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我有一個recyclerView，其中包含onCreate中流行的電影。我通過按下選項菜單爲新數據集（頂級電影）發送新的獲取請求，並且使用新數據記錄正確的數據，從而實現了它的工作。數據返回後，我確保將全局arrayList變量設置爲返回數據集的變量。但問題是，我調用「setupAdapter（）」方法後，我的視圖沒有更新，該方法接受mItems（全局arrayList變量應該已被設置爲新的數據集）的參數。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();
}
}
這是setUpAdapter方法：
private void setupAdapter() {
if (isAdded()) {
mPhotoRecyclerView.setAdapter(new PhotoAdapter(mItems));
}
}
而這正是我有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;
這是完整的代碼
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();
}
}
}
感謝您的幫助。當我嘗試你的代碼時，它不會在onCreate的視圖中加載任何內容，但它會記錄所有正確的數據。當我選擇「評分最高的」電影選項菜單時，它會加載正確的數據並記錄下來，但不會顯示在視圖中。 –
請替換代碼「mPhotoRecyclerView.setAdapter（new PhotoAdapter（mItems））;」通過「adaptor.notifyDataSetChanged（）;」 （所有使用該行的地方） – Sabari
並且請確保setupAdaptor（）中的行「adaptor.notifyDataSetChanged（）;」正在執行或不執行。也許「if（isAdded（））」返回false – Sabari