Halo, I have LoadMore RecyclerView in my app. it's work, but when i'm load more item, the recyclerview always keep showing the top of the list. I mean, it should be shown the last item loaded.
Anyone, would you like to help me? thanks.
my screenshoot :
1 - 5 is the first list loaded:
6 - 10 shown after scrolling the recyclerView, but after 6 - 10
loaded, recyclerView always keep showing the top of the list (1-5)
:
this is my code :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_job_company);
//intent untuk nerima value namaAdver dan handling jika tdk ada list
TextView namaCompany = (TextView) findViewById(R.id.tv_companyname);
TextView emptyList = (TextView) findViewById(R.id.emptylist);
loading = (ProgressBar) findViewById(R.id.loading);
loading.getIndeterminateDrawable().setColorFilter(getResources().getColor(R.color.colorPrimary), PorterDuff.Mode.MULTIPLY);
Intent intentGet = getIntent();
companyName = intentGet.getStringExtra("namaCompany");
idComp = intentGet.getStringExtra("idCompany");
try {
compID = Integer.parseInt(idComp);
} catch (NumberFormatException nfe) {
}
namaCompany.setText(companyName);
setTitle(intentGet.getStringExtra("namaCompany"));
PaginationJobCompany(compID, pageNum);
recyclerView = (RecyclerView) findViewById(R.id.rv_job_company2);
recyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.addItemDecoration(new DividerItemDecoration(getApplicationContext(), null)); //untuk divider
}
private void PaginationJobCompany(final int compID, final int pageNumber) {
try {
loading.getIndeterminateDrawable().setColorFilter(getResources().getColor(R.color.colorPrimary), PorterDuff.Mode.MULTIPLY);
loading.setVisibility(View.GONE);
//authorization JWT pref_token berdasarkan string yg disimpan di preferenceManager pada class login.
Authorization = (PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).getString(
getResources().getString(R.string.pref_token), ""));
//production
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(getResources().getString(R.string.base_url))
.addConverterFactory(GsonConverterFactory.create())
.build();
//assign variabel request ke class interface TabAdverRequest
final APIInterfaces request = retrofit.create(APIInterfaces.class);
Call<ReportJobModel> call = request.getReportPagination(compID, pageNum, length, Authorization); //ngirim ke API
call.enqueue(new Callback<ReportJobModel>() {
#Override
public void onResponse(Call<ReportJobModel> call, Response<ReportJobModel> response) {
loading.getIndeterminateDrawable().setColorFilter(getResources().getColor(R.color.colorPrimary), PorterDuff.Mode.MULTIPLY);
loading.setVisibility(View.GONE);
if (response.isSuccessful()) {
companyResult = response.body().getResult();
if (!companyResult.isEmpty()) {
company.addAll(companyResult);
for (int i = 0; i < companyResult.size(); i++) {
if (company.get(i).getCompanyID() == compID) {
jobItemResult = response.body().getResult().get(i).getJobs();
jobItem.addAll(jobItemResult);
}
}
}
else {
for (int j = 0; j < companyResult.size(); j++) {
if (company.get(j).getCompanyID() == compID) {
lastId = jobItem.size()-1;
}
}
}
adapter = new JobCompanyAdapter(jobItem, recyclerView);
recyclerView.setAdapter(adapter);
adapter.setOnLoadMoreListener(new OnLoadMoreListener() {
#Override
public void onLoadMore() {
//add null , so the adapter will check view_type and show progress bar at bottom
jobItem.add(null);
adapter.notifyItemInserted(jobItem.size() - 1);
loading.getIndeterminateDrawable().setColorFilter(getResources().getColor(R.color.colorPrimary), PorterDuff.Mode.MULTIPLY);
loading.setVisibility(View.GONE);
handler.postDelayed(new Runnable() {
#Override
public void run() {
jobItem.remove(jobItem.size() - 1);
adapter.notifyItemRemoved(jobItem.size());
loading.setVisibility(View.GONE);
pageNum++;
loading.setVisibility(View.GONE);
PaginationJobCompany(compID, pageNum);
adapter.notifyDataSetChanged();
}
}, 2000);
}
});
} else if (response.errorBody() != null) {
loading.setVisibility(View.GONE);
Toast.makeText(getApplicationContext(), "Gagal Memuat. Periksa Koneksi Anda!", Toast.LENGTH_LONG).show();
} else if (response.code() == 400) {
loading.setVisibility(View.GONE);
Toast.makeText(getApplicationContext(), "Gagal Memuat. Periksa Koneksi Anda!", Toast.LENGTH_LONG).show();
} else {
loading.setVisibility(View.GONE);
Toast.makeText(getApplicationContext(), "Gagal Memuat. Periksa Koneksi Anda! 1", Toast.LENGTH_LONG).show();
}
}
#Override
public void onFailure(Call<ReportJobModel> call, Throwable t) {
Toast.makeText(getApplicationContext(), "Gagal Memuat. Periksa Koneksi Anda! 1", Toast.LENGTH_LONG).show();
}
});
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "Gagal Memuat. Periksa Koneksi Anda! 1", Toast.LENGTH_LONG).show();
}
}
Okay I'll assume that you already have an implementation of the EndlessScrollListener for the RecyclerView if not, I urge you check out this: https://gist.github.com/nesquena/d09dc68ff07e845cc622. Further to make your code more readable and adaptable, I would recommend that you use more encapsulation.
For example: Have a NetworkHandler that does the callbacks for you to the UI. Where you switch the UI behaviour accordingly. To do that you need a OnDataCallback interface.
// OnDataCallback.java
interface OnDataCallback<T> {
void onData(T data);
void onError(Throwable error);
}
// NetworkHandler.java
public class NetworkHandler<T> {
#Nullable
protected OnDataCallback<T> dataCallback;
protected int pageIndex = 0;
public void setDataCallback(OnDataCallback<T> dataCallback) {
this.dataCallback = dataCallback;
}
public void removeDataCallback() {
dataCallback = null;
}
public void setPageIndex(int pageIndex) {
this.pageIndex = pageIndex;
}
public void updatePageNumber() {
pageIndex++;
}
}
Create a RetrofitUtils class as a Singleton that could be used to creating the services.
public static class RetrofitUtils {
private static RetrofitUtils utils;
public static RetrofitUtils getInstance() {
if (utils == null) {
utils = new RetrofitUtils();
}
return utils;
}
private Retrofit retrofit;
public Retrofit getRetrofitInstance(){
if (retrofit == null) {
retrofit = new Retrofit.Builder()
.baseUrl("http://mybaseurl.api/v1/")
.addConverterFactory(GsonConverterFactory.create())
.build();
}
return retrofit;
}
public JobService constructJobService(Class<JobService> uClass) {
return getRetrofitInstance().create(uClass);
}
public LoginService construcstLoginService(Class<LoginService> uClass) {
return getRetrofitInstance().create(uClass);
}
}
Then inherit the NetworkHandler and override the methods according to your specifications for example have a JobNetworkHandler that does the request and paging for you. Create custom Throwable classes to handle error more efficiently like in the example it is ErrorBodyThrowable. All that is left is you have to implement the callback and set UI in fragment or activity.
public class JobReportHandler extends NetworkHandler<ReportJobModel> {
int compID;
int length;
Authorization auth = AuthUtils.getAuth();
#Override
public void updatePageNumber() {
super.updatePageNumber();
fetchJobsModel(compID, length);
}
public void fetchJobsModel(int compID, int length) {
this.compID = compID;
this.length = length;
JobService request = RetrofitUtils.getInstance().constructJobService(JobService.class);
Call<ReportJobModel> call = request.getReportPagination(compID, pageIndex, length, auth); //ngirim ke API
call.enqueue(new Callback<JobModel>() {
#Override
public void onResponse(Call<JobModel> call, Response<JobModel> response) {
// manipulate data and pass the UI model
// that needs to be handled by the view
ReportJobModel reportJobModel = response.convertToReport();
if (dataCallback == null) return;
if (response.isSuccessful()) {
dataCallback.onData(reportJobModel);
} else if (response.errorBody() != null) {
dataCallback.onError(new ErrorBodyThrowable());
} else if (response.code() == 400) {
dataCallback.onError(new ApiError());
} else {
// do something else
}
}
#Override
public void onFailure(Call<ReportJobModel> call, Throwable t) {
if (dataCallback != null) {
dataCallback.onError(t);
}
}
});
}
public class ErrorBodyThrowable extends Throwable {
ErrorBodyThrowable() {
super("Gagal Memuat. Periksa Koneksi Anda!");
}
}
}
Note that updating the pageIndex automatically triggers the network call so you avoid writing redundant calls.
Finally in your Fragment or Activity have something like this:
// TestFragment.java
public final class TestFragment extends Fragment implements OnDataCallback<ReportJobModel>, CustomRecyclerOnScrollListener {
#Bind(R.id.myRecyclerView)
RecyclerView myRecyclerView;
private JobsAdapter adapter;
private final JobReportHandler jobHandler = new JobReportHandler();
private final Handler mainThreadHandler = new Handler(Looper.getMainLooper());
private MyCustomEndlessScrollListener endlessScroll;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.my_list_fragment, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
endlessScroll = = new MyCustomEndlessScrollListener(this);
setUi();
initializeNetwork();
}
private void initializeNetwork() {
// after setting the UI Parameters
jobHandler.setDataCallback(this);
jobHandler.fetchJobsModel(compID, length);
}
#Override
public void onData(ReportJobModel dataModel) {
// just a safety mechanism to handle threading
// use the main thread dispatcher
mainThreadHandler.post(new Runnable() {
#Override
public void run() {
final ArrayList<JobItem> data = dataModel.getJobItems();
UiUtils.makeGone(loadingProgress);
if (myRecyclerView.getAdapter() == null || jobAdapter == null) {
jobAdapter = JobsAdapter(data);
myRecyclerView.setAdapter(jobAdapter);
myRecyclerView.setOnScrollChangeListener(endlessScroll);
} else {
jobAdapter.getItems().addAll(data);
jobAdapter.notifyItemRangeInserted(jobAdapter.getItems().size() -1, data.size());
}
}
});
}
#Override
public void onScrolledToBottom() {
jobHandler.updatePageNumber();
}
#Override
public void onError(final Throwable error) {
// just a safety mechanism to handle threading
// use the main thread dispatcher
mainThreadHandler.post(new Runnable() {
#Override
public void run() {
if (error.getMessage() != null && !error.getMessage().isEmpty()) {
Toast.makeText(getContext(), error.getMessage(), Toast.LENGTH_LONG).show();
}
}
});
}
#Override
public void onDestroy() {
jobHandler.removeDataCallback();
super.onDestroy();
}
}
As you see the onScrolledToBottom() would be triggered through the CustomRecyclerScrollListener and this would then trigger the updatePageNumber() that would then call the fetchJobModel() and eventually you'll get a callback on your fragment.
Related
I'm trying to catch onMeetingStatusChanged event. But for my case, the onMeetingStatusChanged is sometimes invoked, not all the time. Below is my implemented code:
#Override
protected void onCreate(Bundle savedInstanceState) {
registerListener();
InitAuthSDKHelper.getInstance().initSDK(this, new InitAuthSDKCallback() {
#Override
public void onZoomSDKInitializeResult(int i, int i1) {
}
#Override
public void onZoomAuthIdentityExpired() {
}
});
}
private void registerListener() {
ZoomSDK zoomSDK = ZoomSDK.getInstance();
MeetingService meetingService = zoomSDK.getMeetingService();
if (meetingService != null) {
meetingService.addListener(this);
}
}
#Override
public void onMeetingStatusChanged(MeetingStatus meetingStatus,
int errorCode,
int internalErrorCode) {
LogD.d(TAG, String.valueOf(meetingStatus));
if (meetingStatus == MeetingStatus.MEETING_STATUS_IDLE) {
layout_zoom_loading.setVisibility(View.VISIBLE);
} else {
layout_zoom_loading.setVisibility(View.GONE);
}
if(meetingStatus == MeetingStatus.MEETING_STATUS_FAILED
&& errorCode == MeetingError.MEETING_ERROR_CLIENT_INCOMPATIBLE) {
Toast.makeText(this, "Version of ZoomSDK is too low!", Toast.LENGTH_LONG).show();
}
}
public void joinMeeting(String meetingNo, String meetingPassword) {
ZoomSDK zoomSDK = ZoomSDK.getInstance();
if (!zoomSDK.isInitialized()) {
Toast.makeText(this, getString(R.string.msg_zoom_init_fail), Toast.LENGTH_LONG).show();
return;
}
JoinMeetingHelper.getInstance().joinMeetingWithNumber(this, meetingNo, meetingPassword);
}
I see the cause of this problem. We need to separate the initSDK method to BaseActivity class. So when user forward into the next Activity which runs Zoom meeting, onMeetingStatusChanged always be invoked.
this is recyclerview where I am selecting the option and saving in activity but I want to select
only one option but it is selecting multiple this is the problem, and how to apply mainIndex I am handling in activity and then notify adapter.
#Override
public void onBindViewHolder(#NonNull final ExamQuestionViewHolder holder, int i) {
final ExamQuestionsOptionsItem item = itemList.get(i);
if (!TextUtils.isEmpty(item.getOption()) && item.getOption() != null){
holder.tvOption.setText(item.getOption());
}else {
holder.tvOption.setText("");
}
holder.rlMain.setSelected(item.isSelected());
holder.rlMain.setBackground(ContextCompat.getDrawable(context,
item.isSelected() ? R.drawable.preference_bg_selected : R.drawable.rect_box_white));
holder.rlMain.setAlpha(0.6f);
holder.tvOption.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
holder.rlMain.performClick();
}
});
holder.tvOption.setTextColor(ContextCompat.getColor(context,
item.isSelected() ? R.color.colorPrimary : R.color.font_color));
selecting options
holder.rlMain.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!isClickable)return;
holder.rlMain.setAlpha(0.6f);
item.setSelected(!item.isSelected());
holder.tvOption.setTextColor(ContextCompat.getColor(context,
item.isSelected() ? R.color.colorPrimary : R.color.font_color));
holder.rlMain.setBackground(ContextCompat.getDrawable(context,
item.isSelected() ? R.drawable.preference_bg_selected :
R.drawable.rect_box_white));
if (item.isSelected()){
selectedOptionList.add(item.getOptionId());
}else {
if (selectedOptionList != null)
selectedOptionList.remove(item.getOptionId());
}
if (selectedOptionList != null)
selectedOptionListner.selectedOptionList(selectedOptionList);
}
});
}
activity calling questions, answer options are appearing in recyclerview and question is in activity textview
protected void fetchQuestions() {
viewsDisable();
Call<ExamQuestionResponse> call =
ApiClient.getInstance().getMainApi().getExamQuestions(Util.getHeaderMap(token), examId);
call.enqueue(new Callback<ExamQuestionResponse>() {
#Override
public void onResponse(Call<ExamQuestionResponse> call, Response<ExamQuestionResponse>
response) {
viewsEnable();
if (response.body() != null) {
ExamQuestionResponse mResponse = response.body();
if (mResponse.isStatus()) {
questionList = mResponse.getData();
if (questionList != null && questionList.size() > 0) {
binding.tvQuestion.setText(questionList.get(mainIndex).getQuestion());
adapter = new ExamQuestionAdapter(ExamQuestionsActivity.this, optionList,
new ExamQuestionAdapter.RecyclerViewClickListener() {
#Override
public void recyclerViewListClicked(View v, int position) {
//adapter.notifyDataSetChanged();
}
}, new ExamQuestionAdapter.SelectedOptionList() {
#Override
public void selectedOptionList(ArrayList<String> list) {
selectedOptionList = list;
}
});
binding.recyclerview.setAdapter(adapter);
} else {
dataNotFound();
}
} else {
dataNotFound();
}
} else {
dataNotFound();
}
}
#Override
public void onFailure(Call<ExamQuestionResponse> call, Throwable t) {
viewsEnable();
}
});
}
// next button in activity, question is updating because i have mainIndex but option are in
// recyclerview they are not updating
binding.tvNext.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mainIndex++;
binding.tvQuestion.setText("");
binding.tvQuestion.setText(questionList.get(mainIndex).getQuestion());
adapter.notifyDataSetChanged();
}
});
I have solved the question I was not using proper indexes to move the index on button click.
I have used index++ or index-- on next and previous button click.
protected void showNextQuestion() {
boolean isAnyItemSelect = false;
List<ExamQuestionsOptionsItem> optionsItems =
examQuestionDataItemList.get(currentIndex).getOptions();
prefConfig.saveOptionsItem(optionsItems);
for (int i = 0; i < optionsItems.size(); i++) {
if (optionsItems.get(i).isSelected()) {
isAnyItemSelect = true;
break;
}
}
if (!isAnyItemSelect) {
Toast.makeText(this, "Please select any answer before proceeding",
Toast.LENGTH_SHORT).show();
return;
}
if (currentIndex == questionListSize - 1) {
showFinishAlert(this.getString(R.string.exam_going_to_finish));
} else {
currentIndex++;
prefConfig.writeRecoverIndex(currentIndex);
if(isReview && !examQuestionDataItemList.get(currentIndex).isReview() )
{
showNextQuestion();
return;
}
setQuestions();
}
}
I am trying to make a volley request to api's url. The problem is that data is fetched appropriately, but every time data set updates, the whole recycler view refreshes again and begins from the start; in the docs it is mentioned that use notifyDataSetChanged() as the last resort. How can it be avoided and what are the best practices for such tasks? Any design pattern that should be followed?
Here is the Fragment Code :-
public class PageFragment extends Fragment implements SortDialogCallback {
private static final String TAG = PageFragment.class.getSimpleName();
/**
* Unsplash API, By Default=10
*/
private static final String per_page = "10";
public static String order_By;
/**
* Unsplash API call parameter, By Default=latest
* Change it in Pager Fragment, based on Tab tapped
*/
RecyclerView recyclerView;
ImageAdapter imageAdapter;
GridLayoutManager layoutManager;
EndlessRecyclerViewScrollListener scrollListener;
FloatingActionButton actionButton;
FrameLayout no_internet_container;
Bundle savedInstanceState;
// Attaching Handler to the main thread
Handler handler = new Handler();
boolean shouldHandlerRunAgain = true;
private ArrayList<DataModel> model;
/**
* Handler is attached to the Main Thread and it's message queue, because it is the one who created it.
* <p>
* Handler is responsible for checking every second that are we connected to internet, and if we are, then :-
* 1. Then we remove empty view
* 2. Make the network call
* 3. Stop handler from posting the code again using shouldHandlerRunAgain variable
* 3.1 This is a kill switch otherwise handler will post the runnable again and again to the message queue, which will be executed as soon as it reaches the looper
* <p>
* Handler removeCallbacks is used to remove all the pending runnables in the Message Queue
*/
Runnable job = new Runnable() {
#Override
public void run() {
Log.d(TAG, "Thread run " + job.hashCode());
swapViews();
if (shouldHandlerRunAgain)
handler.postDelayed(job, HANDLER_DELAY_TIME);
}
};
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString("ORDER_BY", order_By);
}
#Override
public void onResume() {
super.onResume();
if (handler != null)
handler.post(job);
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "Starting Handler");
layoutManager = new GridLayoutManager(getContext(), 2);
scrollListener = new EndlessRecyclerViewScrollListener(layoutManager) {
public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
Log.w(TAG, "On load More Called with page number " + page);
loadDataUsingVolley(page, order_By);
}
};
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.search:
Toast.makeText(getContext(), "Async task", Toast.LENGTH_SHORT).show();
break;
default:
Toast.makeText(getContext(), "Invalid Options", Toast.LENGTH_SHORT).show();
}
return true;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_page_fragment, menu);
}
private void swapViews() {
if (detectConnection(getContext()) == false) {
recyclerView.setVisibility(View.INVISIBLE);
actionButton.setVisibility(View.INVISIBLE);
no_internet_container.setVisibility(View.VISIBLE);
} else {
Log.d(TAG, "Removing callbacks from handler and stopping it from posting");
shouldHandlerRunAgain = false;
handler.removeCallbacks(job, null);
handler = null;
recyclerView.setVisibility(View.VISIBLE);
actionButton.setVisibility(View.VISIBLE);
no_internet_container.setVisibility(View.INVISIBLE);
if (savedInstanceState != null) {
loadDataUsingVolley(1, savedInstanceState.getString("ORDER_BY"));
} else {
order_By = "latest";
loadDataUsingVolley(1, order_By);
}
}
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, final Bundle savedInstanceState) {
this.savedInstanceState = savedInstanceState;
View view = inflater.inflate(R.layout.fragment_page, container, false);
actionButton = (FloatingActionButton) view.findViewById(R.id.sort_button);
actionButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
SortDialog sortDialog = new SortDialog();
sortDialog.setTargetFragment(PageFragment.this, 911);
sortDialog.show(getChildFragmentManager(), "sortfragment");
}
});
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);
recyclerView.setHasFixedSize(true);
no_internet_container = (FrameLayout) view.findViewById(R.id.no_internet_container);
return view;
}
void setUpRecyclerView() {
if (imageAdapter == null)
imageAdapter = new ImageAdapter(getContext(), (model==null)?new ArrayList<DataModel>():model);
recyclerView.setAdapter(imageAdapter);
recyclerView.setLayoutManager(layoutManager);
recyclerView.addOnScrollListener(scrollListener);
}
void loadDataUsingVolley(int page, String order_by) {
final ProgressDialog dialog = ProgressDialog.show(getContext(), "Wallser", "Loading");
RequestQueue requestQueue = Volley.newRequestQueue(getContext());
String URL = "https://api.unsplash.com/photos/?page=" + page + "&client_id=" + api_key + "&per_page=" + per_page + "&order_by=" + order_by;
Log.d(TAG, URL);
JsonArrayRequest objectRequest = new JsonArrayRequest(Request.Method.GET, URL, null, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray array) {
int len = array.length();
if (model == null)
model = new ArrayList<>();
for (int i = 0; i < len; i++) {
try {
JSONObject object = array.getJSONObject(i);
String id = object.getString("id");
JSONObject object1 = object.getJSONObject("urls");
String imageURL = object1.getString("regular");
JSONObject object2 = object.getJSONObject("links");
String downloadURL = object2.getString("download");
model.add(new DataModel(imageURL, downloadURL, id));
Log.d(TAG, downloadURL);
} catch (JSONException e) {
e.printStackTrace();
}
}
if (dialog != null) {
dialog.dismiss();
}
Log.d(TAG, model.size() + "");
setUpRecyclerView();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
dialog.dismiss();
Toast.makeText(getContext(), "" + error.getMessage(), Toast.LENGTH_SHORT).show();
}
});
requestQueue.add(objectRequest);
}
/**
* marks a new network call to Unsplash API
* Thus, set model array list to null, to start fresh.
* as model is reset, ImageAdapter also needs to start fresh.
*
* #param order_by
*/
#Override
public void onDialogFinish(String order_by) {
model = null;
imageAdapter=null;
order_By = order_by;
loadDataUsingVolley(1, order_By);
}
}
I've found several questions about this, none of which help me. Each question relates to other functions and views I don't implement in my fragments, and the issue is not that I need to swap my method getting the FragmentManager to getChildFragmentManager() anywhere in my fragments, because I don't need to get a FragmentManager there.
I'm guessing that my issue stems from the fragments and not the FragmentTabHost in the main activity, but I am not really sure. At all. All I know is that when you page between tabs, the adapter content disappears, but not the fragment itself. All views are still functional, so the functionality of each fragment remains intact.
This issue popped up only after I added a tab change listener for when to initialize the adapter for my chat fragment.
Note that the content of the tabs is fine when they are first initialized, but when you return to the tab the content in the adapters empty. This means that the tab that is not initialized yet when the FragmentTabHost is created, the hidden tabs haven't been initialized yet, so they will still work the first time you page over to them.
Through debugging, I can see that this issue occurs when the transition happens, and all adapters will remain empty for the duration of the usage session. I put this snippit of code before the initial checks in my tabHost.setOnTabChangedListener call:
//Before paging back to an initialized tab for the first time, the adapters of the initialized tab is populated.
Log.d("test", "pre");
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
//At this point, the adapter is empty.
Log.d("test", "post");
}
}, 50);
The two fragments are as follows:
public class GroupTasksFragment extends Fragment {
public ArrayAdapter<String> adapter;
private Context context;
public ListView taskListView;
public GroupTasksFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_group_tasks, container, false);
taskListView = (ListView) rootView.findViewById(R.id.tasksList);
adapter = new ArrayAdapter<>(context, android.R.layout.simple_list_item_1, new ArrayList<String>());
taskListView.setAdapter(adapter);
return rootView;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.context = context;
}
#Override
public void onDetach() {
super.onDetach();
}
}
public class GroupChatFragment extends Fragment{
public ArrayAdapter<String> adapter;
private Context context;
public ListView chatListView;
public GroupChatFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_group_chat, container, false);
chatListView = (ListView) rootView.findViewById(R.id.chatList);
adapter = new ArrayAdapter<>(context, android.R.layout.simple_list_item_1, new ArrayList<String>());
chatListView.setAdapter(adapter);
return rootView;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.context = context;
}
#Override
public void onDetach() {
super.onDetach();
}
}
The main activity with the FragmentTabHost (I have excluded methods that just take input and send content to PubNub):
public class GroupContentActivity extends AppCompatActivity {
private GroupChatFragment chatFrag;
private GroupTasksFragment taskFrag;
private FragmentTabHost tabHost;
private PubNub connection;
private String groupName;
private String nickName;
private boolean chatFragInitialized = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_group_content);
tabHost = (FragmentTabHost) findViewById(android.R.id.tabhost);
tabHost.setup(this, getSupportFragmentManager(), android.R.id.tabcontent);
tabHost.addTab(tabHost.newTabSpec("tasks").setIndicator("Tasks"),
GroupTasksFragment.class, null);
tabHost.addTab(tabHost.newTabSpec("chat")
.setIndicator("Chat"), GroupChatFragment.class, null);
groupName = getIntent().getStringExtra("groupName");
nickName = getIntent().getStringExtra("nickName");
PNConfiguration config = new PNConfiguration();
config.setPublishKey(Constants.publishKey);
config.setSubscribeKey(Constants.subscribeKey);
connection = new PubNub(config);
tabHost.setOnTabChangedListener(new TabHost.OnTabChangeListener() {
#Override
public void onTabChanged(String tabId) {
if (!chatFragInitialized && tabId.equals("chat")) {
chatFragInitialized = true;
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
chatFrag = (GroupChatFragment) getSupportFragmentManager().findFragmentByTag("chat");
connection.history()
.channel(groupName)
.count(50)
.async(new PNCallback<PNHistoryResult>() {
#Override
public void onResponse(PNHistoryResult result, PNStatus status) {
for (PNHistoryItemResult item : result.getMessages()) {
final String[] sForm = item.getEntry().getAsString().split(">>>>");
String m = "";
if (sForm.length > 2) {
for (int x = 1; x < sForm.length; x++) {
m += sForm[x];
}
} else {
m = sForm[1];
}
final String mCopy = m;
runOnUiThread(new Runnable() {
#Override
public void run() {
switch (sForm[0]) {
case "groupCreated":
chatFrag.adapter.clear();
break;
case "chat":
chatFrag.adapter.add(mCopy);
}
}
});
}
}
});
}
}, 50);
}
}
});
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
taskFrag = (GroupTasksFragment) getSupportFragmentManager().findFragmentByTag("tasks");
connection.history()
.channel(groupName)
.count(50)
.async(new PNCallback<PNHistoryResult>() {
#Override
public void onResponse(PNHistoryResult result, PNStatus status) {
for (PNHistoryItemResult item : result.getMessages()) {
final String[] sForm = item.getEntry().getAsString().split(">>>>");
String m = "";
if (sForm.length > 2) {
for (int x = 1; x < sForm.length; x++) {
m += sForm[x];
}
} else {
m = sForm[1];
}
final String mCopy = m;
runOnUiThread(new Runnable() {
#Override
public void run() {
switch (sForm[0]) {
case "addTask":
if (taskFrag.adapter.getPosition(mCopy) < 0) {
taskFrag.adapter.add(mCopy);
}
break;
case "deleteTask":
if (taskFrag.adapter.getPosition(mCopy) >= 0) {
taskFrag.adapter.remove(mCopy);
}
break;
case "groupCreated":
taskFrag.adapter.clear();
break;
}
}
});
}
}
});
connection.addListener(new SubscribeCallback() {
#Override
public void status(PubNub pubnub, PNStatus status) {
if (status.getCategory() == PNStatusCategory.PNUnexpectedDisconnectCategory) {
Toast.makeText(getApplicationContext(), "You were disconnected!", Toast.LENGTH_SHORT).show();
} else if (status.getCategory() == PNStatusCategory.PNConnectedCategory) {
if (status.getCategory() == PNStatusCategory.PNConnectedCategory) {
pubnub.publish().channel(groupName).message("chat>>>><ADMIN> User '" + nickName + "' Connected").async(new PNCallback<PNPublishResult>() {
#Override
public void onResponse(PNPublishResult result, PNStatus status) {
}
});
}
} else if (status.getCategory() == PNStatusCategory.PNReconnectedCategory) {
Toast.makeText(getApplicationContext(), "You were reconnected!", Toast.LENGTH_SHORT).show();
}
}
#Override
public void message(PubNub pubnub, PNMessageResult message) {
final String[] sForm = message.getMessage().getAsString().split(">>>>");
String m = "";
if (sForm.length > 2) {
for (int x = 1; x < sForm.length; x++) {
m += sForm[x];
}
} else {
m = sForm[1];
}
final String mCopy = m;
runOnUiThread(new Runnable() {
#Override
public void run() {
switch (sForm[0]) {
case "chat":
if (chatFragInitialized) {
chatFrag.adapter.add(mCopy);
runOnUiThread(new Runnable() {
#Override
public void run() {
chatFrag.chatListView.setSelection(chatFrag.adapter.getCount() - 1);
}
});
}
break;
case "addTask":
taskFrag.adapter.add(mCopy);
connection.publish().channel(groupName).message("chat>>>><ADMIN> Task '" + mCopy + "' added.").async(new PNCallback<PNPublishResult>() {
#Override
public void onResponse(PNPublishResult pnPublishResult, PNStatus pnStatus) {
}
});
break;
case "deleteTask":
taskFrag.adapter.remove(mCopy);
connection.publish().channel(groupName).message("chat>>>><ADMIN> Task '" + mCopy + "' deleted.").async(new PNCallback<PNPublishResult>() {
#Override
public void onResponse(PNPublishResult pnPublishResult, PNStatus pnStatus) {
}
});
break;
}
}
});
}
#Override
public void presence(PubNub pubnub, PNPresenceEventResult presence) {
}
});
connection.subscribe().channels(java.util.Collections.singletonList(groupName)).execute();
}
}, 100);
}
#Override
public void onDestroy(){
super.onDestroy();
connection.publish().channel(groupName).message("chat>>>><ADMIN> User '" + nickName + "' Logged Out.").async(new PNCallback<PNPublishResult>() {
#Override
public void onResponse(PNPublishResult pnPublishResult, PNStatus pnStatus) {
}
});
connection.disconnect();
Toast.makeText(getApplicationContext(), "Logged out", Toast.LENGTH_SHORT).show();
}
//More Methods
}
Also note that the issue is not that I need to store the FragmentManager instance, as that doesn't do anything.
I found my issue. It turns out that every time a fragment is paged to in the FragmentTabHost, it's createView method is called again, and only that method, so by setting the adapter in the fragment to empty in that view, which I thought was only at the start, I reset the adapter each time.
I fixed this by keeping the adapter content as an instance variable list object that I add or remove strings to/from when I want to change the adapter. DO NOT ALSO PUT THE STRINGS IN THE ADAPTER, updating the list is enough. The list will directly add it to the adapter.
Also note that if you set the initial content outside of the fragment, it may not show when the tabs are first initialized. Just be careful of your statement ordering and when things are called. Fragment construction is funky business.
Then, I set the adapter to whatever is in the list each time the createView method is called.
I am fetching data from json with Volley and populating RecyclerView with the parsed data but I ran into a bit of problem:
The call to get the items is in onCreate method, so the call is repeated each time the activity is recreated both from configuration changes and otherwise; hence the data is reloaded. So I found this answer that uses parcelables
and this article on Codepath (still on parcelables). After I have followed the instructions explicitly (or so I feel), there seems to be no change: the call to get data is repeated each time the activity is recreated.
FruitItems
public class FruitItems implements Parcelable {
private String fruit_title;
private String fruit_description;
private String fruit_image;
public String getFruit_title() {
return fruit_title;
}
public void setFruit_title(String fruit_title) {
this.fruit_title = fruit_title;
}
public String getFruit_description() {
return fruit_description;
}
public void setFruit_description(String fruit_description) {
this.fruit_description = fruit_description;
}
public String getFruit_image() {
return fruit_image;
}
public void setFruit_image(String fruit_image) {
this.fruit_image = fruit_image;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(this.fruit_title);
dest.writeString(this.fruit_description);
dest.writeString(this.fruit_image);
}
public FruitItems() {
}
protected FruitItems(Parcel in) {
this.fruit_title = in.readString();
this.fruit_description = in.readString();
this.fruit_image = in.readString();
}
public static final Parcelable.Creator<FruitItems> CREATOR = new Parcelable.Creator<FruitItems>() {
#Override
public FruitItems createFromParcel(Parcel source) {
return new FruitItems(source);
}
#Override
public FruitItems[] newArray(int size) {
return new FruitItems[size];
}
};
}
MainActivity
public class MainActivity extends AppCompatActivity {
private final String TAG = "MainActivity";
private final String KEY_POST_ITEMS = "fruititems";
//List of fruits
private List<FruitItems> mFruitItemsList;
//Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private ProgressDialog mProgressDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.fruit_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
if (savedInstanceState != null && savedInstanceState.containsKey(KEY_POST_ITEMS)) {
mFruitItemsList = savedInstanceState.getParcelableArrayList(KEY_POST_ITEMS);
} else {
//Initializing the fruitlist
mFruitItemsList = new ArrayList<>();
if (NetworkCheck.isAvailableAndConnected(this)) {
getData();
} else {
final Context mContext;
mContext = this;
final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setTitle(R.string.alert_titl);
alertDialogBuilder.setCancelable(false);
alertDialogBuilder.setIcon(R.mipmap.ic_launcher);
alertDialogBuilder.setMessage(R.string.alert_mess);
alertDialogBuilder.setPositiveButton(R.string.alert_retry, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton(R.string.alert_cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
adapter = new FruitAdapter(mFruitItemsList, this);
recyclerView.setAdapter(adapter);
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putParcelableArrayList(KEY_POST_ITEMS, ArrayList<? extends Parcelable>))mFruitItemsList);
super.onSaveInstanceState(savedInstanceState);
}
//Getting json data
private void getData(){
Log.d(TAG, "getData called");
//Show progress dialog
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setCancelable(false);
mProgressDialog.setMessage(this.getResources().getString(R.string.load_fruit));
mProgressDialog.show();
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigFruit.GET_URL,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//parsing json data
private void parseData(JSONArray array){
Log.d(TAG, "Parsing array");
for(int i = 0; i<array.length(); i++) {
FruitItems fruitItem = new FruitItems();
JSONObject jsonObject = null;
try {
jsonObject = array.getJSONObject(i);
fruitItem.setFruit_title(jsonObject.getString(ConfigFruit.TAG_POST_TITLE));
fruitItem.setFruit_description(jsonObject.getString(ConfigFruit.TAG_POST_DESCRIPTION));
//Parsing image
JSONObject fruitImage = jsonObject.getJSONObject("thumbnail");
fruitItem.setFruit_image(fruitImage.getString("url"));
} catch (JSONException w) {
w.printStackTrace()
}
mFruitItemsList.add(fruitItem);
}
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
}
I may not be a pro but I know that I have goofed somewhere in the codes above, else it should have worked.
Now, my question is where did I goof and how do I plug this mistake?
EDIT
I have edited the codes above to reflect the answer that I accepted. It works fine but there is still a problem.
I start Activity B from MainActivity. If I press the back-button in Activity B the data is saved but when I press the up-button, the getData is called again and the data is re-fetched.
Please, is there anyway around this?
You don't seem to have an onSaveInstanceState in your mainactivity. You need something like
#Override
protected void onSaveInstanceState (Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelableArrayList(KEY_POST_ITEMS,mFruitItemsList) ;
}
In order to retain your data for the activity that is about to be destructed and the one that is being created, you need to override the onSaveInstance callback
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putParcelableArrayList(KEY_POST_ITEMS, (ArrayList)mFruitItemsList);
super.onSaveInstanceState(savedInstanceState);
}
NOTE: always remember to call the superclass.