如何解决从房间数据库中删除后重新打开活动时，回收者视图仅更新
我有一个带有Recycler视图的片段，该视图显示了Room数据库中的内容。在我的适配器中，我有一个ImageButton，单击该按钮可将其从列表中删除。我可以确认该项目已从数据库中删除，但是我的列表没有预期的行为。为了对其进行更新，我必须再次打开活动。
回收站视图
public class WishlistFragment extends Fragment {
private static WishlistAdapter mAdapter;
private RecyclerView mRecyclerView;
protected static List<String> wishlist;
private Context context;
protected static OnRestaurantClickedListener listener;
private FirebaseAuth mAuth;
public static WishlistAdapter getmAdapter() {
return mAdapter;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
context = getContext();
mAuth = FirebaseAuth.getInstance();
wishlist = new ArrayList<>();
mAdapter = new WishlistAdapter(context,wishlist,getActivity(),mAuth.getCurrentUser().getUid());
LoadWishlistTask lwt=new LoadWishlistTask(getActivity(),mAdapter,mAuth.getCurrentUser().getUid());
lwt.execute();
}
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {
View mContentView = inflater.inflate(R.layout.restaurants_list,container,false);
mRecyclerView = mContentView.findViewById(R.id.recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(mContentView.getContext()));
mRecyclerView.setAdapter(mAdapter);
RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(context,DividerItemDecoration.VERTICAL);
mRecyclerView.addItemDecoration(itemDecoration);
return mContentView;
}
@Override
public void onResume() {
super.onResume();
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
listener = (OnRestaurantClickedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnRestaurantClickedClicked");
}
}
}
适配器
public class WishlistAdapter extends RecyclerView.Adapter<WishlistAdapter.WishlistViewHolder> {
private Context mContext;
private List<String> mRestaurantIds;
private Activity act;
private String currentUserId;
public WishlistAdapter(Context context,List<String> ids,Activity activity,String currentUser) {
mRestaurantIds=ids;
mContext = context;
act=activity;
currentUserId=currentUser;
}
@Override
public WishlistViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
// Get layout inflater from context
Context context = parent.getContext();
LayoutInflater inflater = LayoutInflater.from(context);
// Inflate layout
View rView = inflater.inflate(R.layout.item_restaurant,parent,false);
// Return a new holder instance
return new WishlistViewHolder(rView);
}
@Override
public void onBindViewHolder(final WishlistViewHolder viewHolder,final int position) {
// Get the data model based on position
final String id = mRestaurantIds.get(position);
getApi().getRestaurantDetails(Integer.parseInt(id),"75be9f9e2239fe637bf9cb1b46979d91")
.enqueue(new Callback<Restaurant_>() {
@Override
public void onResponse(Call<Restaurant_> call,Response<Restaurant_> response) {
final TextView name=viewHolder.nameTextView;
name.setText(response.body().getName());
final TextView rating=viewHolder.ratingTextView;
rating.setText(response.body().getUserRating().getAggregateRating());
final ImageButton remove=viewHolder.removeButton;
remove.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Wishlist deletedRestaurant=new Wishlist(currentUserId,id);
RemoveWLTask rt=new RemoveWLTask(deletedRestaurant,act,WishlistFragment.wishlist);
rt.execute();
}
});
viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
WishlistFragment.listener.onRestaurantClicked(id);
}
});
}
@Override
public void onFailure(Call<Restaurant_> call,Throwable t) {
AlertDialog.Builder builder = new AlertDialog.Builder(act);
builder.setMessage("Couldn´t load restaurant details");
AlertDialog mDialog = builder.create();
mDialog.show();
}
});
}
@Override
public int getItemCount() {
return mRestaurantIds.size();
}
private Retrofit getRetrofit() {
return new Retrofit.Builder()
.baseUrl("https://developers.zomato.com/api/v2.1/")
.addConverterFactory(GsonConverterFactory.create())
.build();
}
private ZomatoApi getApi() {
return getRetrofit().create(ZomatoApi.class);
}
public class WishlistViewHolder extends RecyclerView.ViewHolder {
public TextView nameTextView;
public TextView ratingTextView;
public TextView distanceTextView;
public ImageButton removeButton;
public WishlistViewHolder(View itemView) {
super(itemView);
nameTextView = itemView.findViewById(R.id.restaurantName);
ratingTextView=itemView.findViewById(R.id.restaurantRating);
distanceTextView=itemView.findViewById(R.id.restaurantDistance);
removeButton=itemView.findViewById(R.id.wishlistButton);
}
}
}
删除任务
public class RemoveWLTask extends AsyncTask<Void,Void,Void> {
private Wishlist deletedRestaurant;
private DB db;
private Activity activity;
private List<String> wishlist;
public RemoveWLTask (Wishlist deletedRestaurant,List<String> wishlist) {
this.deletedRestaurant=deletedRestaurant;
this.activity=activity;
this.db= Room.databaseBuilder(activity.getApplicationContext(),DB.class,"sample-db").build();
this.wishlist=wishlist;
}
@Override
protected Void doInBackground(Void... voids) {
while (!isCancelled()){
db.daoAcess().deleteFromWishlist(deletedRestaurant);
break;
}
return null;
}
@Override
protected void onPostExecute (Void aVoid) {
int index = wishlist.indexOf(deletedRestaurant);
wishlist.remove(deletedRestaurant);
WishlistFragment.getmAdapter().notifyItemRemoved(index);
WishlistFragment.getmAdapter().notifyItemRangeChanged(index,wishlist.size());
}
}
解决方法
发现错误，我需要传递DeletedRestaurant.getRestaurantId（）作为参数，而不是DeletedRestaurant
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