RecyclerView 刷新时重新加载相同的数据
RecyclerView reload same data when refresh
我有一个问题,当我滑动刷新数据时,第一次滑动没问题,但之后每次滑动都重新加载并一遍又一遍地添加相同的数据,到最后我有一个包含相同项目的列表以及...我正在使用装载机。
我之前尝试清除,但我不明白我的代码有什么问题,如果有人可以向我解释的话。谢谢你。
这是我的代码:
public abstract class NewsFragment extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<Articles>> {
protected ItemAdapter mArticleAdapter;
protected RecyclerView mRecyclerView;
protected NewsFragment.OnNewSelectedInterface mListener;
protected RecyclerView.LayoutManager mManager;
protected SwipeRefreshLayout mSwipeRefreshLayout;
protected LoaderManager mLoaderManager;
private boolean mStateSaved;
private static final int NEWS_LOAD_ID = 1;
public static final String KEY_LIST = "key_list";
public interface OnNewSelectedInterface {
void onListNewSelected(int index, ArrayList<Articles> articles);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.list_present_news, container, false);
mListener = (NewsFragment.OnNewSelectedInterface) getActivity();
mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipeContainer);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);
mManager = new LinearLayoutManager(getActivity());
mArticleAdapter = new ItemAdapter(getActivity(), new ArrayList<Articles>(), mListener);
mLoaderManager = getLoaderManager();
mStateSaved = mArticleAdapter.isStateSaved();
mRecyclerView.setAdapter(mArticleAdapter);
mRecyclerView.setLayoutManager(mManager);
getData();
refreshData();
if(!isNetworkAvailable())alertUserAboutError();
setDivider();
return view;
}
private void setDivider() {
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(mRecyclerView
.getContext(), DividerItemDecoration.VERTICAL);
mRecyclerView.addItemDecoration(dividerItemDecoration);
}
private void getData() {
getLoaderManager().initLoader(NEWS_LOAD_ID, null, this).forceLoad();
}
private void alertUserAboutError() {
AlertDialogFragment alertDialogFragment = new AlertDialogFragment();
alertDialogFragment.show(getActivity().getFragmentManager(), "error_dialog");
}
protected abstract String[] getUrl();
private boolean isNetworkAvailable() {
ConnectivityManager manager = (ConnectivityManager)
getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if (networkInfo != null && networkInfo.isConnected()) {
isAvailable = true;
}
return isAvailable;
}
private void refreshData() {
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
mArticleAdapter.clear();
mSwipeRefreshLayout.setRefreshing(false);
}
});
mSwipeRefreshLayout.setColorSchemeResources(
android.R.color.holo_orange_light,
android.R.color.holo_red_light);
}
@Override
public Loader<ArrayList<Articles>> onCreateLoader(int id, Bundle args) {
return new NewsLoader(getActivity(), getUrl());
}
@Override
public void onLoadFinished(Loader<ArrayList<Articles>> loader, ArrayList<Articles> data) {
if (data != null && !data.isEmpty()) {
mArticleAdapter.addAll(data);
}
}
@Override
public void onLoaderReset(Loader<ArrayList<Articles>> loader) {
mArticleAdapter.clear();
}
}
我的装载机 class:
public class NewsLoader extends AsyncTaskLoader<ArrayList<Articles>>{
private ArrayList<Articles> mArticlesArrayList;
private String[] mUrl;
public NewsLoader(Context context, String[] url) {
super(context);
mUrl = url;
}
@Override
public ArrayList<Articles> loadInBackground() {
OkHttpClient mClient = new OkHttpClient();
for (String aMUrl : mUrl) {
Request mRequest = new Request.Builder().url(aMUrl).build();
try {
Response response = mClient.newCall(mRequest).execute();
try {
if (response.isSuccessful()) {
String json = response.body().string();
getMultipleUrls(json);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return mArticlesArrayList;
}
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
private ArrayList<Articles> getArticleForecast(String jsonData) throws JSONException {
JSONObject forecast = new JSONObject(jsonData);
JSONArray articles = forecast.getJSONArray("articles");
ArrayList<Articles> listArticles = new ArrayList<>(articles.length());
for (int i = 0; i < articles.length(); i++) {
JSONObject jsonArticle = articles.getJSONObject(i);
Articles article = new Articles();
String urlImage = jsonArticle.getString("urlToImage");
article.setTitle(jsonArticle.getString("title"));
article.setDescription(jsonArticle.getString("description"));
article.setImageView(urlImage);
article.setArticleUrl(jsonArticle.getString("url"));
listArticles.add(i, article);
}
return listArticles;
}
}
我的适配器class:
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ArticleViewHolder> {
private static final String TAGO = ItemAdapter.class.getSimpleName();
private final NewsFragment.OnNewSelectedInterface mListener;
private ArrayList<Articles> mArticlesList;
private Context mContext;
private int lastPosition = -1;
private boolean mStateSaved = false;
public boolean isStateSaved() {
return mStateSaved;
}
public void setStateSaved(boolean stateSaved) {
mStateSaved = stateSaved;
}
public ItemAdapter(Context context, ArrayList<Articles> articles, NewsFragment.OnNewSelectedInterface listener){
mContext = context;
mArticlesList = articles;
mListener = listener;
}
@Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
ArticleViewHolder articleViewHolder = new ArticleViewHolder(view);
articleViewHolder.setIsRecyclable(false);
return articleViewHolder;
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(holder.getAdapterPosition()));
setAnimation(holder.itemView, holder.getAdapterPosition());
}
private void setAnimation(View viewToAnimate, int position) {
if (position > lastPosition) {
Animation animation = AnimationUtils.loadAnimation(viewToAnimate.getContext(), android.R.anim.slide_in_left);
viewToAnimate.startAnimation(animation);
lastPosition = position;
}
}
@Override
public int getItemCount() {
return mArticlesList.size();
}
public void clear() {
mArticlesList.clear();
notifyDataSetChanged();
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
protected class ArticleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
private ArticleViewHolder(View itemView) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
itemView.setOnClickListener(this);
}
private void bindArticle(final Articles article) {
Glide.with(mContext).load(article.getImageView()).into(mImageView);
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(mDescriptionTextView.getText().equals("")){
mDescriptionTextView.setVisibility(View.GONE);
}
mSaveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
insertArticle(article);
article.setStateSaved(true);
}
});
Log.v(TAGO, "Item id : " + getItemId()
+ "Item count : " + getItemCount()
+ "Item position : " + getAdapterPosition()
+ String.valueOf(article.isStateSaved()));
}
private void insertArticle(Articles articles) {
String title = articles.getTitle();
String description = articles.getDescription();
String url = articles.getArticleUrl();
ContentValues contentValues = new ContentValues();
contentValues.put(ArticleContract.ArticleEntry.COLUMN_TITLE_ARTICLE, title);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_DESCRIPTION_ARTICLE, description);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_URL_ARTICLE, url);
Uri uri = mContext.getContentResolver().insert(ArticleContract.ArticleEntry.CONTENT_URI, contentValues);
if(uri == null) {
Log.v(TAGO, "Error");
} else Toast.makeText(mContext, "Article Saved", Toast.LENGTH_SHORT).show();
}
@Override
public void onClick(View view) {
mListener.onListNewSelected(getLayoutPosition(), mArticlesList);
}
}
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(position));
setAnimation(holder.itemView, position);
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.clear();
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
如果这不起作用,那么我认为您的 api 给您提供了冗余数据。
为什么使用 articleViewHolder.setIsRecyclable(false);
另一个可能导致问题的地方是
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
您正在从一个循环中调用它,将数据添加到您的数组列表中。您的 ArrayList
中可以以某种方式插入多个数据
您使用的 ViewHolder#setIsRecyclable
不正确;此方法旨在用于防止 ViewHolder
在对其进行更改时 仅 被回收。根据文档:
Calls to setIsRecyclable()
should always be paired (one call to
setIsRecyclabe(false)
should always be matched with a later call to
setIsRecyclable(true)
).
这意味着 none 的 ViewHolder
对象将被回收,有效地使 RecyclerView
的使用变得毫无价值,并防止它在您尝试绑定新对象时重用视图反对你的 RecyclerView
.
所以,简而言之,删除那行代码。
我还注意到您的适配器代码还有其他一些小问题,这些问题将来可能会引起很多麻烦;所以我冒昧地强调了一些我会做出的改变。
为了我自己的理智,我将您的 Articles
class 称为 Article
。
把你的 Context
到处乱扔通常不是个好主意。传递给您的 ViewHolder
的 View
已经引用了 Context
,因此您可以改用它。
至于 insertArticle()
代码,Activity
无论如何都应该处理这个问题。因此,您可以通过将侦听器传递给您的 Adapter
(以及随后的每个 ViewHolder
)而不是 Context
,将 Article
传递回 Activity
。 =46=]
您还应该考虑使用 DiffUtil
class 而不是仅仅调用 notifyDataSetChanged()
;它更有效率。只需确保您的 Article
class 正在实施 equals()
和 hashCode()
否则它将不起作用。
我没有包括动画代码(可以很容易地添加回去)或保存的状态代码(主要是因为我不知道你想做什么)。
public class ArticleAdapter extends RecyclerView.Adapter<Article> {
private List<Article> mData;
private ArticleViewHolder.OnSelectedListener mOnSelectedListener;
private ArticleViewHolder.OnSaveListener mOnSaveListener;
public ArticleAdapter(ArticleViewHolder.OnSelectedListener onSelectedListener, ArticleViewHolder.OnSaveListener onSaveListener) {
mOnSelectedListener = onSelectedListener;
mOnSaveListener = onSaveListener;
mData = new ArrayList<>();
}
public void replaceData(final List<Article> data) {
final List<Article> oldData = new ArrayList<>(mData);
mData.clear();
if (data != null) {
mData.addAll(data);
}
DiffUtil.calculateDiff(new DiffUtil.Callback() {
@Override
public int getOldListSize() {
return oldData.size();
}
@Override
public int getNewListSize() {
return mData.size();
}
@Override
public int areItemsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
@Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
}).dispatchUpdatesTo(this);
}
@Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
return new SelectLocationViewHolder(view, mOnSelectedListener, mOnSaveListener);
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bind(mData.get(position));
}
@Override
public int getItemCount() {
return mData.size();
}
}
public class ArticleViewHolder extends RecyclerView.ViewHolder {
public interface OnSelectedListener {
void onSelected(Article article);
}
public interface OnSaveListener {
void onSave(Article article);
}
private View mView;
private Article mArticle;
private OnSelectedListener mOnSelectedListener;
private OnSaveListener mOnSaveListener;
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
public ArticleViewHolder(View itemView, final OnSelectedListener onSelectedListener, final OnSaveListener onSaveListener) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
mView = itemView;
mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
onSelectedListener.onSelected(mArticle);
}
});
mSaveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
onSaveListener.onSave(mArticle);
}
});
}
public void bind(Article article) {
mArticle = article;
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(TextUtils.isEmpty(article.getDescription())) {
mDescriptionTextView.setVisibility(View.GONE);
}
Glide.with(mView.getContext()).load(article.getImage()).into(mImageView);
}
}
编辑
实际问题是您的加载程序每次都使用相同的 ArrayList
,并不断向其中添加新结果。
public class NewsLoader extends AsyncTaskLoader<List<Article>> {
private final String[] mUrls;
private final OkHttpClient mClient;
public NewsLoader(Context context, OkHttpClient client, String... urls) {
super(context);
mClient = client;
mUrls = urls;
}
@Override
public List<Article> loadInBackground() {
List<Article> articles = new ArrayList<>();
for (String url : mUrls) {
Request request = new Request.Builder().url(url).build();
try {
Response response = mClient.newCall(request).execute();
if (response.isSuccessful()) {
parseData(response.body().string(), articles);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
}
return articles;
}
private void parseData(List<Article> articles, String data) throws JSONException {
JSONObject forecast = new JSONObject(data);
JSONArray a = forecast.getJSONArray("articles");
for (int i = 0; i < a.length(); i++) {
JSONObject o = a.getJSONObject(i);
Article article = new Article(
o.getString("title"),
o.getString("description"),
o.getString("url"),
o.getString("urlToImage"));
articles.add(article);
}
}
}
此外,您可能已经注意到,我对您的 Article
构造函数做了一个小改动。你应该考虑制作 Article
class immutable,因为这将防止你在处理多线程时出错。它应该看起来像这样:
public class Article {
private final String mTitle;
private final String mDescription;
private final String mUrl;
private final String mImageUrl;
public Article(String title, String description, String url, String imageUrl) {
mTitle = title;
mDescription = description;
mUrl = url;
mImageUrl = imageUrl;
}
public String title() {
return mTitle;
}
public String description() {
return mDescription;
}
public String url() {
return mUrl;
}
public String imageUrl() {
return mImageUrl;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Article other = (Article) o;
return mTitle != null && mTitle.equals(other.mTitle) &&
mDescription != null && mDescription.equals(other.mDescription) &&
mUrl != null && mUrl.equals(other.mUrl) &&
mImageUrl != null && mImageUrl.equals(other.mImageUrl);
}
@Override
public int hashCode() {
int result = mTitle != null ? mTitle.hashCode() : 0;
result = 31 * result + (mDescription != null ? mDescription.hashCode() : 0);
result = 31 * result + (mUrl != null ? mUrl.hashCode() : 0);
result = 31 * result + (mImageUrl != null ? mImageUrl.hashCode() : 0);
return result;
}
}
我有一个问题,当我滑动刷新数据时,第一次滑动没问题,但之后每次滑动都重新加载并一遍又一遍地添加相同的数据,到最后我有一个包含相同项目的列表以及...我正在使用装载机。 我之前尝试清除,但我不明白我的代码有什么问题,如果有人可以向我解释的话。谢谢你。
这是我的代码:
public abstract class NewsFragment extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<Articles>> {
protected ItemAdapter mArticleAdapter;
protected RecyclerView mRecyclerView;
protected NewsFragment.OnNewSelectedInterface mListener;
protected RecyclerView.LayoutManager mManager;
protected SwipeRefreshLayout mSwipeRefreshLayout;
protected LoaderManager mLoaderManager;
private boolean mStateSaved;
private static final int NEWS_LOAD_ID = 1;
public static final String KEY_LIST = "key_list";
public interface OnNewSelectedInterface {
void onListNewSelected(int index, ArrayList<Articles> articles);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.list_present_news, container, false);
mListener = (NewsFragment.OnNewSelectedInterface) getActivity();
mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipeContainer);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);
mManager = new LinearLayoutManager(getActivity());
mArticleAdapter = new ItemAdapter(getActivity(), new ArrayList<Articles>(), mListener);
mLoaderManager = getLoaderManager();
mStateSaved = mArticleAdapter.isStateSaved();
mRecyclerView.setAdapter(mArticleAdapter);
mRecyclerView.setLayoutManager(mManager);
getData();
refreshData();
if(!isNetworkAvailable())alertUserAboutError();
setDivider();
return view;
}
private void setDivider() {
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(mRecyclerView
.getContext(), DividerItemDecoration.VERTICAL);
mRecyclerView.addItemDecoration(dividerItemDecoration);
}
private void getData() {
getLoaderManager().initLoader(NEWS_LOAD_ID, null, this).forceLoad();
}
private void alertUserAboutError() {
AlertDialogFragment alertDialogFragment = new AlertDialogFragment();
alertDialogFragment.show(getActivity().getFragmentManager(), "error_dialog");
}
protected abstract String[] getUrl();
private boolean isNetworkAvailable() {
ConnectivityManager manager = (ConnectivityManager)
getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if (networkInfo != null && networkInfo.isConnected()) {
isAvailable = true;
}
return isAvailable;
}
private void refreshData() {
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
mArticleAdapter.clear();
mSwipeRefreshLayout.setRefreshing(false);
}
});
mSwipeRefreshLayout.setColorSchemeResources(
android.R.color.holo_orange_light,
android.R.color.holo_red_light);
}
@Override
public Loader<ArrayList<Articles>> onCreateLoader(int id, Bundle args) {
return new NewsLoader(getActivity(), getUrl());
}
@Override
public void onLoadFinished(Loader<ArrayList<Articles>> loader, ArrayList<Articles> data) {
if (data != null && !data.isEmpty()) {
mArticleAdapter.addAll(data);
}
}
@Override
public void onLoaderReset(Loader<ArrayList<Articles>> loader) {
mArticleAdapter.clear();
}
}
我的装载机 class:
public class NewsLoader extends AsyncTaskLoader<ArrayList<Articles>>{
private ArrayList<Articles> mArticlesArrayList;
private String[] mUrl;
public NewsLoader(Context context, String[] url) {
super(context);
mUrl = url;
}
@Override
public ArrayList<Articles> loadInBackground() {
OkHttpClient mClient = new OkHttpClient();
for (String aMUrl : mUrl) {
Request mRequest = new Request.Builder().url(aMUrl).build();
try {
Response response = mClient.newCall(mRequest).execute();
try {
if (response.isSuccessful()) {
String json = response.body().string();
getMultipleUrls(json);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return mArticlesArrayList;
}
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
private ArrayList<Articles> getArticleForecast(String jsonData) throws JSONException {
JSONObject forecast = new JSONObject(jsonData);
JSONArray articles = forecast.getJSONArray("articles");
ArrayList<Articles> listArticles = new ArrayList<>(articles.length());
for (int i = 0; i < articles.length(); i++) {
JSONObject jsonArticle = articles.getJSONObject(i);
Articles article = new Articles();
String urlImage = jsonArticle.getString("urlToImage");
article.setTitle(jsonArticle.getString("title"));
article.setDescription(jsonArticle.getString("description"));
article.setImageView(urlImage);
article.setArticleUrl(jsonArticle.getString("url"));
listArticles.add(i, article);
}
return listArticles;
}
}
我的适配器class:
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ArticleViewHolder> {
private static final String TAGO = ItemAdapter.class.getSimpleName();
private final NewsFragment.OnNewSelectedInterface mListener;
private ArrayList<Articles> mArticlesList;
private Context mContext;
private int lastPosition = -1;
private boolean mStateSaved = false;
public boolean isStateSaved() {
return mStateSaved;
}
public void setStateSaved(boolean stateSaved) {
mStateSaved = stateSaved;
}
public ItemAdapter(Context context, ArrayList<Articles> articles, NewsFragment.OnNewSelectedInterface listener){
mContext = context;
mArticlesList = articles;
mListener = listener;
}
@Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
ArticleViewHolder articleViewHolder = new ArticleViewHolder(view);
articleViewHolder.setIsRecyclable(false);
return articleViewHolder;
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(holder.getAdapterPosition()));
setAnimation(holder.itemView, holder.getAdapterPosition());
}
private void setAnimation(View viewToAnimate, int position) {
if (position > lastPosition) {
Animation animation = AnimationUtils.loadAnimation(viewToAnimate.getContext(), android.R.anim.slide_in_left);
viewToAnimate.startAnimation(animation);
lastPosition = position;
}
}
@Override
public int getItemCount() {
return mArticlesList.size();
}
public void clear() {
mArticlesList.clear();
notifyDataSetChanged();
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
protected class ArticleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
private ArticleViewHolder(View itemView) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
itemView.setOnClickListener(this);
}
private void bindArticle(final Articles article) {
Glide.with(mContext).load(article.getImageView()).into(mImageView);
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(mDescriptionTextView.getText().equals("")){
mDescriptionTextView.setVisibility(View.GONE);
}
mSaveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
insertArticle(article);
article.setStateSaved(true);
}
});
Log.v(TAGO, "Item id : " + getItemId()
+ "Item count : " + getItemCount()
+ "Item position : " + getAdapterPosition()
+ String.valueOf(article.isStateSaved()));
}
private void insertArticle(Articles articles) {
String title = articles.getTitle();
String description = articles.getDescription();
String url = articles.getArticleUrl();
ContentValues contentValues = new ContentValues();
contentValues.put(ArticleContract.ArticleEntry.COLUMN_TITLE_ARTICLE, title);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_DESCRIPTION_ARTICLE, description);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_URL_ARTICLE, url);
Uri uri = mContext.getContentResolver().insert(ArticleContract.ArticleEntry.CONTENT_URI, contentValues);
if(uri == null) {
Log.v(TAGO, "Error");
} else Toast.makeText(mContext, "Article Saved", Toast.LENGTH_SHORT).show();
}
@Override
public void onClick(View view) {
mListener.onListNewSelected(getLayoutPosition(), mArticlesList);
}
}
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(position));
setAnimation(holder.itemView, position);
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.clear();
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
如果这不起作用,那么我认为您的 api 给您提供了冗余数据。
为什么使用 articleViewHolder.setIsRecyclable(false);
另一个可能导致问题的地方是
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
您正在从一个循环中调用它,将数据添加到您的数组列表中。您的 ArrayList
您使用的 ViewHolder#setIsRecyclable
不正确;此方法旨在用于防止 ViewHolder
在对其进行更改时 仅 被回收。根据文档:
Calls to
setIsRecyclable()
should always be paired (one call tosetIsRecyclabe(false)
should always be matched with a later call tosetIsRecyclable(true)
).
这意味着 none 的 ViewHolder
对象将被回收,有效地使 RecyclerView
的使用变得毫无价值,并防止它在您尝试绑定新对象时重用视图反对你的 RecyclerView
.
所以,简而言之,删除那行代码。
我还注意到您的适配器代码还有其他一些小问题,这些问题将来可能会引起很多麻烦;所以我冒昧地强调了一些我会做出的改变。
为了我自己的理智,我将您的 Articles
class 称为 Article
。
把你的 Context
到处乱扔通常不是个好主意。传递给您的 ViewHolder
的 View
已经引用了 Context
,因此您可以改用它。
至于 insertArticle()
代码,Activity
无论如何都应该处理这个问题。因此,您可以通过将侦听器传递给您的 Adapter
(以及随后的每个 ViewHolder
)而不是 Context
,将 Article
传递回 Activity
。 =46=]
您还应该考虑使用 DiffUtil
class 而不是仅仅调用 notifyDataSetChanged()
;它更有效率。只需确保您的 Article
class 正在实施 equals()
和 hashCode()
否则它将不起作用。
我没有包括动画代码(可以很容易地添加回去)或保存的状态代码(主要是因为我不知道你想做什么)。
public class ArticleAdapter extends RecyclerView.Adapter<Article> {
private List<Article> mData;
private ArticleViewHolder.OnSelectedListener mOnSelectedListener;
private ArticleViewHolder.OnSaveListener mOnSaveListener;
public ArticleAdapter(ArticleViewHolder.OnSelectedListener onSelectedListener, ArticleViewHolder.OnSaveListener onSaveListener) {
mOnSelectedListener = onSelectedListener;
mOnSaveListener = onSaveListener;
mData = new ArrayList<>();
}
public void replaceData(final List<Article> data) {
final List<Article> oldData = new ArrayList<>(mData);
mData.clear();
if (data != null) {
mData.addAll(data);
}
DiffUtil.calculateDiff(new DiffUtil.Callback() {
@Override
public int getOldListSize() {
return oldData.size();
}
@Override
public int getNewListSize() {
return mData.size();
}
@Override
public int areItemsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
@Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
}).dispatchUpdatesTo(this);
}
@Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
return new SelectLocationViewHolder(view, mOnSelectedListener, mOnSaveListener);
}
@Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bind(mData.get(position));
}
@Override
public int getItemCount() {
return mData.size();
}
}
public class ArticleViewHolder extends RecyclerView.ViewHolder {
public interface OnSelectedListener {
void onSelected(Article article);
}
public interface OnSaveListener {
void onSave(Article article);
}
private View mView;
private Article mArticle;
private OnSelectedListener mOnSelectedListener;
private OnSaveListener mOnSaveListener;
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
public ArticleViewHolder(View itemView, final OnSelectedListener onSelectedListener, final OnSaveListener onSaveListener) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
mView = itemView;
mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
onSelectedListener.onSelected(mArticle);
}
});
mSaveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
onSaveListener.onSave(mArticle);
}
});
}
public void bind(Article article) {
mArticle = article;
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(TextUtils.isEmpty(article.getDescription())) {
mDescriptionTextView.setVisibility(View.GONE);
}
Glide.with(mView.getContext()).load(article.getImage()).into(mImageView);
}
}
编辑
实际问题是您的加载程序每次都使用相同的 ArrayList
,并不断向其中添加新结果。
public class NewsLoader extends AsyncTaskLoader<List<Article>> {
private final String[] mUrls;
private final OkHttpClient mClient;
public NewsLoader(Context context, OkHttpClient client, String... urls) {
super(context);
mClient = client;
mUrls = urls;
}
@Override
public List<Article> loadInBackground() {
List<Article> articles = new ArrayList<>();
for (String url : mUrls) {
Request request = new Request.Builder().url(url).build();
try {
Response response = mClient.newCall(request).execute();
if (response.isSuccessful()) {
parseData(response.body().string(), articles);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
}
return articles;
}
private void parseData(List<Article> articles, String data) throws JSONException {
JSONObject forecast = new JSONObject(data);
JSONArray a = forecast.getJSONArray("articles");
for (int i = 0; i < a.length(); i++) {
JSONObject o = a.getJSONObject(i);
Article article = new Article(
o.getString("title"),
o.getString("description"),
o.getString("url"),
o.getString("urlToImage"));
articles.add(article);
}
}
}
此外,您可能已经注意到,我对您的 Article
构造函数做了一个小改动。你应该考虑制作 Article
class immutable,因为这将防止你在处理多线程时出错。它应该看起来像这样:
public class Article {
private final String mTitle;
private final String mDescription;
private final String mUrl;
private final String mImageUrl;
public Article(String title, String description, String url, String imageUrl) {
mTitle = title;
mDescription = description;
mUrl = url;
mImageUrl = imageUrl;
}
public String title() {
return mTitle;
}
public String description() {
return mDescription;
}
public String url() {
return mUrl;
}
public String imageUrl() {
return mImageUrl;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Article other = (Article) o;
return mTitle != null && mTitle.equals(other.mTitle) &&
mDescription != null && mDescription.equals(other.mDescription) &&
mUrl != null && mUrl.equals(other.mUrl) &&
mImageUrl != null && mImageUrl.equals(other.mImageUrl);
}
@Override
public int hashCode() {
int result = mTitle != null ? mTitle.hashCode() : 0;
result = 31 * result + (mDescription != null ? mDescription.hashCode() : 0);
result = 31 * result + (mUrl != null ? mUrl.hashCode() : 0);
result = 31 * result + (mImageUrl != null ? mImageUrl.hashCode() : 0);
return result;
}
}