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Cannot Cast Activity to Interface in fragment

my code has Class Cast Exception error.
When the string is sent from the adapter to the fragment by interface. In the fragment, the interface goes to the specific activity if the particular string is selected.
this is Interface code:
public interface StringListener {
void sendStr(String title);
}
and so this is adapter code:
public class StringRecyclerViewAdapter extends RecyclerView.Adapter<StringRecyclerViewAdapter.MyViewHolder>{
List<GridSubject> subjects;
Context context;
public StringRecyclerViewAdapter(Context context,List<GridSubject> subjects)
{
this.context=context;
this.subjects=subjects;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view;
LayoutInflater inflater=LayoutInflater.from(context);
view=inflater.inflate(R.layout.custom_layout,parent,false);
return new MyViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull MyViewHolder holder, int position) {
final GridSubject subject=subjects.get(position);
holder.txts.setText(subject.text);
holder.imgs.setImageResource(subject.drwab);
holder.myCard.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
sendStrMe(subject.getText());
}
});
}
#Override
public int getItemCount() {
return subjects.size();
}
public void sendStrMe(String title) {
StringListener listener=(StringListener) context;
listener.sendStr(title);
}
class MyViewHolder extends RecyclerView.ViewHolder{
TextView txts;
ImageView imgs;
CardView myCard;
public MyViewHolder(View itemView) {
super(itemView);
txts=itemView.findViewById(R.id.txt);
imgs=itemView.findViewById(R.id.img);
myCard=itemView.findViewById(R.id.my_card);
}
}
and this is Fragment Code:
public class FragmentA extends Fragment implements SportListener {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private String mParam1;
private String mParam2;
public Intent intent;
public FragmentA() {
// Required empty public constructor
}
public static FragmentA newInstance(String param1, String param2) {
FragmentA fragment = new FragmentA();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.my_layout_sport, container, false);
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
try {
super.onActivityCreated(savedInstanceState);
RecyclerView recyclerView=getView().findViewById(R.id.recycler_me);
final String[] txts={"Special","Hard","Manual","Easy"};
int[] imgs={R.drawable.special,R.drawable.hard,R.drawable.manual,R.drawable.easy};
List<GridSubject> subjects=new ArrayList<>();
for(int i=0;i<imgs.length;i++) {
subjects.add(new GridSubject(txts[i], imgs[i]));
}
int ori=getResources().getConfiguration().orientation;
int span;
if(ori== Configuration.ORIENTATION_LANDSCAPE)
span=3;
else
span=2;
StringRecyclerViewAdapter adapter=new StringRecyclerViewAdapter(getActivity(),subjects);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(),span));
recyclerView.setAdapter(adapter);
}
catch (Exception e)
{
Toast.makeText(getActivity().getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
#Override
public void onDetach() {
super.onDetach();
}
#Override
public void sendSport(String title) {
if(title=="Special") {
intent=new Intent(getActivity(),WebActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
else{
intent=new Intent(getActivity(),SportShowActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
startActivity(intent);
}
}
and this is Activity code:
public class MainActivity extends AppCompatActivity {
BottomNavigationView btm_navs;
FragmentA afrag;
FragmentB bfrag;
FragmentC cfrag;
FragmentD dfrag;
ViewPager pagerS;
MenuItem menuItem;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btm_navs = findViewById(R.id.btn_navs);
pagerS = findViewById(R.id.view_pager_mes);
btm_navs.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.item_a:
pagerS.setCurrentItem(0);
break;
case R.id.item_b:
pagerS.setCurrentItem(1);
break;
case R.id.item_c:
pagerS.setCurrentItem(2);
break;
case R.id.item_d:
pagerS.setCurrentItem(3);
break;
}
return true;
}
});
pagerS.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if (menuItem != null) {
menuItem.setChecked(false);
}
else {
btm_navs.getMenu().getItem(position).setChecked(false);
}
btm_navs.getMenu().getItem(position).setChecked(true);
menuItem = btm_navs.getMenu().getItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
setupViewPager();
}
catch (Exception e)
{
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
}
}
public void setupViewPager()
{
ViewPageradapter pageradapter=new ViewPageradapter(getSupportFragmentManager());
afrag=new FragmentA();
bfrag=new FragmentB();
cfrag =new FragmentC();
dfrag=new FragmentD();
pageradapter.addFragment(afrag);
pageradapter.addFragment(bfrag);
pageradapter.addFragment(cfrag);
pageradapter.addFragment(dfrag);
pagerS.setAdapter(pageradapter);
}
}
and so these are errors:
java.lang.ClassCastException: com.example.project.MainActivity cannot be cast to com.example.project.StringListener
at com.example.pakhkhsh.StringRecyclerViewAdapter.sendStrMe(StringRecyclerViewAdapter.java:56)
at com.example.pakhkhsh.StringRecyclerViewAdapter$1.onClick(StringRecyclerViewAdapter.java:45)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

Your activity needs to implement SportListener, not the fragment.
just do it:
public class MainActivity extends AppCompatActivity implements SportListener {
// your code ...
}```

Using only one Fragment with RecyclerView for multiple TabLayout , not updating data correctly on tabs change

There is a question similar to me, but that solution didn't work for my case.
The question I have referred is
this
I have a fragment named "HomeFragment" which consists of a VieWPager and TabLayout. I am adding tabs dynamically from the backend. So I am using another Fragment named "SecondFragment" for all tabs since all tabs contain a RecyclerView only. I am populating the RecyclerView onCreate() of the SecondFragment. My issue comes here that when I swipe or change the tab, the RecyclerView not updating correctly. On continuing swiping, the data changes but it does not correspond to the selected tab. I have logged the flow and I am getting correct data from backend on swiping, but it does not updating the RrecyclerView.
My HomeFragment class is
public class HomeFragment extends Fragment implements HTTPCallback {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private OnFragmentInteractionListener mListener;
private RecyclerView recyclerView;
private CardView cardview;
private boolean isShow;
View rootview;
private Toolbar toolbar;
private ImageView imageView, tabBg;
private CollapsingToolbarLayout collapsingToolbar;
private TabLayout mTabLayout;
Context context;
private ViewPager mViewPager, mViewPager1;
AppBarLayout appBarLayout;
Integer url_size;
int i;
boolean stopSliding = false;
String url, url2;
String message, version;
private ArrayList<HomeModel> planList;
JSONObject jsonObject, jsonObject2;
JSONArray jsonArray, jsonArray2;
ViewPagerAdapter adapter;
List<Product> products;
int numTab = 0;
private SharedPreferences sharedPreferences;
private SharedPreferences.Editor editor;
public HomeFragment() {
}
public static HomeFragment newInstance(String param1, String param2) {
HomeFragment fragment = new HomeFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootview = inflater.inflate(R.layout.fragment_home, container, false);
appBarLayout = (AppBarLayout) rootview.findViewById(R.id.appbar);
mViewPager1 = (ViewPager) rootview.findViewById(R.id.view_pager);
collapsingToolbar = (CollapsingToolbarLayout) rootview.findViewById(R.id.collapsing_toolbar);
sharedPreferences = getContext().getSharedPreferences("spade", Context.MODE_PRIVATE);
editor = sharedPreferences.edit();
mViewPager = (ViewPager) rootview.findViewById(R.id.viewpager);
mTabLayout = (TabLayout) rootview.findViewById(R.id.tabs);
mTabLayout.setSelectedTabIndicatorColor(Color.parseColor("#FF0000"));
mTabLayout.setSelectedTabIndicatorHeight((int) (5 * getResources().getDisplayMetrics().density));
mTabLayout.setTabTextColors(Color.parseColor("#727272"), Color.parseColor("#FF0000"));
new HTTPRequest(getContext(), null, null, HTTPRequest.METHOD.GET, this).execute(url2);
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if (position == 0) {
appBarLayout.setExpanded(true);
} else {
appBarLayout.setExpanded(false);
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
try {
} catch (Exception e) {
e.printStackTrace();
}
mTabLayout.setOnTabSelectedListener(
new TabLayout.ViewPagerOnTabSelectedListener(mViewPager) {
#Override
public void onTabSelected(TabLayout.Tab tab) {
super.onTabSelected(tab);
mViewPager.setCurrentItem(tab.getPosition());
numTab = tab.getPosition();
HomeModel browsePlan = planList.get(numTab);
editor.putString("tab", browsePlan.getName()).commit();
}
});
return rootview;
}
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onConnectionStarted() {
}
#Override
public void onConnectionFailed() {
}
#Override
public void onCompleted(JSONObject resultData) {
HomeModel model;
planList = new ArrayList<>();
adapter = new ViewPagerAdapter(getChildFragmentManager());
try {
jsonArray = resultData.getJSONArray("details");
editor.putString("tab", jsonArray.getJSONObject(0).getString("name"));
editor.commit();
for (int i = 0; i < jsonArray.length(); i++) {
jsonObject2 = jsonArray.getJSONObject(i);
model = new HomeModel();
model.setCatid(jsonObject2.getString("id"));
model.setImage(jsonObject2.getString("image"));
model.setName(jsonObject2.getString("name"));
planList.add(model);
setupViewPager(mViewPager, jsonObject2.getString("name"));
}
setAdapter();
} catch (JSONException e) {
e.printStackTrace();
}
}
private void setAdapter() {
appBarLayout.setExpanded(false);
mViewPager.setAdapter(adapter);
mTabLayout.setupWithViewPager(mViewPager);
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
private void setupViewPager(ViewPager mViewPager, String name) {
adapter.addFragment(new SecondFragment(), name);
mViewPager.setOffscreenPageLimit(1);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
SecondFragment class is
public class SecondFragment extends Fragment implements HTTPCallback {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
String mParam1;
String mParam2;
Button solo, grp;
View rootview;
Fragment fragment;
String url;
JSONObject jsonObject, jsonObject2;
JSONArray jsonArray, jsonArray2;
private ArrayList<Spaceship> planList;
RecyclerView rv;
private RecyclerHomeAdapter adapter = new RecyclerHomeAdapter(getContext(), planList);
;
private SharedPreferences sharedPreferences;
String tab_name;
private OnFragmentInteractionListener mListener;
public SecondFragment() {
}
public static SecondFragment newInstance(String s, String s1) {
SecondFragment fragment = new SecondFragment();
Bundle args = new Bundle();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootview = inflater.inflate(R.layout.fragment_second, container, false);
sharedPreferences = getContext().getSharedPreferences("spade", Context.MODE_PRIVATE);
tab_name = sharedPreferences.getString("tab", "onnumilla");
rv = (RecyclerView) rootview.findViewById(R.id.rv);
rv.setLayoutManager(new LinearLayoutManager(getContext()));
url = "My_url_here";
HashMap<String, String> data = new HashMap<String, String>();
data.put("name", tab_name);
new HTTPRequest2(getContext(), data, null, HTTPRequest2.METHOD.POST, this).execute(url);
return rootview;
}
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
adapter.notifyDataSetChanged();
// getFragmentManager().beginTransaction().detach(this).attach(this).commit();
}
}
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onConnectionStarted() {
}
#Override
public void onConnectionFailed() {
}
#Override
public void onCompleted(JSONObject resultData) {
Spaceship model;
planList = new ArrayList<>();
planList.clear();
try {
jsonArray = resultData.getJSONArray("products");
for (int i = 0; i < jsonArray.length(); i++) {
jsonObject2 = jsonArray.getJSONObject(i);
model = new Spaceship();
model.setName(jsonObject2.getString("package_name"));
model.setImage(jsonObject2.getString("images"));
planList.add(model);
}
setAdapter();
} catch (JSONException e) {
e.printStackTrace();
}
}
private void setAdapter() {
adapter = new RecyclerHomeAdapter(getContext(), planList);
adapter.notifyDataSetChanged();
rv.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
This doesn't work for me. But in the setUserVisibleHint(boolean isVisibleToUser) method when i add getFragmentManager().beginTransaction().detach(this).attach(this).commit();
instead of adapter.notifyDataSetChanged(); it works but it takes some time to hide previous data on swiping tab.
Anyone, please suggest me a solution. I have referred many questions but nothing works for me. All your response is appreciated.

This seems to be ViewPager page cashing issue. pls call below code from onCreateView()
of HomeFragment.
mViewPager.setOffscreenPageLimit(1);

RecyclerView in fragment through activity get position

so here is my problem, i have only one activity from i launch my viewpager fragment, in my viewpager i have 4 fragments containing recyclerViews. Every Fragment contains item populated by data on the net, when i click into one i get a WebView Fragment, but when i click on the backbutton i lost my poisiton, cause it's recreating the whole activity.
I don't know how to not recreate the activity and get back my old position, or recreating it but not changing the item's positions and have my old position back. Here's my code. Where i should put what ?! Some help would be very very well come.
Thank You !!
My Activity Class :
public class LauncherActivity extends AppCompatActivity implements ListFragment.OnNewSelectedInterface{
public static final String VIEWPAGER_FRAGMENT = "view_pager";
private ImageView mImageView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_launcher);
RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.activity_launcher);
mImageView = (ImageView) findViewById(R.id.logoImageView);
mImageView.startAnimation(AnimationUtils.loadAnimation(this, R.anim.rotate_indefinitely));
if(!isNetworkAvailable()){
alertUserAboutError();
} else {
relativeLayout.postDelayed(new Runnable() {
#Override
public void run() {
ViewPagerFragment savedFragment = (ViewPagerFragment)
getSupportFragmentManager().findFragmentByTag(VIEWPAGER_FRAGMENT);
if(savedFragment == null) {
ViewPagerFragment viewPagerFragment = new ViewPagerFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.activity_launcher, viewPagerFragment, VIEWPAGER_FRAGMENT);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
}
}, 2000);
}
}
#Override
public void onListNewSelected(int index, ArrayList<Articles> articles) {
WebViewFragment webViewFragment = new WebViewFragment();
Bundle bundle = new Bundle();
bundle.putInt(ViewPagerFragment.KEY_NEW_INDEX, index);
bundle.putParcelableArrayList(ListFragment.KEY_LIST, articles);
webViewFragment.setArguments(bundle);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.activity_launcher, webViewFragment, WebViewFragment.WEBVIEWFRAGMENT);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
private boolean isNetworkAvailable() {
ConnectivityManager manager = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if (networkInfo != null && networkInfo.isConnected()) {
isAvailable = true;
}
return isAvailable;
}
private void alertUserAboutError() {
AlertDialogFragment alertDialogFragment = new AlertDialogFragment();
alertDialogFragment.show(getFragmentManager(), "error_dialog");
}
}
My ViewPagerClass :
public class ViewPagerFragment extends Fragment {
public static final String KEY_NEW_INDEX = "key_new_index";
private ViewPager mViewPager;
private TabLayout mTabLayout;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.fragment_view_pager, container, false);
final OldFactFragment oldFactFragment = new OldFactFragment();
final SportFragment sportFragment = new SportFragment();
final BuzzFragment buzzFragment = new BuzzFragment();
final NewsFragment newsFragment = new NewsFragment();
mViewPager = (ViewPager) view.findViewById(R.id.viewPager);
mTabLayout = (TabLayout) view.findViewById(R.id.tabLayout);
mViewPager.setOffscreenPageLimit(4);
mViewPager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager()) {
#Override
public Fragment getItem(int position) {
if(position == 0){
return oldFactFragment;
} else if (position == 1) {
return newsFragment;
} else if (position == 2){
return sportFragment;
} else return buzzFragment;
}
#Override
public CharSequence getPageTitle(int position) {
if(position == 0){
return "Pastly";
} else if (position == 1) {
return "politic";
} else if (position == 2){
return "sport";
} else return "buzz";
}
#Override
public int getCount() {
return 4;
}
});
mTabLayout.setupWithViewPager(mViewPager);
return view;
}
}
My ListFragment(Parent's class of the 4 Fragments in the ViewPager) :
public abstract class ListFragment extends Fragment {
public static final String KEY_LIST = "key_list";
public interface OnNewSelectedInterface {
void onListNewSelected(int index, ArrayList<Articles> articles);
}
protected static final String TAG = ListFragment.class.getSimpleName();
protected ArrayList<Articles> mArticlesList;
protected ItemAdapter mArticleAdapter;
protected RecyclerView mRecyclerView;
protected OnNewSelectedInterface mListener;
protected RecyclerView.LayoutManager mManager;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
mListener = (OnNewSelectedInterface) getActivity();
View view = inflater.inflate(R.layout.fragment_list, container, false);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);
getInfos(getUrl());
return view;
}
protected abstract String[] getUrl();
private void getInfos(String[] url) {
if (isNetworkAvailable()) {
OkHttpClient client = new OkHttpClient();
for (int i = 0; i < getUrl().length; i++) {
Request request = new Request.Builder().url(url[i]).build();
client.newCall(request).enqueue(new Callback() {
#Override
public void onResponse(Call call, Response response) throws IOException {
try {
String jsonData = response.body().string();
if (response.isSuccessful()) {
Log.v(TAG, jsonData);
getMultipleUrls(jsonData);
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
getCurrentArticles(mArticlesList);
}
});
} else {
alertUserAboutError();
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
}
#Override
public void onFailure(Call call, IOException e) {
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
alertUserAboutError();
}
});
}
});
}
} else{
alertUserAboutError();
}
}
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesList == null) {
mArticlesList = getArticleForecast(jsonData);
} else {
mArticlesList.addAll(getArticleForecast(jsonData));
}
}
private void getCurrentArticles(ArrayList<Articles> articles) {
mArticleAdapter = new ItemAdapter(getActivity(), articles, mListener);
mRecyclerView.setAdapter(mArticleAdapter);
mManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mManager);
}
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 alertUserAboutError() {
AlertDialogFragment alertDialogFragment = new AlertDialogFragment();
alertDialogFragment.show(getActivity().getFragmentManager(), "error_dialog");
}
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;
}
}
And my ItemAdapter (Adapter Class) :
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ArticleViewHolder> {
private final ListFragment.OnNewSelectedInterface mListener;
protected ArrayList<Articles> mArticlesList;
protected Context mContext;
private int mPosition;
private int lastPosition = -1;
public ItemAdapter(Context contexts, ArrayList<Articles> mArticleLi, ListFragment.OnNewSelectedInterface listener){
mContext = contexts;
mArticlesList = mArticleLi;
mListener = listener;
}
#Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_linear, parent, false);
view.findViewById(R.id.textView).setSelected(true);
ArticleViewHolder articleViewHolder = new ArticleViewHolder(view);
articleViewHolder.setIsRecyclable(false);
return articleViewHolder;
}
#RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
#Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
mPosition = position;
holder.bindArticle(mArticlesList.get(position));
setAnimation(holder.itemView, position);
holder.mImageView.setClipToOutline(true);
}
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 class ArticleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener{
private TextView mTitle, mArticle;
private ImageView mImageView;
private ArticleViewHolder(View itemView) {
super(itemView);
mTitle = (TextView) itemView.findViewById(R.id.textView);
mArticle = (TextView) itemView.findViewById(R.id.showTextView);
mImageView = (ImageView) itemView.findViewById(R.id.imageView2);
itemView.setOnClickListener(this);
itemView.setOnLongClickListener(this);
}
private void bindArticle(Articles article) {
mTitle.setText(article.getTitle());
mArticle.setText(article.getDescription());
mArticle.setVisibility(View.INVISIBLE);
Glide.with(mContext).load(article.getImageView()).into(mImageView);
}
#Override
public void onClick(View view) {
mListener.onListNewSelected(getLayoutPosition(), mArticlesList);
}
#Override
public boolean onLongClick(View view) {
String desc = mArticlesList.get(getAdapterPosition()).getDescription();
mArticle.setVisibility(View.VISIBLE);
mArticle.setText(desc);
mArticle.postDelayed(new Runnable() {
public void run() {
mArticle.setVisibility(View.INVISIBLE);
}
}, 3000);
return true;
}
}
}

In Your method onListNewSelected You are Replacing the new fragment with the old one as stated in this line
fragmentTransaction.replace(R.id.activity_launcher, webViewFragment, WebViewFragment.WEBVIEWFRAGMENT);
From Google Documentaion
Replace an existing fragment that was added to a container. This is essentially the same as calling remove(Fragment) for all currently added fragments that were added with the same containerViewId and then add(int, Fragment, String) with the same arguments given here.
So you are removing the old Fragment then adding the new one, When you are back to get the old fragment, It is not already there it will be created from scratch, So the position is already gone with the removed fragment.
While using the add method, Will add the new fragment above the previous one, when you go back the previous one already there with its state "Position"

Update the row item data of recyclerview

The fragment consists of View Pager which shows the product count that
needs to be updated when the product is deleted or added .
public class SubCategoryFragment extends BaseFragment implements OnItemClickListener
{
private View rootView;
private MasterCategory subCategory;
private RecyclerView subCategoryRecyclerView;
private SubCategoryListAdapter subCategoryListAdapter;
private ArrayList<MasterCategory> superSubCategories;
private String iconImageURL;
private ArrayList<MerchantOrder> merchantorder;
/*private IRequestComplete iRequestComplete;*/
private int categoryId;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
super.onCreateView(inflater, container, savedInstanceState);
return rootView = inflater.inflate(R.layout.fragment_category_list, container, false);
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
initialiseUI();
}
initialise fragment
protected void initialiseUI()
{
categoryId = getArguments().getInt("categoryId");
iconImageURL = (String) getArguments().getSerializable("iconImageURL");
subCategory = (MasterCategory) getArguments().getSerializable("data");
subCategoryRecyclerView = (RecyclerView) rootView.findViewById(R.id.category_list_rc_view);
rootView.findViewById(R.id.dashboard_progressbar_newlyadded).setVisibility(View.GONE);
subCategoryRecyclerView.setHasFixedSize(true);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(context);
subCategoryRecyclerView.setLayoutManager(mLayoutManager);
superSubCategories = subCategory.getCategories();
rootView.findViewById(R.id.dashboard_progressbar_newlyadded).setVisibility(View.GONE);
if (superSubCategories != null && !superSubCategories.isEmpty())
{
subCategoryListAdapter = new SubCategoryListAdapter(superSubCategories, iconImageURL);
subCategoryRecyclerView.setAdapter(subCategoryListAdapter);
subCategoryListAdapter.setmOnItemClickListener(this);
updateListView();
}
else
{
rootView.findViewById(R.id.text_no_order_error).setVisibility(View.VISIBLE);
((TextView) rootView.findViewById(R.id.text_no_order_error)).setText("No Category found!");
}
}
Update the listview
private void updateListView()
{
if (subCategoryListAdapter == null)
{
subCategoryListAdapter = new SubCategoryListAdapter(superSubCategories,iconImageURL);
subCategoryRecyclerView.setAdapter(subCategoryListAdapter);
}
else
{
subCategoryListAdapter.notifyDataSetChanged();
}
subCategoryListAdapter.notifyDataSetChanged();
}
the itemclick opens up a fragment which displays the product details
#Override
public void onItemClick(View view, int position)
{
/*MasterCategory superSubCategories = subCategoryListAdapter.getSuperSubCategory(position);
Bundle bundle = new Bundle();
bundle.putSerializable("data", superSubCategories);
SuperSubCategoryProductsFragment superSubCategoryProductsFragment = new SuperSubCategoryProductsFragment();
superSubCategoryProductsFragment.setArguments(bundle);
manageFragment(superSubCategoryProductsFragment, SuperSubCategoryProductsFragment.class.getName(), CategoryDetailsFragment.class.getName(), bundle);*/
/*ArrayList<MasterCategory> superSubCategories = subCategoryListAdapter.getSuperSubCategory(position).getCategories();
if (null != superSubCategories){
Bundle bundle = new Bundle();
bundle.putSerializable("data", superSubCategories);
SuperSubCategoryListFragment categoryDetailsFragment = new SuperSubCategoryListFragment();
categoryDetailsFragment.setArguments(bundle);
manageFragment(categoryDetailsFragment, SuperSubCategoryListFragment.class.getName(), SubCategoryFragment.class.getName(), null);
}*/
MasterCategory superSubCategories = subCategoryListAdapter.getSuperSubCategory(position);
superSubCategories.getSubCategoryCount();
superSubCategories.getProductCount();
subCategoryListAdapter.notifyDataSetChanged();
if (superSubCategories.isHasChildCategory())
{
Bundle bundle = new Bundle();
bundle.putSerializable("data", superSubCategories);
Intent intent = new Intent(context, BaseFragmentActivity.class);
intent.putExtra("toolbarTitle", superSubCategories.getName());
intent.putExtra("FragmentClassName", SuperSubCategoryFragment.class.getName());
intent.putExtra("data", bundle);
startActivity(intent);
}
else
{
Intent intent = new Intent(context, BaseFragmentActivity.class);
Bundle bundle = new Bundle();
bundle.putInt("categoryId", superSubCategories.getCategoryId());
bundle.putString("categoryName", superSubCategories.getName());
bundle.putBoolean("isSubCatProducts", !superSubCategories.isHasChildCategory());
bundle.putInt("ProductCount", superSubCategories.getProductCount());
intent.putExtra("toolbarTitle", superSubCategories.getName());
intent.putExtra("FragmentClassName", SubCategoryProductsFragment.class.getName());
intent.putExtra("data", bundle);
startActivity(intent);
}
}
#Override
public void onPause()
{
super.onPause();
}
#Override
public void onResume()
{
super.onResume();
}
#Override
public void onAttachedToRecyclerView(RecyclerView recyclerView)
{
super.onAttachedToRecyclerView(subCategoryRecyclerView);
subCategoryRecyclerView.getAdapter().notifyDataSetChanged();
}
}
This is my Adapter attached to the fragment
public class SubCategoryListAdapter extends RecyclerView.Adapter<SubCategoryListAdapter.ViewHolder> implements View.OnClickListener {
private static final String TAG = SubCategoryListAdapter.class.getSimpleName();
private ArrayList<MasterCategory> superSubCategories;
private ImageLoader imageloader;
private com.amoda.androidlib.intf.OnItemClickListener mOnItemClickListener;
private String iconImageURL;
#Override
public void onClick(View view)
{
if (mOnItemClickListener != null)
mOnItemClickListener.onItemClick(view, (Integer) view.getTag());
}
public class ViewHolder extends RecyclerView.ViewHolder
{
public TextView name;
public TextView productCount;
public NetworkImageView image;
public ViewHolder(View itemLayoutView)
{
super(itemLayoutView);
productCount = (TextView) itemLayoutView.findViewById(R.id.product_count);
name = (TextView) itemLayoutView.findViewById(R.id.name);
image = (NetworkImageView) itemLayoutView.findViewById(R.id.image);
}
}
public SubCategoryListAdapter(ArrayList<MasterCategory> superSubCategories, String iconImageURL)
{
this.superSubCategories = superSubCategories;
imageloader = Global.getInstance().getImageLoader();
this.iconImageURL = iconImageURL;
}
#Override
public SubCategoryListAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.super_category_list_row, parent, false);
ViewHolder vh = new ViewHolder(v);
return vh;
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int position)
{
holder.name.setText("" + superSubCategories.get(position).getName());
holder.image.setDefaultImageResId(R.drawable.logo_amoda);
holder.image.setImageUrl(iconImageURL, imageloader);
if(!superSubCategories.get(position).isHasChildCategory())
{
holder.productCount.setText("" + superSubCategories.get(position).getProductCount());
}
else
{
holder.productCount.setText("");
holder.productCount.setBackgroundResource(R.drawable.icn_right_arrow);
}
holder.itemView.setTag(position);
holder.itemView.setOnClickListener(this);
}
public void setmOnItemClickListener(com.amoda.androidlib.intf.OnItemClickListener mOnItemClickListener)
{
this.mOnItemClickListener = mOnItemClickListener;
}
#Override
public int getItemCount()
{
if (superSubCategories != null)
return superSubCategories.size();
else
return 0;
}
public MasterCategory getSuperSubCategory(int position)
{
return superSubCategories.get(position);
}
}
This is my View pager in my activity
private void showSubCategoryTabs()
{
setToolbarTitle(category != null ? category.getName() : "");
try
{
mPromotionalImage.setDefaultImageResId(R.drawable.nodeals_img);
mPromotionalImage.setImageUrl(category.getImageUrl(), imageLoader);
}
catch (Exception e)
{
e.printStackTrace();
}
tabContent = new ArrayList<String>();
for (MasterCategory subCategories : category.getCategories())
{
/*Check if the sub-sub category has super-sub category or not.*/
if (null != subCategories.getCategories())
tabContent.add(subCategories.getName());
}
mViewPager.setAdapter(mSectionsPagerAdapter);
final TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener()
{
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
{
}
#Override
public void onPageSelected(int position)
{
Fragment fragment = ((SectionsPagerAdapter) mViewPager.getAdapter()).getFragment(position);
if (fragment != null)
{
fragment.onResume();
}
}
#Override
public void onPageScrollStateChanged(int state)
{
}
});
}
public class SectionsPagerAdapter extends FragmentStatePagerAdapter
{
private SectionsPagerAdapter sectionspageradapter;
private FragmentManager fragmentManager=null;
private Bundle bundle=new Bundle();
public SectionsPagerAdapter(FragmentManager fm)
{
super(fm);
fragmentManager=fm;
}
#Override
public Object instantiateItem(ViewGroup container,int position)
{
Object obj=super.instantiateItem(container,position);
if(obj instanceof Fragment)
{
Fragment f=(Fragment)obj;
String tag=f.getTag();
f.onResume();
}
return obj;
}
#Override
public Fragment getItem(int position)
{
MasterCategory subCategories = category.getCategories().get(position);
if (subCategories.isHasChildCategory())
{
SubCategoryFragment subCategoryFragment = new SubCategoryFragment();
Bundle bundle = new Bundle();
bundle.putSerializable("iconImageURL", category.getIconImageUrl());
bundle.putSerializable("data", category.getCategories().get(position));
subCategoryFragment.setArguments(bundle);
return subCategoryFragment;
}
else
{
SubCategoryProductsFragment subCategoryProductsFragment = new SubCategoryProductsFragment();
Bundle bundle = new Bundle();
bundle.putInt("categoryId", subCategories.getCategoryId());
bundle.putString("categoryName", subCategories.getName());
bundle.putBoolean("isSubCatProducts", true);
subCategoryProductsFragment.setArguments(bundle);
return subCategoryProductsFragment;
}
}
#Override
public int getCount()
{
return tabContent.size();
}
#Override
public CharSequence getPageTitle(int position)
{
Locale l = Locale.getDefault();
return tabContent.get(position);
}
public Fragment getFragment(int position)
{
String tag = String.valueOf(mMerchantSubCategories.get(position));
return fragmentManager.findFragmentByTag(tag);
}
}
#Override
public void onResume()
{
if (!EventBus.getDefault().isRegistered(this))
EventBus.getDefault().register(this);
super.onResume();
}
#Override
protected void onPause()
{
super.onPause();
}
#Override
public void onStop()
{
super.onStop();
//*Unregister event bus when the app goes in background*//*
if (EventBus.getDefault().isRegistered(this))
EventBus.getDefault().unregister(this);
}
#Override
public void onDestroy()
{
super.onDestroy();
if (EventBus.getDefault().isRegistered(this))
EventBus.getDefault().unregister(this);
}
public void onError(VolleyError volleyError)
{
UIHelper.stopProgressDialog(mProgressDialog);
Functions.Application.VolleyErrorCheck(this, volleyError);
}

just add this method to your viewPager adapter and your problem is solved.
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
this is override method of viewPager.
when you swipe one fragment to another it will automatically refresh page.

try this approach.. maybe its work for you..
put this code in your SubCategoryListAdepter
public void delete(int position) { //removes the row
superSubCategories.remove(position);
notifyItemRemoved(position);
}
make onClickListener to your ViewHolder:
suppose you click on your text and this row will be deleted.
#Override
public void onClick(View v) {
if(v.getId() == R.id.name){
//calls the method above to delete
delete(getAdapterPosition());
}
now you can also add data like this way.. thats working fine at runtime.. no need to refresh your page.

ViewPagerAdapter update fragment when starting again

I have the following ViewPagerAdapter:
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(((AppCompatActivity)getActivity()).getSupportFragmentManager());
adapter.addFrag(new OwnerPendingBookingsFragment(), "Pendientes");
adapter.addFrag(new OwnerConfirmedBookingsFragment(), "Confirmados");
adapter.addFrag(new OwnerFinishedBookingsFragment(), "Finalizados");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
And one of the fragments that I use is like that:
public class OwnerConfirmedBookingsFragment extends Fragment {
private View myView;
private ListView booking_list;
private ArrayAdapter adapter;
private SharedPreferences preferences;
private Toast toast;
private ProgressDialog progressDialog;
private BookingList bookings;
private boolean isFirstTime;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (isFirstTime) {
myView = inflater.inflate(R.layout.owner_confirmed_bookings_layout, container, false);
isFirstTime = false;
}
return myView;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
isFirstTime = true;
//Getting out sharedpreferences
preferences = getActivity().getSharedPreferences(Config.SHARED_PREF_LOGIN, Context.MODE_PRIVATE);
new FindBookings().execute("");
}
private void setUpAdapter(){
booking_list = (ListView) myView.findViewById(R.id.owner_confirmed_bookings);
getActivity().setTitle("Nuevas solicitudes");
if(bookings.getBookings().size() == 0){
booking_list.setVisibility(View.GONE);
LinearLayout no_vehicles = (LinearLayout) myView.findViewById(R.id.no_confirmed_bookings_layout);
no_vehicles.setVisibility(View.VISIBLE);
}else {
for (int i = 0; i < bookings.getBookings().size(); i++){
try {
new setImageTask(i).execute(bookings.getBookings().get(i).getDriver_image()).get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
adapter = new OwnerFinishedBookingsAdapter(myView.getContext(), bookings.getBookings());
booking_list.setAdapter(adapter);
booking_list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int booking_line = bookings.getBookings().get(position).getBooking_line_id();
Fragment booking_info = new OwnerPendingBookingInfoFragment();
Bundle args = new Bundle();
args.putInt("bookingLine", booking_line);
booking_info.setArguments(args);
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.content_frame, booking_info);
transaction.addToBackStack(null);
transaction.commit();
}
});
}
}
private class FindBookings extends AsyncTask<String, Void, String> {
String token = preferences.getString(Config.TOKEN, "");
#Override
protected void onPreExecute() {
toast = Toast.makeText(getActivity().getApplicationContext(), "", Toast.LENGTH_LONG);
progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage(getActivity().getString(R.string.finding_bookings));
progressDialog.show();
}
#Override
protected void onPostExecute(String s){
if(bookings.getError() != 0){
if(bookings.getError() == Config.JWT_EXPIRED){
logout();
Toast.makeText(getActivity().getApplicationContext(),
getActivity().getString(R.string.session_expired),
Toast.LENGTH_LONG).show();
}else {
toast.setText(getActivity().getString(R.string.find_pendings_errror));
toast.show();
}
}else {
setUpAdapter();
}
progressDialog.dismiss();
}
#Override
protected String doInBackground(String... params) {
bookings = DBConnect.getPendingBookingList(preferences.getInt(Config.IDUSER, 0), token);
return "done";
}
}
The first time I use it, all the fragments loads without any problem. But when I go to another activity and then return it doesn't update the data. I debug it and onCreate and onCreateView are not firing?
I tried to remove the fragment when going to another activity but nothing worked for me.