Develop Reference

Navigates to second fragment again by pressing back button previous data exists

I have two fragments and one activity (Main Activity). Now when I go from fragment 1 to fragment 2 data in fragment 2 loads from api. But when I press back button, navigates to fragment 1 and again I go from fragment 1 to fragment 2 then the previous loaded data is there for some secs and then fragment loads new data. Why it is so? I want that whenever I go to the fragment 2 it should reload again all the data (without showing the previous data for some secs first). Which method I should use?
Here is my onclick method from fragment 1 for navigating to fragment 2.
private void bind(FragmentUserInputFormBinding binding) {
binding.btnFetchOffer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
isAllFieldChecked = validateAllFields(binding);
if (isAllFieldChecked) {
Bundle bundle = new Bundle();
bundle.putString("appid", binding.etAppId.getText().toString());
bundle.putString("uid", binding.etUserId.getText().toString());
bundle.putString("token", binding.etToken.getText().toString());
OfferWallListFragment offerWallListFragment = new OfferWallListFragment();
offerWallListFragment.setArguments(bundle);
requireActivity().getSupportFragmentManager().beginTransaction()
.replace(((ViewGroup) requireView().getParent()).getId(), offerWallListFragment,"offerListFragment")
.setReorderingAllowed(true)
.addToBackStack("offerListFragment")
.commit();
}
}
});
}
Now I have my second fragment designed as follows fragment 2.
#AndroidEntryPoint
public class OfferWallListFragment extends BaseFragment<FragmentOfferWallListBinding> {
private RecyclerViewAdapter recyclerViewAdapter;
private int currentPage = FIRST_PAGE;
public OfferWallListFragment() {
// Required empty public constructor
}
#Override
public void onViewCreated(#NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Objects.requireNonNull(((AppCompatActivity) requireActivity()).getSupportActionBar()).setTitle("Offers List");
initViewModel(FragmentOfferWallListBinding.bind(view));
}
#NonNull
#Override
protected FragmentOfferWallListBinding initBinding(#NonNull LayoutInflater inflater, #Nullable ViewGroup container) {
return FragmentOfferWallListBinding.inflate(inflater, container, false);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_offer_wall_list, container, false);
}
private void initViewModel(FragmentOfferWallListBinding binding) {
OfferWallViewModel offerWallViewModel = new ViewModelProvider(this).get(OfferWallViewModel.class);
offerWallViewModel.getLiveData(currentPage).observe(getViewLifecycleOwner(), new Observer<OfferResponse>() {
#Override
public void onChanged(OfferResponse offerResponse) {
if (offerResponse != null) {
recyclerViewAdapter = new RecyclerViewAdapter();
recyclerViewAdapter.setOfferResponse(offerResponse);
binding.rvOfferData.setHasFixedSize(true);
binding.rvOfferData.setLayoutManager(new LinearLayoutManager(getContext()));
binding.rvOfferData.setAdapter(recyclerViewAdapter);
binding.rvOfferData.setVisibility(View.VISIBLE);
}
RecyclerViewPaginator recyclerViewPaginator = new RecyclerViewPaginator(binding.rvOfferData) {
#Override
public boolean isLastPage() {
return currentPage == offerResponse.getPages();
}
#Override
public void loadMore(int _currentPage) {
currentPage = _currentPage;
offerWallViewModel.getLiveData(Math.toIntExact(_currentPage));
}
};
binding.rvOfferData.addOnScrollListener(recyclerViewPaginator);
}
});
offerWallViewModel.getNetworkStateMutableLiveData().observe(getViewLifecycleOwner(), new Observer<NetworkState>() {
#Override
public void onChanged(NetworkState networkState) {
if (networkState == NetworkState.Companion.getLOADING()) {
binding.pbLoadingItems.setVisibility(View.VISIBLE);
} else if (networkState == NetworkState.Companion.getERROR()) {
Toast.makeText(getContext(), "Something went wrong, please check the parameters are filled perfectly", Toast.LENGTH_SHORT).show();
if (!CheckInternetConnection.isInternetAvailable(getContext())) {
Toast.makeText(getContext(), "No Internet Connection Available", Toast.LENGTH_SHORT).show();
binding.txtNoConnection.setText("No Internet Connection Available");
binding.txtNoConnection.setVisibility(View.VISIBLE);
}
binding.pbLoadingItems.setVisibility(View.GONE);
} else {
binding.pbLoadingItems.setVisibility(View.GONE);
}
}
});
}
}
Also I have handled onBackPressed method from MainActivity as follows.
#AndroidEntryPoint
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMainBinding binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.fragmentContainerView);
if (navHostFragment != null) {
NavController navController = navHostFragment.getNavController();
AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
R.id.userInputFormFragment, R.id.offerWallListFragment
).build();
NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
}
}
#Override
public void onBackPressed(){
int count = getSupportFragmentManager().getBackStackEntryCount();
if(count == 0) {
super.onBackPressed();
} else {
getSupportFragmentManager().popBackStack();
}
}
}
Please have a look on it ?

Exoplayer multiple instances when loading new fragments

I am creating a radio streaming app for a friend. I decided go down the Exo player route. Everything works fine, apart from if I load a new fragment or turn the screen round. Then I get a new instance of Exo player that starts behind the original. It can get really messy - how can I avoid this?
Here is my code. I open the fragment using:
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
root = inflater.inflate(R.layout.fragment_home, container, false);
initializeUIElements(root);
return root;
}
This is how I call Exo player:
private void initializeUIElements(View root) {
playSeekBar = root.findViewById(R.id.progressBar1);
playSeekBar.setMax(100);
playSeekBar.setVisibility(View.INVISIBLE);
}
#Override
public void onStop() {
super.onStop();
if (Util.SDK_INT >= 24) {
initializeMediaPlayer(root);
}
}
private void initializeMediaPlayer(View root) {
playerView = root.findViewById(R.id.video_view);
player = new SimpleExoPlayer.Builder(getContext()).build();
playerView.setPlayer(player);
MediaItem media = MediaItem.fromUri(revurl);
player.setMediaItem(media);
player.setPlayWhenReady(playWhenReady);
player.seekTo(currentWindow, playbackPosition);
player.prepare();
}
#Override
public void onPause() {
super.onPause();
if (Util.SDK_INT < 24) {
releasePlayer();
}
}
#Override
public void onStart() {
super.onStart();
if (Util.SDK_INT >= 24) {
initializeMediaPlayer(root);
}
}
#Override
public void onResume() {
super.onResume();
if ((Util.SDK_INT < 24 || player == null)) {
initializeMediaPlayer(root);
}
}
#SuppressLint("InlinedApi")
private void hideUi() {
playerView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
}
private boolean playWhenReady = true;
private int currentWindow = 0;
private long playbackPosition = 0;
private void releasePlayer() {
if (player != null) {
playWhenReady = player.getPlayWhenReady();
playbackPosition = player.getCurrentPosition();
currentWindow = player.getCurrentWindowIndex();
player.release();
player = null;
}
}
This is an example of the fragment I'm opening:
public class FacebookFragment extends Fragment {
Context c;
private WebView mwebview;
private String url = "https://www.facebook.com/Revotionofdance";
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.facebook_fragment, container, false);
mwebview = (WebView) root.findViewById(R.id.webview);
mwebview.setWebViewClient(new WebViewClient());
mwebview.addJavascriptInterface(new WebAppInterface(c), "Android");
WebSettings webSettings = mwebview.getSettings();
webSettings.setJavaScriptEnabled(true);
mwebview.loadUrl(url);
return root;
}
public class MyWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if ("https://www.facebook.com/Revotionofdance".equals(Uri.parse(url).getHost())) {
// This is my website, so do not override; let my WebView load the page
return false;
}
// Otherwise, the link is not for a page on my site, so launch another Activity that handles URLs
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(intent);
return true;
}
}
public class WebAppInterface {
Context mContext;
/**
* Instantiate the interface and set the context
*/
WebAppInterface(Context c) {
mContext = c;
}
/**
* Show a toast from the web page
*/
#JavascriptInterface
public void showToast(String toast) {
Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
}
}
This is my main activity where I call the fragments from:
DrawerLayout drawer = findViewById(R.id.drawer_layout);
NavigationView navigationView = findViewById(R.id.nav_view);
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
mAppBarConfiguration = new AppBarConfiguration.Builder(
R.id.nav_home, R.id.nav_facebook, R.id.nav_insta,R.id.nav_snap,R.id.nav_rodr)
.setDrawerLayout(drawer)
.build();
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
NavigationUI.setupWithNavController(navigationView, navController);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onSupportNavigateUp() {
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
return NavigationUI.navigateUp(navController, mAppBarConfiguration)
|| super.onSupportNavigateUp();
}

According to your code above currently in your onStop() method you initialise a new instance of SimpleExoPlayer instead of release it. You initialize the player in the onStart() or onResume() methods depending on the API level and release the created player in your onPause() or onStop() methods.
Currently you have:
#Override
public void onStop() {
super.onStop();
if (Util.SDK_INT >= 24) {
initializeMediaPlayer(root);
}
}
Change it to:
#Override
public void onStop() {
super.onStop();
if (Util.SDK_INT >= 24) {
releasePlayer();
}
}

If you have only instance ExoPlayer in whole app. You can using singleton pattern to provide instance ExoPlayer.
If you want only instance Exoplayer in each fragment. I recommend you using ViewModel to init and store ExoPlayer instance because ViewModel isn't reset when you add new fragment or rotate screen.

RecyclerView disappearing after switching between fragments on a particular Activity

The problem I have been facing with the development is that there is a recyclerview inside my fragment which gets disappeared after I switch between two fragments on a particular activity. On the first time when the fragment loads everything works fine but afterwards I don't understand what goes wrong. I had tried to refer to various ways that people had posted over github like notifyDatasetChanged, etc. But nothing seems to work. I would appreciate if someone could help me out with this issue.
So here are my classes.
The ProfileFragment.java :
public class ProfileFragment extends Fragment {
FirebaseAuth firebaseAuth;
FirebaseUser user;
FirebaseDatabase firebaseDatabase;
DatabaseReference databaseReference;
StorageReference storageReference;
RecyclerView itemRecycler;
List<ModelProfile> modelProfiles;
AdapterProfile adapterProfile;
String storagePath= "Users_Profile_Cover_Image/-";
ImageView avatarIv,dp;
CardView card,cardArrow;
TextView nameTv, emailTv, phoneTv;
Button logout,update;
ExtendedFloatingActionButton fab;
ProgressDialog pd;
//..
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view= inflater.inflate(R.layout.fragment_profile, container, false);
firebaseAuth = FirebaseAuth.getInstance();
user= firebaseAuth.getCurrentUser();
firebaseDatabase = FirebaseDatabase.getInstance();
databaseReference = firebaseDatabase.getReference("Users");
storageReference= getInstance().getReference();
loadItems();
return view;
}
private void loadItems() {
//Problem could be here
GridLayoutManager layoutManager= new GridLayoutManager(getContext(),3);
itemRecycler.setHasFixedSize(true);
itemRecycler.setLayoutManager(layoutManager);
itemRecycler.setVisibility(View.VISIBLE);
CollectionReference ref =FirebaseFirestore.getInstance().collection("All_Posts");
com.google.firebase.firestore.Query query = ref.whereEqualTo("uid",uid);
FirestoreRecyclerOptions<ModelProfile> options = new FirestoreRecyclerOptions.Builder<ModelProfile>()
.setQuery(query,ModelProfile.class).build();
adapterProfile = new AdapterProfile(options,getActivity());
itemRecycler.setAdapter(adapterProfile);
adapterProfile.startListening();
query.addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(#Nullable QuerySnapshot value,
#Nullable FirebaseFirestoreException e) {
if (e != null) {
return;
}
assert value != null;
Log.i("Size",String.valueOf(value.getDocuments().size()));
if (value.getDocuments().size() > 0) { // List is populated
card.setVisibility(View.GONE);
cardArrow.setVisibility(View.GONE);
} else { // List is empty
card.setVisibility(View.VISIBLE);
cardArrow.setVisibility(View.VISIBLE);
}
}
});
}
//
// #Override
// public void onStart() {
// super.onStart();
// adapterProfile.startListening();
// }
//
//
//
// #Override
// public void onStop() {
// super.onStop();
// adapterProfile.stopListening();
// }
#Override
public void onResume() {
super.onResume();
adapterProfile.startListening();
}
}
Adapter:-
public class AdapterProfile extends FirestoreRecyclerAdapter<ModelProfile,AdapterProfile.MyHolder> {
Context context;
public String im;
public AdapterProfile(#NonNull FirestoreRecyclerOptions<ModelProfile> options, Activity Context) {
super(options);
context = Context;
}
#Override
protected void onBindViewHolder(#NonNull MyHolder holder, int position, #NonNull ModelProfile model) {
String uid = model.getUid();
String uEmail =model.getuEmail();
}
#NonNull
#Override
public MyHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
//..
}
class MyHolder extends RecyclerView.ViewHolder{
//..
}
Activity on which Fragment switching takes place
public class LandingActivity extends AppCompatActivity {
FirebaseAuth firebaseAuth;
DatabaseReference userDbRef;
FirebaseUser user;
String uid,dp;
ChipNavigationBar chipNavigationBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_landing);
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new InventoryFragment()).commit();
bottomMenu();
}
private void bottomMenu() {
chipNavigationBar.setOnItemSelectedListener(new ChipNavigationBar.OnItemSelectedListener() {
//problem could be here as well.........
#Override
public void onItemSelected(int i) {
Fragment fragment=null;
switch(i) {
case R.id.bottom_nav_2:
fragment = new CltFragment();
break;
case R.id.bottom_nav_3:
fragment = new MaceFragment();
break;
case R.id.bottom_nav_profile:
fragment = new ProfileFragment();
break;
}
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,fragment).commit();
}
});
}
private void checkUserStatus()
{
FirebaseUser user= firebaseAuth.getCurrentUser();
if(user !=null)
{
uid=user.getUid();
}
else
{
startActivity(new Intent(LandingActivity.this,MainActivity.class));
finish();
}
}
#Override
public void onResume() {
//Problem could be here
super.onResume();
Intent intent = getIntent();
String frag = "";
if(intent.hasExtra("frag")) {
frag = intent.getExtras().getString("frag");
}
else
{
//..
}
switch(frag)
{
//..
case "ProfileFragment":
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new ProfileFragment()).commit();
chipNavigationBar.setItemSelected(R.id.bottom_nav_profile,true);
break;
}
}
}
Thanks for having looked at my Problem!

Try using this
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container,new InventoryFragment()).commit();
Instead of this
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new InventoryFragment()).commit();

FirebaseRecyclerAdapter OnItemClick from fragment to fragment

I'm using the firebaseRecyclerAdaper on a fragment and i want to open an item from de populated list from firebase and send the data to a new fragment. Can u guys tell me please how can i start the FragmentDetail from the onCLickListener on FragmentAllPosts and pass the PostModel parameter to it?
Main Activity:
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private static final String TAG = "TAG" ;
private FirebaseAuth firebaseAuth;
private DatabaseReference databaseReference , postsRef;
private StorageReference profileImgRef;
private CircleImageView circleImageViewMain;
private TextView nameEdtTxt, emailEdtTxt;
Fragment fragment= null;
private RecyclerView recyclerView;
private FloatingActionButton fab;
private ProgressDialog progressDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
progressDialog= new ProgressDialog(this);
progressDialog.setMessage("Please wait!");
progressDialog.setCanceledOnTouchOutside(false);
//Initialize Firebase modules
firebaseAuth=FirebaseAuth.getInstance();
databaseReference= FirebaseDatabase.getInstance().getReference().child("users");
postsRef= FirebaseDatabase.getInstance().getReference().child("posts");
profileImgRef= FirebaseStorage.getInstance().getReference();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View header = navigationView.getHeaderView(0);
circleImageViewMain = (CircleImageView) header.findViewById(R.id.circleImageHeader);
nameEdtTxt = (TextView) header.findViewById(R.id.txtName);
emailEdtTxt =(TextView)header.findViewById(R.id.txtEmail);
if (firebaseAuth.getCurrentUser()!=null){
LoadUserData(CheckUserDataBase());
}
ViewPager vp_pages= (ViewPager) findViewById(R.id.vp_pages);
PagerAdapter pagerAdapter=new FragmentAdapter(getSupportFragmentManager());
vp_pages.setAdapter(pagerAdapter);
TabLayout tbl_pages= (TabLayout) findViewById(R.id.tabs);
tbl_pages.setupWithViewPager(vp_pages);
tbl_pages.setTabTextColors(ColorStateList.valueOf(Color.parseColor("#FFFFFF")));
tbl_pages.setHorizontalScrollBarEnabled(true);
fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
fragment= new AddPostFrag();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction= fragmentManager.beginTransaction();
transaction.add(R.id.add_post_container, fragment).commit();
fab.hide();
}
});
}
class FragmentAdapter extends FragmentPagerAdapter {
public FragmentAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
return new FragmentAllPosts();
case 1:
return new FragmentLosts();
case 2:
return new FragmentFounds();
}
return null;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position){
//
//Your tab titles
//
case 0:return "All";
case 1:return "Losts";
case 2: return "Founds";
default:return null;
}
}
}
#Override
protected void onStart() {
super.onStart();
FirebaseUser user= firebaseAuth.getCurrentUser();
if (user == null){
SendUserToLogin();
} else {
CheckUserDataBase();
}
}
public static class PostsViewHolder extends RecyclerView.ViewHolder {
CircleImageView circleImageView;
ImageView imageView;
TextView authorNdate, location, description;
public PostsViewHolder(#NonNull View itemView) {
super(itemView);
circleImageView= itemView.findViewById(R.id.circleImageView_cv);
imageView= itemView.findViewById(R.id.imageView_cv);
authorNdate= itemView.findViewById(R.id.author_date_cv);
location = itemView.findViewById(R.id.location_cv);
description = itemView.findViewById(R.id.description_cv);
}
}
private void UpdateHome() {
}
private void LoadUserData(final String uid) {
try {
final File localFile =File.createTempFile("profile","png");
StorageReference filepath=profileImgRef.child(uid).child("profileImg/profile.png");
filepath.getFile(localFile)
.addOnSuccessListener(new OnSuccessListener<FileDownloadTask.TaskSnapshot>() {
#Override
public void onSuccess(FileDownloadTask.TaskSnapshot taskSnapshot) {
Picasso.get()
.load(localFile)
.placeholder(R.drawable.ic_account)
.into(circleImageViewMain);
}
}).addOnFailureListener(new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
Toast.makeText(MainActivity.this,
"Profile photo not found, please update your profile!",
Toast.LENGTH_SHORT).show();
SendUserToSetup();
}
});
} catch (IOException e) {
e.printStackTrace();
}
databaseReference.child(uid).child("userInfo").addValueEventListener(
new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.hasChild("name")){
String name = dataSnapshot.child("name").getValue().toString();
nameEdtTxt.setText(name);
String email = dataSnapshot.child("email").getValue().toString();
emailEdtTxt.setText(email);
} else {
Toast.makeText(MainActivity.this,
"Profile name does not exists, please update your profile",
Toast.LENGTH_SHORT).show();
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
}
);
}
#Override
protected void onStop() {
super.onStop();
}
private String CheckUserDataBase() {
final String userID =firebaseAuth.getCurrentUser().getUid();
databaseReference.addValueEventListener(
new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if (!dataSnapshot.child(userID).hasChild("userInfo")){
SendUserToSetup();
} else {
UpdateHome();
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
}
);
return userID;
}
private void SendUserToSetup() {
Intent i = new Intent(this,SetupActivity.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
}
private void SendUserToLogin() {
Intent i = new Intent(this,LoginActivity.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else if (getSupportFragmentManager().getBackStackEntryCount() >0)
{
getSupportFragmentManager().beginTransaction().remove(fragment).commit();
} else
{
super.onBackPressed();
}
fab.show();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
switch (id){
case R.id.nav_home:
super.onResume();
if (fragment!=null){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction= fragmentManager.beginTransaction();
transaction.remove(fragment).commit();
fab.show();
}
break;
case R.id.nav_profile:
super.onPause();
break;
case R.id.nav_my_posts:
super.onPause();
break;
case R.id.nav_messeges:
super.onPause();
break;
case R.id.nav_settings:
super.onPause();
break;
case R.id.nav_logout:
SendUserToLogin();
firebaseAuth.signOut();
break;
}
DrawerLayout drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Fragment with the FirebaseRecyclerAdapter
public class FragmentAllPosts extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
private DatabaseReference postsRef;
private Context context= getContext();
Fragment mFragment;
Bundle mBundle;
public FragmentAllPosts() {
// Required empty public constructor
}
public static FragmentAllPosts newInstance(String param1, String param2) {
FragmentAllPosts fragment = new FragmentAllPosts();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
private RecyclerView recyclerAllPosts;
private ProgressDialog progressDialog;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
progressDialog= new ProgressDialog(getActivity());
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_all_posts,container,false);
postsRef= FirebaseDatabase.getInstance().getReference().child("posts");
recyclerAllPosts= v.findViewById(R.id.recycler_all_posts);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
recyclerAllPosts.setLayoutManager(linearLayoutManager);
return v;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.context=context;
}
#Override
public void onStart() {
super.onStart();
progressDialog.show();
FirebaseRecyclerOptions<PostsModel> options=
new FirebaseRecyclerOptions.Builder<PostsModel>()
.setQuery(postsRef,PostsModel.class)
.setLifecycleOwner(this)
.build();
FirebaseRecyclerAdapter<PostsModel,PostsViewHolder> adapter=
new FirebaseRecyclerAdapter<PostsModel, PostsViewHolder>(options) {
#Override
protected void onBindViewHolder(#NonNull final PostsViewHolder holder, int position, #NonNull final PostsModel model) {
String processedTime= CalculateTime(model.getData());
Picasso.get().load(Uri.parse(model.getUserImg())).into(holder.circleImageView);
Picasso.get().load(Uri.parse(model.getImageUri())).into(holder.imageView);
holder.authorNdate.setText(model.getAuthor()+" updated "+processedTime);
holder.location.setText(model.getLocation());
holder.description.setText(model.getDescription());
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Fragment frag= new FragmentDetail();
getFragmentManager().beginTransaction().replace(R.id.add_post_container,frag)
.addToBackStack(null).commit();
}
});
}
#NonNull
#Override
public PostsViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view= LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.card_view,viewGroup,false );
PostsViewHolder viewHolder= new PostsViewHolder(view);
return viewHolder;
}
};
recyclerAllPosts.setAdapter(adapter);
progressDialog.dismiss();
adapter.startListening();
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
public String CalculateTime(String inputTime){
String timeOut;
Calendar currentTime= Calendar.getInstance();
SimpleDateFormat dateFormat= new SimpleDateFormat(getString(R.string.date_format));
dateFormat.format(currentTime.getTime());
SimpleDateFormat postFormat= new SimpleDateFormat(getString(R.string.date_format));
Calendar postTime = Calendar.getInstance();
try {
Date datePost=postFormat.parse(inputTime);
postTime.setTime(datePost);
} catch (ParseException e) {
e.printStackTrace();
}
long timeCurrent= currentTime.getTimeInMillis();
long timePost = postTime.getTimeInMillis();
long diff= timeCurrent- timePost;
long minutes= diff/(60*1000);
long hours = diff/(60 * 60 * 1000);
long days = diff/(24 * 60 * 60 * 1000);
if (minutes<59 && minutes>1){
timeOut=Long.toString(minutes)+" mins ago";
} else if (minutes<1){
timeOut=" just now";
}else if (hours<24 && minutes>59){
timeOut=Long.toString(hours)+" hour(s) ago";
}else {
timeOut=Long.toString(days)+" day(s) ago";
}
return timeOut;
}
static class PostsViewHolder extends RecyclerView.ViewHolder {
CircleImageView circleImageView;
ImageView imageView;
TextView authorNdate, location, description;
public PostsViewHolder(#NonNull View itemView) {
super(itemView);
itemView.setTag(this);
circleImageView= itemView.findViewById(R.id.circleImageView_cv);
imageView= itemView.findViewById(R.id.imageView_cv);
authorNdate= itemView.findViewById(R.id.author_date_cv);
location = itemView.findViewById(R.id.location_cv);
description = itemView.findViewById(R.id.description_cv);
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
Detail Fragment:
public class FragmentDetail extends Fragment {
public FragmentDetail() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_detail, container, false);
}
}

I'd suggest a read on the documentation. Passing data between two activities should be done via interfaces.
As suggested by the official site

Android list fragment not updated when configuration changes

I'm making a simple app that adds a location to the list fragment in main page, and as I add more addresses to the list, whenever configuration changes, those addresses are carried over, which is expected.
However as you will see below, the empty list text shows up for some reason, and seems like when I add another new address hereafter, it will add to the very first place of the list.
Below is my main activity :
public class MainActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {
private GoogleApiClient mGoogleApiClient;
private Location mLastLocation, mCurrentLocation;
private double currentLatitude, currentLongitude;
private String lastUpdateTime, addressMessage = null;
private AddressResultReceiver resultReceiver;
private MainList listFragment = new MainList();
//private boolean mRequestStatus = true;
private MaterialDialog dialog;
public boolean mAddressRequested = false;
private FragmentManager mFragmentManager;
private final String FRAGMENT_TAG = "main_list_tag";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addOnConnectionFailedListener(this)
.addConnectionCallbacks(this)
.build();
mFragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.add(R.id.list_frame, listFragment);
fragmentTransaction.commit();
dialog = new MaterialDialog(this)
.setTitle("Select an address")
.setPositiveButton("SELECT", new View.OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
listFragment.list.add(addressMessage);
listFragment.mAdapter.notifyDataSetChanged();
}
})
.setNegativeButton("CANCEL", new View.OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
Toolbar toolbar = (Toolbar) findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
FloatingActionButton floatingActionButton = (FloatingActionButton) findViewById(R.id.fab_button);
//LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
floatingActionButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (checkAirPlaneMode(getApplicationContext())) {
Toast.makeText(getApplicationContext(), "Air Plane Mode is ON, Please turn off to get location", Toast.LENGTH_LONG).show();
}
else if (!checkNetwork()) {
Toast.makeText(getApplicationContext(),"Unable to reach network, please check network settings",Toast.LENGTH_LONG).show();
}
else if (!checkLocationSettings(getApplicationContext())) {
showLocationSettings();
}
else {
startAddressLookUp();
mAddressRequested = true;
dialog.setMessage(addressMessage);
dialog.show();
}
}
});
}
#Override
public void onStart() {
super.onStart();
if (mGoogleApiClient == null) {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addOnConnectionFailedListener(this)
.addConnectionCallbacks(this)
.build();
}
mGoogleApiClient.connect();
}
#Override
protected void onPause() {
super.onPause();
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
#Override
public void onResume() {
super.onResume();
if(mGoogleApiClient.isConnected()) {
LocationRequest locationRequest = createLocationRequest();
startLocationUpdates(locationRequest);
}
}
And list fragment class:
public class MainList extends ListFragment implements AdapterView.OnItemClickListener {
private int stateInt;
private final String FRAGMENT_KEY = "saved_fragment";
ArrayList<String> list = new ArrayList<>();
ArrayAdapter<String> mAdapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.list_fragment, container, false);
/*ListView view = (ListView) v.findViewById(android.R.id.list);
view.setEmptyView(v.findViewById(android.R.id.empty));
return view;*/
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setRetainInstance(true);
getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
mAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, list);
setListAdapter(mAdapter);
//mAdapter.notifyDataSetChanged();
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(parent.getContext(), "Item Pressed!", Toast.LENGTH_LONG).show();
}
}
How can avoid this? Am I missing the save application state or something else? Any help would be appreciated! Thanks in advance!
Thanks,
Paul

The onCreate method is called for every orientation change. And in the method you are adding the fragment again. That is why you get this behavior.
Check this for the correct way to do this.
Handling Configuration Changes with Fragments
FragmentManager fm = getFragmentManager();
mTaskFragment = (TaskFragment) fm.findFragmentByTag(TAG_TASK_FRAGMENT);
// If the Fragment is non-null, then it is currently being
// retained across a configuration change.
if (mTaskFragment == null) {
mTaskFragment = new TaskFragment();
fm.beginTransaction().add(mTaskFragment, TAG_TASK_FRAGMENT).commit();
}