Develop Reference

how to retrive a list from the firebase database

this is my db structure
I have a list of passenger and i want to retrive them from the firebase database if the passenger list contains more than one passenger then i want to get those data show in one textView. But everytime it generates 2 textView if there were two passenger. I want in all cases it shows all the data in just one TextView.
This is my model Class`
public class RetrieveTickets {
private String name;
private String age;
private String gender;
public RetrieveTickets() {
}
public RetrieveTickets(String name, String age, String gender) {
this.name = name;
this.age = age;
this.gender = gender;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public List<HashMap<String,Object>> toList(){
List<HashMap<String,Object>> list=new ArrayList<>();
HashMap<String,Object> map=new HashMap<>();
map.put("name",getName());
map.put("age",getAge());
map.put("gender",getGender());
list.add(map);
return list;
}
}
this is MyActivity where i am showing the data
public class MyBookingsActivity extends AppCompatActivity{
private RecyclerView recyclerView;
private DatabaseReference databaseReference;
private FirebaseAuth mAuth;
private FirebaseRecyclerAdapter<RetrieveTickets, BookingHolder> firebaseRecyclerAdapter;
public static List<String> trips=new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_bookings);
recyclerView = (RecyclerView) findViewById(R.id.my_bookings);
recyclerView.setHasFixedSize(true);
String tripId = getIntent().getStringExtra("TripId");
trips.add(tripId);
// String bookingId = getIntent().getStringExtra("BookingId");
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mAuth = FirebaseAuth.getInstance();
FirebaseUser user = mAuth.getCurrentUser();
String userId = user.getUid();
databaseReference = FirebaseDatabase.getInstance().getReference();
Query query = databaseReference.child("BooKings").child(userId).child(tripId).child("passenger");
FirebaseRecyclerOptions<RetrieveTickets> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<RetrieveTickets>()
.setQuery(query, RetrieveTickets.class)
.build();
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<RetrieveTickets, BookingHolder>(firebaseRecyclerOptions) {
#Override
protected void onBindViewHolder(#NonNull BookingHolder holder, int position, #NonNull RetrieveTickets model) {
holder.setPassengers(model);
}
#NonNull
#Override
public BookingHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.tickets, parent, false);
return new BookingHolder(view);
}
#Override
public void onError(#NonNull DatabaseError error) {
super.onError(error);
Toast.makeText(MyBookingsActivity.this,"error"+error,Toast.LENGTH_LONG).show();
}
};
recyclerView.setAdapter(firebaseRecyclerAdapter);
}
#Override
protected void onStart() {
super.onStart();
firebaseRecyclerAdapter.startListening();
}
#Override
protected void onStop() {
super.onStop();
if (firebaseRecyclerAdapter != null) {
firebaseRecyclerAdapter.stopListening();
}
}
public static class BookingHolder extends RecyclerView.ViewHolder{
private TextView passenger;
public BookingHolder(#NonNull View itemView) {
super(itemView);
passenger=(TextView)itemView.findViewById(R.id.passenger);
}
void setPassengers(RetrieveTickets retrieveTickets) {
passenger.setText(retrieveTickets.toList().toString());
}
}

If you want to display all passengers in one TextView then you shouldn't do like this... Right now you are using RecyclerView and it will make rows == number of passengers and its exactly why we use RecyclerView
If you want to show PassengerList in one textView do like this
StringBuilder passengerStrBuilder = new StringBuilder();
for (String details : yourList) {
passengerStrBuilder.append(details + "\n");
}
textView.setText(passengerStrBuilder.toString());
Here yourList is Passenger List

Fetching data using retrofit2 and saving in room

I am using retrofit2 for fetching data from the server and after fetching saving data in room database and then showing in recycler view.Whenever app runs its fetches data from the server and save it in room database.I have successfully fetched JSON data from server and saved in room database and from room it is properly showing in recycler view.
Problem: Whenever data fetches from the server it inserts the same old data in room again due to which same data shows multiple times in recycler view.
What I want: I don't want recycler view to show same data multiple times.I don't want to copy same data again in room database.
This is what I have done so far:
UserDao.java
#Dao
public interface UserDao {
#Insert(onConflict = OnConflictStrategy.REPLACE)
void Insert(User... users);
#Query("SELECT * FROM Users")
LiveData<List<User>> getRoomUsers();
}
User.java
#Entity(tableName = "Users")
public class User {
#PrimaryKey
private String id;
#ColumnInfo(name = "name")
#SerializedName("name")
#Expose
private String name;
#ColumnInfo(name = "age")
#SerializedName("age")
#Expose
private String age;
public User(String id,String name, String age) {
this.id = id;
this.name = name;
this.age = age;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
}
UserRepository.java
public class UserRepository {
private Context context;
private UserDb userDb;
private LiveData<List<User>> listLiveData;
public UserRepository(Context context) {
this.context = context;
userDb = UserDb.getInstance(context);
listLiveData = userDb.userDao().getRoomUsers();
}
public void getUserList(){
Retrofit retrofit = RetrofitClient.getInstance();
ApiService apiService = retrofit.create(ApiService.class);
Call<List<User>> userList = apiService.getUser();
userList.enqueue(new Callback<List<User>>() {
#Override
public void onResponse(Call<List<User>> call, final Response<List<User>> response) {
Completable.fromAction(new Action() {
#Override
public void run() throws Exception {
if(response.body() != null) {
List<User> list = response.body();
for (int i = 0; i < list.size(); i++) {
String names = list.get(i).getName();
String age = list.get(i).getAge();
String id = UUID.randomUUID().toString();
User user = new User(id,names,age);
userDb.userDao().Insert(user);
}
}
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new CompletableObserver() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onComplete() {
Toast.makeText(context,"Data inserted",Toast.LENGTH_SHORT).show();
}
#Override
public void onError(Throwable e) {
Toast.makeText(context,e.getMessage(),Toast.LENGTH_SHORT).show();
}
});
}
#Override
public void onFailure(Call<List<User>> call, Throwable t) {
Toast.makeText(context,t.getMessage(),Toast.LENGTH_LONG).show();
}
});
}
public LiveData<List<User>> getRoomUsers(){
return listLiveData;
}
}
UserViewModel.java
public class UserViewModel extends AndroidViewModel {
private UserRepository repo;
private LiveData<List<User>> listLiveData;
public UserViewModel(#NonNull Application application) {
super(application);
repo = new UserRepository(application);
listLiveData = repo.getRoomUsers();
}
public LiveData<List<User>> getListLiveData() {
return listLiveData;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
UserRepository userRepository;
RecyclerView recyclerView;
UserViewModel userModel;
List<User> userList;
UserAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
userRepository = new UserRepository(this);
userModel = ViewModelProviders.of(this).get(UserViewModel.class);
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
userList = new ArrayList<>();
adapter = new UserAdapter(userList,this);
recyclerView.setAdapter(adapter);
userModel.getListLiveData().observe(this, new Observer<List<User>>() {
#Override
public void onChanged(List<User> users) {
adapter.setUserList(users);
}
});
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(MainActivity.this,AddUser.class);
startActivity(i);
}
});
userRepository.getUserList();
}
UserAdapter.java
public class UserAdapter extends
RecyclerView.Adapter<UserAdapter.ViewHolder> {
List<User> userList;
Context context;
public UserAdapter(List<User> userList, Context context) {
this.userList = userList;
this.context = context;
}
#NonNull
#Override
public UserAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.user_row_layout,parent,false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull UserAdapter.ViewHolder holder, int position) {
User users = userList.get(position);
holder.row_name.setText(users.getName());
holder.row_age.setText(users.getAge());
}
#Override
public int getItemCount() {
return userList.size();
}
public void setUserList(List<User> userList) {
this.userList = userList;
notifyDataSetChanged();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView row_name,row_age;
public ViewHolder(#NonNull View itemView) {
super(itemView);
row_name = itemView.findViewById(R.id.row_name);
row_age = itemView.findViewById(R.id.row_age);
}
}
}
Someone please let me know how can I achieve desired result. Any help would be appreciated.
THANKS

The answer is quite simple, you do not have a unique primary key. You're generating a key yourself using
String id = UUID.randomUUID().toString();
In your first request, you might have this:
User("mdkasdkasjkdjakjdkasd", "Zun", 22);
and in your second request you get
User("djei3ujf493j9fj49dj9", "Zun", 22);
as such, you'll always have duplicate entries in your database since room considers the user with name 'Zun" to NOT be the same.
In order to solve this, create a unique primary key that's unique to a User class. Do not use a random text generator.

Okay you should do it like this,
check if user is exist in db or not,
#Query("SELECT * FROM user WHERE id = :userId")
public User idUserExists(int userId);
if it does than add update query
#Update
public void updateUser(User user); // keep the model with same user id
else insert the new record
#Insert
public void insertUser(User user); // Model with new user Id

Data fetched from server is copying multiple times in room database

In my app I am using room as a database cache.I am fetching data from server using retrofit library and saving the data inside room database and showing the same data from room in recycler view.
Problem: Whenever activity starts it fetches data from server and saving it in room database due to which same data showing multiple times in recycler view.
What I want: I want to know how can I check if data already present in room should not save multiple time in room and if some new data updated on server it should fetch new data and save it to the room database.
This is what I have done so far:
UserDao.java
#Dao
public interface UserDao {
#Insert(onConflict = OnConflictStrategy.REPLACE)
void Insert(User... users);
#Query("SELECT * FROM Users")
LiveData<List<User>> getRoomUsers();
}
User.java
#Entity(tableName = "Users")
public class User {
#PrimaryKey
private String id;
#ColumnInfo(name = "name")
#SerializedName("name")
#Expose
private String name;
#ColumnInfo(name = "age")
#SerializedName("age")
#Expose
private String age;
public User(String id,String name, String age) {
this.id = id;
this.name = name;
this.age = age;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
}
UserRepository.java
public class UserRepository {
private Context context;
private UserDb userDb;
private LiveData<List<User>> listLiveData;
public UserRepository(Context context) {
this.context = context;
userDb = UserDb.getInstance(context);
listLiveData = userDb.userDao().getRoomUsers();
}
public void getUserList(){
Retrofit retrofit = RetrofitClient.getInstance();
ApiService apiService = retrofit.create(ApiService.class);
Call<List<User>> userList = apiService.getUser();
userList.enqueue(new Callback<List<User>>() {
#Override
public void onResponse(Call<List<User>> call, final Response<List<User>> response) {
Completable.fromAction(new Action() {
#Override
public void run() throws Exception {
if(response.body() != null) {
List<User> list = response.body();
for (int i = 0; i < list.size(); i++) {
String names = list.get(i).getName();
String age = list.get(i).getAge();
String id = UUID.randomUUID().toString();
User user = new User(id,names,age);
userDb.userDao().Insert(user);
}
}
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new CompletableObserver() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onComplete() {
Toast.makeText(context,"Data inserted",Toast.LENGTH_SHORT).show();
}
#Override
public void onError(Throwable e) {
Toast.makeText(context,e.getMessage(),Toast.LENGTH_SHORT).show();
}
});
}
#Override
public void onFailure(Call<List<User>> call, Throwable t) {
Toast.makeText(context,t.getMessage(),Toast.LENGTH_LONG).show();
}
});
}
public LiveData<List<User>> getRoomUsers(){
return listLiveData;
}
}
UserViewModel.java
public class UserViewModel extends AndroidViewModel {
private UserRepository repo;
private LiveData<List<User>> listLiveData;
public UserViewModel(#NonNull Application application) {
super(application);
repo = new UserRepository(application);
listLiveData = repo.getRoomUsers();
}
public LiveData<List<User>> getListLiveData() {
return listLiveData;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
UserRepository userRepository;
RecyclerView recyclerView;
UserViewModel userModel;
List<User> userList;
UserAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
userRepository = new UserRepository(this);
userModel = ViewModelProviders.of(this).get(UserViewModel.class);
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
userList = new ArrayList<>();
adapter = new UserAdapter(userList,this);
recyclerView.setAdapter(adapter);
userModel.getListLiveData().observe(this, new Observer<List<User>>() {
#Override
public void onChanged(List<User> users) {
adapter.setUserList(users);
}
});
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(MainActivity.this,AddUser.class);
startActivity(i);
}
});
userRepository.getUserList();
}
In MainActivity.java userRepository.getUserList() fetches data from server and save it in room database.
Some one please let me know how can I get desired result. Any help would be appreciated.
THANKS

As #a_local_nobody says add this to your Dao.
#Insert(onConflict = OnConflictStrategy.REPLACE)
But this will not fully solve your problem. If you see SQLite doc it says
The ON CONFLICT clause applies to UNIQUE, NOT NULL, CHECK, and PRIMARY KEY constraints. The ON CONFLICT algorithm does not apply to FOREIGN KEY constraints.
Your entity defines a Primary Key but it is tagged with autoGenerate = true. Due to this whenever you create a new User instance and calling insert on your Dao Room is generating a new primary key. This id does not conflict with the "duplicate" User in your db, and hence Room is happy to insert this one without touching the previous "duplicate" version.
The solution is to have the Primary Key from the backend or have a UNIQUE constraint on one field of User entity.

consider looking at this annotation for room :
#Insert(onConflict = OnConflictStrategy.REPLACE)
with this, if you insert anything which already exists, it will simply replace it.
where you are calling :
#Override
public void onChanged(List<User> users) {
adapter.setUserList(users);
}
try clearing the list of the adapter first

anyone looking in the future. The best possible way to do this is to delete the table before inserting new data. e.g.
in your #Dao class define #delete query
#Query("DELETE FROM Users")
void deleteAllUsersData();
and call this query every time before inserting new data into the database. if you want the same primary key then set #Primary key autogenerate to false.

Unable to retrieve firestore database using recyclerView

I am using recyclerView and Adapter to fetch the data in profileActivity
here is my
public class studentDetailsRecyclerActivity extends AppCompatActivity {
//recyclerview to set the details for UI in the student profile activity
private RecyclerView mRecyclerView;
private storeDetailsAdapter mStoreDetailsAdapter;
private List<storeStudentDetails> studentDetailsList;
private FirebaseFirestore dbReference;
private ProgressBar mProgressBar;
private String TAG = studentDetailsRecyclerActivity.class.getSimpleName();
#Override
protected void onCreate(Bundle savedInstanceState) {
dbReference = FirebaseFirestore.getInstance();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_details);
mProgressBar = findViewById(R.id.progressbar);
mRecyclerView = (RecyclerView)findViewById(R.id.recyclerView_products);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
studentDetailsList = new ArrayList<>();
mStoreDetailsAdapter = new storeDetailsAdapter(this,studentDetailsList);
mRecyclerView.setAdapter(mStoreDetailsAdapter);
//to get the "details" this is our collection from firestore so we must fetch them
//by calling the addOnSuccessListener
dbReference.collection("details").get()
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
#Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) { //we must have to hide the progress bar when the data gets loaded
//here queryDocumentsSnapshot will hold all the "details" which is your collection in firestore
if(!queryDocumentSnapshots.isEmpty()){
//we must have to create empty list so that to store all
//details from DocumentsSnapshots
List<DocumentSnapshot> list = queryDocumentSnapshots.getDocuments();
//enhanced for loop because we have to give every index documentSnapShot
for(DocumentSnapshot d: list){
storeStudentDetails sd = d.toObject(storeStudentDetails.class);
studentDetailsList.add(sd);
Log.d(TAG, "onSuccess: " + sd.toString());
}
//to refresh and sync we must have to use notifyDataSetChanged
mStoreDetailsAdapter.notifyDataSetChanged();
}
}
}) .addOnFailureListener(new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
Toast.makeText(getApplicationContext(), "Error getting data!!!", Toast.LENGTH_LONG).show();
}
});
}
}
and here is my storeDetailsAdapter
import java.util.List;
public class storeDetailsAdapter extends RecyclerView.Adapter<storeDetailsAdapter.StudentViewHolder>{
private Context context;
private List<storeStudentDetails> studentDetailsList;
public storeDetailsAdapter(Context context, List<storeStudentDetails> studentDetailsList) {
this.context = context;
this.studentDetailsList = studentDetailsList;
}
#NonNull
#Override
public StudentViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
return new StudentViewHolder(
LayoutInflater.from(context).inflate(R.layout.profile_activity, parent, false)
);
}
#Override
public void onBindViewHolder(#NonNull StudentViewHolder holder, int position) {
storeStudentDetails mStoreDetails = studentDetailsList.get(position);
holder.studName.setText(mStoreDetails.getStudentName());
holder.rollNum.setText(mStoreDetails.getRollNo());
holder.bookName.setText( mStoreDetails.getBook());
holder.fine.setText("Fine:" + mStoreDetails.getFine());
holder.dept.setText(mStoreDetails.getDept());
}
#Override
public int getItemCount() {
return studentDetailsList.size();
}
class StudentViewHolder extends RecyclerView.ViewHolder {
TextView studName,rollNum,bookName,dept,fine;
public StudentViewHolder(View itemView) {
super(itemView);
studName=itemView.findViewById(R.id.studentName_prof);
rollNum = itemView.findViewById(R.id.rollNumber_prof);
bookName = itemView.findViewById(R.id.bookName_prof);
fine = itemView.findViewById(R.id.fineAmt_prof);
dept = itemView.findViewById(R.id.department_prof);
}
}
}
and here is my StoreStudentDetails class:
public class storeStudentDetails implements Serializable {
private String studentName;
private String rollNo;
private String book;
private Double fine;
private String dept;
#Exclude private String id;
public storeStudentDetails() {
}
public storeStudentDetails(String studentName, String rollNo,String book, double fine ,String dept) {
this.studentName = studentName;
this.rollNo = rollNo;
this.book = book;
this.fine = fine;
this.dept = dept;
}
public void setId(String id) {
this.id = id;
}
public String getStudentName() {
return studentName;
}
public String getRollNo() {
return rollNo;
}
public String getBook() {
return book;
}
public Double getFine() {
return fine;
}
public String getDept() {
return dept;
}
public String getId() {
return id;
}
}

To solve this, please move the following lines of code:
mStoreDetailsAdapter = new storeDetailsAdapter(this,studentDetailsList);
mRecyclerView.setAdapter(mStoreDetailsAdapter);
Right before the following line of code:
mStoreDetailsAdapter.notifyDataSetChanged();
And this is because onSuccess() method has an asynchronous behavior and by the time you are setting the adapter outside the callback your list is empty.
As you can see, the easiest solution for this problem is to move those lines of code inside the callback. but if you want to use the value of your studentDetailsList outside the onSuccess() method, I recommend you see the last part of my anwser from this post in which I have explained how it can be done using a custom callback. You can also take a look at this video for a better understanding.

unable to retrieve data from one app to another app from firebase single Database

I have 2 applications(different package names) which use one Firebase database. One app has to write access to the database and another have read access to the database.in my second application, i use recyclerview to retrieve data which is stored by 1st App.
for this I use below code:
FirebaseOptions options = new FirebaseOptions.Builder()
.setApplicationId("1:567....259c8f58311") // Required for Analytics.
.setApiKey("AIzaSyA9BRxl......hE03y5qD-c") // Required for Auth.
.setDatabaseUrl("https://mycity-3a561.firebaseio.com/") // Required for RTDB.
.build();
FirebaseApp.initializeApp(this /* Context */, options, "MyCity");
// Retrieve my other app.
FirebaseApp app = FirebaseApp.getInstance("MyCity");
// Get the database for the other app.
FirebaseDatabase secondaryDatabase = FirebaseDatabase.getInstance(app);
DatabaseReference data = secondaryDatabase.getInstance().getReference();
data.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
for (DataSnapshot ds : snapshot.getChildren()) {
for (DataSnapshot dSnapshot : ds.getChildren()) {
WaterClass waterClass = dSnapshot.getValue(WaterClass.class);
Log.d("Show", waterClass.getName() == null ? "" : waterClass.getName());
list.add(waterClass);
}
adapter = new WaterAdapter(ShowWaterDetails.this, list);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
progressDialog.dismiss();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
progressDialog.dismiss();
}
});
}
Adapter class
private class WaterAdapter extends RecyclerView.Adapter<WaterAdapter.ViewHolder> {
ShowWaterDetails showDetail;
List<WaterClass> listData;
public WaterAdapter(ShowWaterDetails showWaterDetails, List<WaterClass> list) {
this.showDetail = showWaterDetails;
this.listData = list;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.show_items, parent, false);
WaterAdapter.ViewHolder viewHolder = new WaterAdapter.ViewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(WaterAdapter.ViewHolder holder, int position) {
WaterClass AllDetails = listData.get(position);
holder.NameTextView.setText(AllDetails.getName());
holder.DetailTextView.setText(AllDetails.getDetail());
holder.DateTextView.setText(AllDetails.getDate());
holder.LocationTextView.setText(AllDetails.getLocation());
holder.TypeTextView.setText(AllDetails.getType());
Picasso.with(showDetail).load(AllDetails.getImgurl()).resize(120, 60).into(holder.ImageTextView);
}
#Override
public int getItemCount() {
return listData.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
public TextView NameTextView;
public TextView DetailTextView;
public TextView DateTextView;
public TextView LocationTextView;
public TextView TypeTextView;
public ImageView ImageTextView;
public ViewHolder(View itemView) {
super(itemView);
NameTextView = itemView.findViewById(R.id.ShowNameTextView);
DetailTextView = itemView.findViewById(R.id.ShowDetailTextView);
DateTextView = itemView.findViewById(R.id.ShowDateTextView);
LocationTextView = itemView.findViewById(R.id.ShowLocationTextView);
TypeTextView = itemView.findViewById(R.id.ShowTypeTextView);
ImageTextView = itemView.findViewById(R.id.ShowImageView);
}
}
}
}
POJO Class
class WaterClass {
private String id;
private String email;
private String name;
private String type;
private String detail;
private String location;
private String date;
private String imgurl;
public WaterClass(){
}
public WaterClass(String id, String currentUserString, String imageUrl, String nameString, String typeString, String detailString, String locationString, String dateString) {
this.id = id;
this.email = currentUserString;
this.name =nameString;
this.type = typeString;
this.detail = detailString;
this.location = locationString;
this.date = dateString;
this.imgurl = imageUrl;
}
public String getImgurl() {
return imgurl;
}
public void setImgurl(String imgurl) {
this.imgurl = imgurl;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getDetail() {
return detail;
}
public void setDetail(String detail) {
this.detail = detail;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
}
:
there is no error but my recycler not showing anything

go to onStart() and start listening
#Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
and in your onStop
#Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
The FirebaseRecyclerAdapter uses a snapshot listener to monitor changes to the Firestore query. To begin listening for data, call the startListening() method. You may want to call this in your onStart() method. Make sure you have finished any authentication necessary to read the data before calling startListening() or your query will fail.
Be sure that the names of constant in the POJO match exatly the names
of your database structure in your firebase console !!
ps: do not post your api-keys or app-ids in your questions, keep them secret, and consider using firebaserecycleradapter if you are using firebase-database , it will be more easy to setup and to show values.
Your POJO is ok !

Found Solution!!
just change this part of a code
FirebaseApp.initializeApp(this /* Context */, options, "MyCity");
// Retrieve my other app.
FirebaseApp app = FirebaseApp.getInstance("MyCity");
TO
FirebaseApp.initializeApp(this);
// Retrieve my other app.
FirebaseApp app = FirebaseApp.getInstance("[DEFAULT]");