() {
if (isAdded()) {
mPhotoRecyclerView.setAdapter(new PhotoAdapter(mItems));
}
}
void updateItems(String query){
mItems.clear();
new FetchItemsTask(query).execute();
mPhotoRecyclerView.getAdapter().notifyDataSetChanged();
}
private class PhotoHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private ImageView mItemImageView;
private MovieItem mMovieItem;
public PhotoHolder(View itemView) {
super(itemView);
mItemImageView = (ImageView) itemView
.findViewById(R.id.fragment_photo_gallery_image_view);
itemView.setOnClickListener(this);
}
public void bindDrawable(Drawable drawable) {
mItemImageView.setImageDrawable(drawable);
}
public void bindMovieItem(MovieItem movieItem){
mMovieItem = movieItem;
}
@Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), ViewPhotoDetailsActivity.class);
intent.putExtra("Movie Title", mMovieItem.getCaption());
intent.putExtra("Movie Poster", mMovieItem.getUrl());
intent.putExtra("Movie Plot", mMovieItem.getPlot());
intent.putExtra("Movie Rating", mMovieItem.getRating());
intent.putExtra("Release Date", mMovieItem.getRelease_date());
startActivity(intent);
}
}
private class PhotoAdapter extends RecyclerView.Adapter<PhotoHolder> {
private List<MovieItem> mMovieItems;
public PhotoAdapter(List<MovieItem> movieItems) {
mMovieItems = movieItems;
}
@Override
public PhotoHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
LayoutInflater inflater = LayoutInflater.from(getActivity());
View view = inflater.inflate(R.layout.list_item_gallery, viewGroup, false);
return new PhotoHolder(view);
}
@Override
public void onBindViewHolder(PhotoHolder photoHolder, int position) {
MovieItem movieItem = mMovieItems.get(position);
photoHolder.bindMovieItem(movieItem);
Drawable placeholder = getResources().getDrawable(R.drawable.bill_up_close);
photoHolder.bindDrawable(placeholder);
mThumbnailDownloader.queueThumbnail(photoHolder, movieItem.getUrl());
}
@Override
public int getItemCount() {
return mMovieItems.size();
}
}
public class FetchItemsTask extends AsyncTask<Void,Void,List<MovieItem>> {
private String mQuery;
public FetchItemsTask(String query) {
mQuery = query;
}
@Override
protected List<MovieItem> doInBackground(Void... params) {
return new MovieFetchr().fetchItems(mQuery);
}
@Override
protected void onPostExecute(List<MovieItem> items) {
mItems = items;
for (int i = 0; i < mItems.size(); i++) {
Log.i("MovieInGalleryFragment", mItems.get(i).getCaption());
}
setupAdapter();
}
}
}
感谢您的帮助。当我尝试你的代码时，它不会在onCreate的视图中加载任何内容，但它会记录所有正确的数据。当我选择“评分最高的”电影选项菜单时，它会加载正确的数据并记录下来，但不会显示在视图中。 –
请替换代码“mPhotoRecyclerView.setAdapter（new PhotoAdapter（mItems））;”通过“adaptor.notifyDataSetChanged（）;” （所有使用该行的地方） – Sabari
并且请确保setupAdaptor（）中的行“adaptor.notifyDataSetChanged（）;”正在执行或不执行。也许“if（isAdded（））”返回false – Sabari