我指的是本教程==> https://uniqueandrocode.com/add-to-favourites-and-display-favourites-in-recyclerview/在我的项目中我有底部导航...我正在尝试添加收藏夹第一个选项卡并在底部导航栏的第二个选项卡中显示收藏夹。我正在使用 Room 库。
当活动加载时，收藏夹最初都是空白的，但是当我第一行作为收藏夹和转到收藏夹选项卡时，它会正确显示，但是当我回到第一个选项卡时，它会自动填充所有收藏夹图标（我还没有这样做）只做了第一行）
真的需要帮助。提前致谢。
道：
@Dao
public interface FavoriteDao {
@Insert
public void addData(FavoriteList favoriteList);
@Query("select * from favoritelist")
public List<FavoriteList> getFavoriteData();
@Query("SELECT EXISTS (SELECT 1 FROM favoritelist WHERE id=:id)")
public int isFavorite(int id);
@Delete
public void delete(FavoriteList favoriteList);
}
数据库：
@Database(entities={FavoriteList.class},version = 1)
public abstract class FavoriteDatabase extends RoomDatabase {
public abstract FavoriteDao favoriteDao();
}
收藏列表：
@Entity(tableName="favoritelist")
public class FavoriteList {
@PrimaryKey
private int id;
@ColumnInfo(name = "source")
private String source;
@ColumnInfo(name = "author")
private String author;
@ColumnInfo(name = "title")
private String title;
@ColumnInfo(name = "description")
private String description;
@ColumnInfo(name = "url")
private String url;
@ColumnInfo(name = "urlToImage")
private String urlToImage;
@ColumnInfo(name = "publishedAt")
private String publishedAt;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getSource() {
return source;
}
public void setSource(String source) {
this.source = source;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUrlToImage() {
return urlToImage;
}
public void setUrlToImage(String urlToImage) {
this.urlToImage = urlToImage;
}
public String getPublishedAt() {
return publishedAt;
}
public void setPublishedAt(String publishedAt) {
this.publishedAt = publishedAt;
}
}
新闻片段：
public class news extends Fragment {
ImageView favbtn;
RecyclerView recyclerView;
SwipeRefreshLayout swipeRefreshLayout;
EditText etQuery;
Button btnSearch;
Adapter adapter;
List<Articles> articles = new ArrayList<>();
public static FavoriteDatabase favoriteDatabase;
public news() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_news, container, false);
swipeRefreshLayout = view.findViewById(R.id.swiprefresh);
etQuery = view.findViewById(R.id.etQuery);
btnSearch = view.findViewById(R.id.btnSearch);
favoriteDatabase= Room.databaseBuilder(getActivity(),FavoriteDatabase.class,"myfavdb").
allowMainThreadQueries().build();
recyclerView = view.findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
final String country = getCountry();
retrieveJson("", country, API_Key);
btnSearch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (!etQuery.getText().toString().equals("")) {
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
retrieveJson(etQuery.getText().toString(), country, API_Key);
}
});
retrieveJson(etQuery.getText().toString(), country, API_Key);
} else {
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
retrieveJson("", country, API_Key);
}
});
retrieveJson("", country, API_Key);
}
}
});
return view;
}
private void showChangeLanguageDialog() {
}
public void retrieveJson(String query, String country, String apiKey) {
swipeRefreshLayout.setRefreshing(true);
Call<Headlines> call;
if (!etQuery.getText().toString().equals("")) {
call = ApiClient.getInstance().getApi().getSpecifiedData(query, apiKey);
} else {
call = ApiClient.getInstance().getApi().getHeadLines(country, apiKey);
}
call.enqueue(new Callback<Headlines>() {
@Override
public void onResponse(Call<Headlines> call, Response<Headlines> response) {
if (response.isSuccessful() && response.body().getArticles() != null) {
swipeRefreshLayout.setRefreshing(false);
// articles.clear();
articles = response.body().getArticles();
adapter = new Adapter(getContext(), articles);
recyclerView.setAdapter(adapter);
}
}
@Override
public void onFailure(Call<Headlines> call, Throwable t) {
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(getContext(), t.getLocalizedMessage(), Toast.LENGTH_SHORT).show();
}
});
}
public String getCountry() {
Locale locale = Locale.getDefault();
String country = locale.getCountry();
return country.toLowerCase();
}
}
适配器：
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
Context context;
List<Articles> articles;
public Adapter(Context context, List<Articles> articles) {
this.context = context;
this.articles = articles;
}
@NonNull
@Override
public Adapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final Adapter.ViewHolder holder, final int position) {
final Articles a = articles.get(position);
String imageUrl = a.getUrlToImage();
String url = a.getUrl();
holder.tvTitle.setText(a.getTitle());
Picasso.get().load(imageUrl).into(holder.imageView);
holder.tvSource.setText(a.getSource().getName());
holder.tvDate.setText(dateTime(a.getPublishedAt()));
holder.cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context,DetailedActivity.class);
intent.putExtra("title",a.getTitle());
intent.putExtra("source",a.getSource().getName());
intent.putExtra("time",dateTime(a.getPublishedAt()));
intent.putExtra("desc",a.getDescription());
intent.putExtra("imageUrl",a.getUrlToImage());
intent.putExtra("url",a.getUrl());
context.startActivity(intent);
}
});
if (news.favoriteDatabase.favoriteDao().isFavorite(articles.get(position).getId())==1)
holder.bookmark.setImageResource(R.drawable.ic_bookmark);
else
holder.bookmark.setImageResource(R.drawable.ic_baseline_bookmark_border_24);
holder.bookmark.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FavoriteList favoriteList = new FavoriteList();
int id = articles.get(position).getId();
String source = articles.get(position).getSource().getName();
String author = articles.get(position).getAuthor();
String publishedAt = articles.get(position).getPublishedAt();
String description = articles.get(position).getDescription();
String title = articles.get(position).getTitle();
String url = articles.get(position).getUrl();
String urlToImage = articles.get(position).getUrlToImage();
favoriteList.setId(id);
favoriteList.setAuthor(author);
favoriteList.setDescription(description);
favoriteList.setSource(source);
favoriteList.setPublishedAt(publishedAt);
favoriteList.setTitle(title);
favoriteList.setUrl(url);
favoriteList.setUrlToImage(urlToImage);
favoriteList.setPublishedAt(dateTime(articles.get(position).getPublishedAt()));
if (news.favoriteDatabase.favoriteDao().isFavorite(id)!=1){
holder.bookmark.setImageResource(R.drawable.ic_bookmark);
news.favoriteDatabase.favoriteDao().addData(favoriteList);
}else {
holder.bookmark.setImageResource(R.drawable.ic_baseline_bookmark_border_24);
news.favoriteDatabase.favoriteDao().delete(favoriteList);
}
}
});
}
@Override
public int getItemCount() {
return articles.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView tvTitle, tvSource, tvDate;
ImageView imageView;
ImageButton bookmark;
CardView cardView;
public ViewHolder(@NonNull View itemView) {
super(itemView);
tvTitle = itemView.findViewById(R.id.tvId);
tvSource = itemView.findViewById(R.id.tvSource);
tvDate = itemView.findViewById(R.id.tvDate);
imageView = itemView.findViewById(R.id.image);
cardView = itemView.findViewById(R.id.cardView);
bookmark = itemView.findViewById(R.id.favrr);
}
}