【发布时间】：2019-01-21 11:27:17
【问题描述】：
尝试应用 onLoadmore 功能，在我更新每个请求的适配器后 Recyclerview 带到第一个元素，我想从最后添加的列表中继续查看
MainActivity 代码：
public class Inbox extends Fragment {
private RecyclerView mRecycler;
private InboxAdapter mAdapter;
SwipeRefreshLayout swipeContainer;
TextView txtnomail;
static String strtoken;
static int inboxcount;
ImageView Img;
List<MailDataModel> data = new ArrayList<>();
private Context context = null;
int page;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootview=inflater.inflate(R.layout.fragment_inbox, container, false);
Img=rootview.findViewById(R.id.gifloader);
mRecycler = (RecyclerView)rootview.findViewById(R.id.inbox_recycler);
txtnomail = (TextView) rootview.findViewById(R.id.nomail_inbox);
swipeContainer=(SwipeRefreshLayout)rootview.findViewById(R.id.swipeContainer_inbox);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
SharedPreferences.Editor editor = prefs.edit();
inboxcount = prefs.getInt("inboxcount", 0);
editor.apply();
MainActivity activity = (MainActivity) getActivity();
assert activity != null;
strtoken = activity.getMyData();
RetrieveInboxMails retrieveInboxMails=new RetrieveInboxMails();
retrieveInboxMails.execute(String.valueOf(page));
context=getActivity();
swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
RetrieveInboxMails retrieveInbox=new RetrieveInboxMails();
retrieveInbox.execute(String.valueOf(page));
}
});
// Configure the refreshing colors
swipeContainer.setColorSchemeResources(
android.R.color.holo_blue_light,
android.R.color.holo_blue_light,
android.R.color.holo_blue_light,
android.R.color.holo_blue_dark);
mAdapter = new InboxAdapter(mRecycler, context, data);
mRecycler.setAdapter(mAdapter);
mAdapter.notifyItemInserted(data.size());
return rootview;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//you can set the title for your toolbar here for different fragments different titles
getActivity().setTitle("Inbox");
}
public class RetrieveInboxMails extends AsyncTask<String, String, String> {
List<MailDataModel> tempdata = new ArrayList<>();
final MailDataModel health = new MailDataModel();
@Override
protected void onPreExecute() {
// Img.setVisibility(View.VISIBLE);
// txtnomail.setVisibility(View.GONE);
}
@Override
protected String doInBackground(String... strings) {
try {
String pages=strings[0];
// Creating & connection Connection with url and required Header.
URL url = new URL("http://api-
telemed.3cubehealth.com/api/fetchLocalEmails?
category=inbox&limit="+10+"&page="+pages);
// URL url = new URL("http://api-
telemed.3cubehealth.com/api/fetchLocalEmails?
category=inbox&limit=10&page=0");
HttpURLConnection urlConnection = (HttpURLConnection)
url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setRequestProperty("Content-Type",
"application/json");
urlConnection.setRequestProperty("Authorization", "Bearer " +
strtoken);
urlConnection.setDoInput(true);
//POST or GET
urlConnection.connect();
int statusCode = urlConnection.getResponseCode();
// Connection success. Proceed to fetch the response.
if (statusCode == 200) {
InputStream it = new
BufferedInputStream(urlConnection.getInputStream());
InputStreamReader read = new InputStreamReader(it);
BufferedReader buff = new BufferedReader(read);
StringBuilder dta = new StringBuilder();
String chunks;
while ((chunks = buff.readLine()) != null) {
dta.append(chunks);
}
chunks = dta.toString();
return chunks;
}
} catch (ProtocolException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return strtoken;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
swipeContainer.setRefreshing(false);
Img.setVisibility(View.GONE);
try {
JSONArray jsonArray = new JSONArray(result);
// Extract data from json and store into ArrayList as class
objects
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject json_data = jsonArray.getJSONObject(i);
health.setVessalName(json_data.getString("from_name"));
health.setEmailId(json_data.getString("from_email"));
health.setId(json_data.getInt("id"));
health.setSubject(json_data.getString("subject"));
health.setTransId(json_data.getInt("trans_id"));
String date = json_data.getString("message_date");
String message = json_data.getString("message_html");
health.setStatus(json_data.getString("email_status"));
if (context != null) {
SharedPreferences prefs_file =
PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor_file = prefs_file.edit();
editor_file.putString("result", result);
editor_file.apply();
}
health.setMessage(message);
DateFormat inputFormatter1 = new SimpleDateFormat("yyyy-MM-
dd");
Date date1 = inputFormatter1.parse(date);
DateFormat outputFormatter1 = new SimpleDateFormat("d MMM");
String output1 = outputFormatter1.format(date1);
health.setDate(output1);
data.add(health);
if (context != null) {
mRecycler.setLayoutManager(new
LinearLayoutManager(context));
}
}
mAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
@Override
public void onLoadMore() {
if (data.size() <=inboxcount) {
data.add(null);
mAdapter.notifyItemInserted(data.size());
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
data.remove(data.size() -1);
mAdapter.notifyItemRemoved(data.size());
page++;
new
RetrieveInboxMails().execute(String.valueOf(page));
mAdapter.notifyDataSetChanged();
mAdapter.setLoaded();
}
}, 2000);
} else {
Toast.makeText(context, "Loading data completed",
Toast.LENGTH_SHORT).show();
}
}
});
}
catch(JSONException e){
e.printStackTrace();
} catch(ParseException e){
e.printStackTrace();
}
}
}
@Override
public void onPrepareOptionsMenu(Menu menu) {
MenuItem mSearchMenuItem = menu.findItem(R.id.option_menu_search);
SearchView searchView = (SearchView) mSearchMenuItem.getActionView();
searchView.setImeOptions(EditorInfo.IME_ACTION_DONE);
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
mAdapter.getFilter().filter(newText);
return false;
}
});
}
}
适配器代码：
public class InboxAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements Filterable {
Context mcontext;
LayoutInflater inflater;
List<MailDataModel> mailDataModelList;
List<MailDataModel> exampleListFull;
final int VIEW_TYPE_ITEM = 0;
final int VIEW_TYPE_LOADING = 1;
boolean isLoading;
private int visibleThreshold = 8;
private int lastVisibleItem, totalItemCount;
OnLoadMoreListener onLoadMoreListener;
public InboxAdapter(RecyclerView recyclerView, Context context,List<MailDataModel> mailDataModelList) {
this.mcontext = context;
// this.inflater = LayoutInflater.from(context);
this.inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.mailDataModelList = mailDataModelList;
exampleListFull=new ArrayList<>(mailDataModelList);
notifyItemRangeChanged(0, mailDataModelList.size()-1);
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findFirstVisibleItemPosition();
// lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading&&totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (onLoadMoreListener != null) {
onLoadMoreListener.onLoadMore();
}
isLoading = true;
}
}
});
}
@Override
public int getItemViewType(int position) {
return mailDataModelList.get(position) == null ? VIEW_TYPE_LOADING : VIEW_TYPE_ITEM;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
View view = LayoutInflater.from(mcontext).inflate(R.layout.layout_unread, parent, false);
return new InboxMailsHolder(view);
} else if (viewType == VIEW_TYPE_LOADING) {
View view = LayoutInflater.from(mcontext).inflate(R.layout.item_loading, parent, false);
return new LoadingViewHolder(view);
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof InboxMailsHolder) {
final MailDataModel data = mailDataModelList.get(position);
final InboxMailsHolder inboxdMailsHolder = (InboxMailsHolder) holder;
inboxdMailsHolder.date.setText(data.getDate());
inboxdMailsHolder.subject.setText(data.getSubject());
switch (data.getStatus()) {
case "Read":
inboxdMailsHolder.cardView.setBackgroundColor(Color.WHITE);
break;
case "Sent":
inboxdMailsHolder.cardView.setBackgroundColor(Color.WHITE);
break;
// 案例“未读”： // inboxdMailsHolder.cardView.setBackgroundColor(Color.parseColor("#EBEBEB")); 默认： inboxdMailsHolder.cardView.setBackgroundColor(Color.parseColor("#EBEBEB")); 休息; } if (data.getVessalName().equals("null")) { inboxdMailsHolder.emailid.setText(data.getEmailId());
} else {
inboxdMailsHolder.emailid.setText(data.getVessalName());
}
inboxdMailsHolder.cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
new UnReadAdapter.MailStatusAsync(mcontext).execute(String.valueOf(data.getId()));
inboxdMailsHolder.subject.setTypeface(null, Typeface.NORMAL);
inboxdMailsHolder.cardView.setBackgroundColor(Color.WHITE);
Intent email_intent = new Intent(view.getContext(), MailDetails.class);
email_intent.putExtra("Date", data.getDate());
email_intent.putExtra("TransId", data.getTransId());
email_intent.putExtra("Id", data.getId());
email_intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
mcontext.startActivity(email_intent);
}
});
}
else if (holder instanceof LoadingViewHolder) {
LoadingViewHolder loadingViewHolder = (LoadingViewHolder) holder;
loadingViewHolder.progressBar.setIndeterminate(false);
}
}
@Override
public int getItemCount() {
return mailDataModelList == null ? 0 : mailDataModelList.size();
}
public void setLoaded() {
isLoading = false;
}
private class LoadingViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;
public LoadingViewHolder(View view) {
super(view);
progressBar = (ProgressBar) view.findViewById(R.id.progressBar1);
}
}
public class InboxMailsHolder extends RecyclerView.ViewHolder{
TextView emailid,subject,date;
CardView cardView;
public InboxMailsHolder(@NonNull View itemView) {
super(itemView);
emailid=itemView.findViewById(R.id.email_id);
subject=itemView.findViewById(R.id.subject);
date=itemView.findViewById(R.id.date);
cardView=itemView.findViewById(R.id.mailcard);
}
}
@Override
public Filter getFilter() {
return exampleFilter;
}
private Filter exampleFilter = new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
List<MailDataModel> filteredList = new ArrayList<>();
if (constraint == null || constraint.length() == 0) {
filteredList.addAll(exampleListFull);
} else {
String filterPattern = constraint.toString().toLowerCase().trim();
for (MailDataModel item : exampleListFull) {
if (item.getEmailId().toLowerCase().contains(filterPattern)||item.getSubject().toLowerCase().contains(filterPattern)||item.getMessage().toLowerCase().contains(filterPattern)|| item.getStatus().toLowerCase().contains(filterPattern)) {
filteredList.add(item);
}
}
}
FilterResults results = new FilterResults();
results.values = filteredList;
return results;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
mailDataModelList.clear();
mailDataModelList.addAll((List) results.values);
notifyDataSetChanged();
}
};
public void setOnLoadMoreListener(OnLoadMoreListener mOnLoadMoreListener) {
this.onLoadMoreListener = mOnLoadMoreListener;
}
}
【问题讨论】：
-
请同时添加代码。
-
请立即查看
-
使用google的paging支持库
-
但这现在几乎完成了，数据是逐页加载的，唯一的问题是适配器在新请求后附加新数据后，回收器视图刷新页面并显示第一个数据
-
当您将项目添加到您的列表时调用
notifyDataSetChanged()方法而不是此notifyItemInserted(data.size());更新您的列表，然后调用此方法notifyDataSetChanged()。