[英]Android Stop recycler-View adapter binding data for already shown items
我有一個應用程序使用 recyclerView 來顯示來自 Google Books API 的結果。
在每個onBindViewHolder
中,我要求客戶端給我數據,這最終導致我超過速率限制,因為每個滾動都調用數據。
假設我得到了 position 1-5 的數據,我向下滾動到 position 6-10,然后 go 回到 1-5。 我如何確保它不會再次為位置 1-5 調用客戶端,因為它已經加載了它們?
我只希望它已經調用的任何東西都留在那里。
我的適配器看起來像這樣(我刪除了一些像更多視圖這樣的部分,所以它不會混淆):
public class MyBooksAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<DiscoverBooks> discoverBooks;
private FirebaseFirestore db;
private FirebaseAuth auth;
private String UID, BookID2;
private int count, gbsSize, counter;
interface OnDiscoverBookClickListener {
void onClick(DiscoverBooks discoverBooks);
}
private OnDiscoverBookClickListener listener;
public MyBooksAdapter(int counter, List<DiscoverBooks> discoverBooks, int gbsSize, OnDiscoverBookClickListener listener) {
this.counter = counter;
this.discoverBooks = discoverBooks;
this.listener = listener;
this.gbsSize = gbsSize;
}
@Override
public int getItemViewType(int position) {
return AppConstants.IS_NOT_ADS_POSITION;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
View view;
view = LayoutInflater.from( viewGroup.getContext() ).inflate( R.layout.item_book_mybook, viewGroup, false );
return new DiscoverBooksViewHolder( view );
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
holder.setIsRecyclable( false );
if (holder instanceof DiscoverBooksViewHolder) {
((MyBooksAdapter.DiscoverBooksViewHolder) holder).bind( (discoverBooks.get( position )), holder );
}
}
@Override
public int getItemCount() {
return discoverBooks.size();
}
class DiscoverBooksViewHolder extends RecyclerView.ViewHolder {
private Button tv_Link;
private CardView cardView;
private ImageView Iv_BookCover;
private TextView tv_Author, tv_BorrowedTo, tv_BorrowedTill, tv_DateAdded, tv_Title;
private ImageButton ib_Options;
private ToggleButton tb_Status;
private DiscoverBooks discoverBooks;
private DiscoverBooksViewHolder(View itemView) {
super( itemView );
cardView = itemView.findViewById( R.id.imagecard );
Iv_BookCover = itemView.findViewById( R.id.iv_BookCover );
tv_Title = itemView.findViewById( R.id.tv_Title );
tv_Author = itemView.findViewById( R.id.tv_Author );
tv_DateAdded = itemView.findViewById( R.id.tv_DateAdded );
tv_BorrowedTo = itemView.findViewById( R.id.tv_BorrowedTo );
tv_BorrowedTill = itemView.findViewById( R.id.tv_BorrowedTill );
tv_Link = itemView.findViewById( R.id.tv_Link );
ib_Options = itemView.findViewById( R.id.ib_Options );
tb_Status = itemView.findViewById( R.id.tb_Status );
}
private void bind(DiscoverBooks discoverBooks, RecyclerView.ViewHolder viewHolder) {
this.discoverBooks = discoverBooks;
db = FirebaseFirestore.getInstance();
auth = FirebaseAuth.getInstance();
String BookID = discoverBooks.getBookID();
if (BookID.length() > AppConstants.UPLOADED_BOOK_LENGTH) {
db.collection( "Books" ).document( BookID ).get()
.addOnCompleteListener( task -> {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
DO SOMETHING
}
}
} );
} else {
//HERE I CALL GOOGLE BOOKS API
MyBookClient.getInstance().getBooks( BookID, new JsonHttpResponseHandler() {
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
if (response != null) {
final MyBook books = MyBook.fromJson( response );
//DO SOMETHING
}
}
} );
}
}
}
}
好的,我明白你的問題了。 對於每個 bookID,您從 Google 圖書中獲取其數據,現在您不想為已加載的項目點擊 api。
簡單地說,為ArrayList
創建一個全局變量為
private ArrayList<MyBook> mybooks = new ArrayList();
在onBind()
onBindViewHolder()
作為
((MyBooksAdapter.DiscoverBooksViewHolder) holder).bind(position, discoverBooks.get( position), holder);
將您的onBind()
替換為:
private void bind(int position, UserData discoverBooks, RecyclerView.ViewHolder viewHolder) {
this.discoverBooks = discoverBooks;
db = FirebaseFirestore.getInstance();
auth = FirebaseAuth.getInstance();
String BookID = discoverBooks.getBookID();
if (BookID.length() > AppConstants.UPLOADED_BOOK_LENGTH) {
db.collection("Books").document(BookID).get()
.addOnCompleteListener(task -> {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
DO SOMETHING
}
}
});
} else {
if (position >= myBooks.size() || myBooks.get(position) == null) {
//If the value doesn't exist in the ArrayList,
//it will hit the Google Books API
MyBookClient.getInstance().getBooks(BookID, new JsonHttpResponseHandler() {
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
if (response != null) {
final MyBook books = MyBook.fromJson(response);
myBooks.add(position, books);
//DO SOMETHING
}
}
});
} else {
//If the value has already been loaded in the list,
//directly use it without hitting the API
final MyBook books = myBooks.get(position);
//DO SOMETHING
}
}
}
這將解決您的問題,它將存儲已從 API 訪問的書籍,並且不會再次訪問 API 並將使用列表訪問它們。
除此之外,我建議 go 使用ViewBinding
它將您的整個DiscoverBooksViewHolder
替換為單行(在 Kotlin 中)或 2-3 行(在 Java 中),使用 viewBinding,您不必聲明和初始化視圖和可以使用Binding
直接訪問視圖,然后可以將 onBind() 從ViewHolder
中提取出來。
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