My query is that I want to save some data in Firebase Realtime Database such that I will be able to call the data. Keeping in mind that users should be able to call the data even if they reinstall the app and each user will have a specific child.
I am trying to make an app where the user will enter or save data to firebase and display it on the App, however, the issue is that I am not having an Idea on how to retrieve the data from firebase.
The data which I am going to retrieve is the ItemName which I have saved inside
child(uid).child(ItemName);
each user will save their data with different uid inside different ItemName.
The thing is that how will I retrieve the ItemName for each user since the ItemName will be different so I will not have any data of the ItemName for a particular user. If I save the ItemName in SharedPreferences I will be able to retrieve it, however, if the user, formate their phone or uninstall and reinstall the app then SharedPreference data will be removed, SO HOW WILL I RETRIVE THE ITEMNAME data from Firebase for a particular user to display it.
MY CODE example:
String email= mAuth.getCurrentUser().getUid();
dbFirestore= FirebaseFirestore.getInstance();
userReference= FirebaseDatabase.getInstance().getReference().child("Users").child(itemName);
Is there any method or function which retrieve the data without specifying the Child pathname like default path if we redirect the path towards there like
databaseReference = FirebaseDatabase.getInstance().getReference().child(uid).child("");
something like that. or is there any other way to do it.
To those values, without knowing the name of the intermediate node, please use the following lines of code:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference uidRef = rootRef.child(uid);
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String friedChicken = ds.getKey();
String foodType = ds.child("food_TYPE").getValue(String.class);
Log.d("TAG", friedChicken + "/" + foodType);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d("TAG", databaseError.getMessage()); //Don't ignore errors!
}
};
uidRef.addListenerForSingleValueEvent(valueEventListener);
The output in the logcat will be:
Fried Chicken / Non-Veg
In the same way I got the value of food_TYPE, you can also get the others.
You can do the following
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child(uid).child("Fried Chicken");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
String foodType = dataSnapshot.child("food_TYPE").getValue().toString();
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
Related
How can we access all UID users name and the UID users child value in Firebase database?
I have uploaded the pic of my database
I also use RecyclerView you tell me about Firebase query I want to retrieve data with FirestoreRecyclerOptions query :
I want to access
name of users and the amount value as shown in fig
like this
name:600
To get all user names, of all User objects that exist under "Users" node, please use the following lines of code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference usersRef = rootRef.child("Users");
productsRef.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
#Override
public void onComplete(#NonNull Task<DataSnapshot> task) {
if (task.isSuccessful()) {
for (DataSnapshot ds : task.getResult().getChildren()) {
String name = ds.child("name").getValue(String.class);
Log.d(TAG, name);
}
} else {
Log.d(TAG, task.getException().getMessage()); //Don't ignore potential errors!
}
}
});
Because there are several objects within the "Users" node, first you need to get a reference to that node, attach a listener and then loop through the results. The result in the logcat will be:
jm
...
If you want to use the Firebase-UI library, then simply pass the "usersRef" to the FirestoreRecyclerOptions's setQuery() method, as explained in my answer from the following post:
How to display data from Firestore in a RecyclerView with Android?
What is the proper way to read data from Firebase Realtime Database? I have created a database "Mybill"s with child bills. In child Bills, I am saving UserId from FirebaseAuth so it should be easy to find bills for a specific user and in userID child, I have a child that I have created using the .push() method and in that, I have data about the bill.
It looks like this:
How should I change my Java code so I can get all the bills saved for a specific user (the user that is currently logged in)
this is my code for now :
final FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("bills");
Query checkUser = ref.orderByChild("UserId").equalTo(Autentication.GetUser());
// Attach a listener to read the data at our posts reference
checkUser.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String email = dataSnapshot.child("email").getValue(String.class);
String market = dataSnapshot.child("market").getValue(String.class);
String price = dataSnapshot.child("price").getValue(String.class);
String date = dataSnapshot.child("date").getValue(String.class);
}
#Override
public void onCancelled(DatabaseError databaseError) {
System.out.println("The read failed: " + databaseError.getCode());
}
});
How should I change my Java code so I can get all the bills saved for a specific user (the user that is currently logged in)
To do that, please use the following lines of code:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference uidRef = rootRef.child("bills").child(uid);
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String email = ds .child("email").getValue(String.class);
String market = ds .child("market").getValue(String.class);
String price = ds .child("price").getValue(String.class);
Log.d("TAG", email + "/" + market + "/" + price);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d("TAG", databaseError.getMessage()); //Don't ignore potential errors!
}
};
uidRef.addListenerForSingleValueEvent(valueEventListener);
The "date" cannot be read as a String, as it's an object. So the most appropriate way would be to read it as a Map<String, Object>. In this way, you are getting only the bills that correspond to a specific user (logged-in user).
I'm trying to get the name and phone for the current user from the Non Member node.But for some reason I'm always getting the value for name and phone to be NULL. I debugged and traced it back to find that the Value of the DataSnapshot for the current user is NULL.
Code :
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("NonMember");
final FirebaseUser Key = firebaseAuth.getCurrentUser();
final String userKey = Key.getUid();
if(firebaseAuth.getCurrentUser() == null){
finish();
startActivity(new Intent(getApplicationContext(), MEMBERMAINActivity.class));
}
myRef.child(userKey).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot){
for (DataSnapshot ds: dataSnapshot.getChildren()){
String name = dataSnapshot.child("name").getValue().toString();
Log.d("TAG", "Name"+ name);
// profile_name.setText(name);
}}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Toast.makeText(MyProfile.this, databaseError.getCode(), Toast.LENGTH_SHORT).show();
}
});
The keys you have in the database under "NonMember" are not Firebase Auth user IDs. They look like Realtime Database push IDs, which means you've likely added the user data with something like myRef.push().setValue(...). However, your code is attempting to use a user ID to locate user data. The ID you're getting from Firebase Auth is just not matching the data in the database. If your query doesn't match any data, then it will get a null value in the snapshot.
If you want to store per-user data, don't use a Realtime Database push operation - use the ID of the user, with something like myRef.child(userKey).setValue(...).
for (DataSnapshot ds: dataSnapshot.getChildren()){
String name = ds.child("name").getValue().toString();
Log.d("TAG", "Name"+ name);
// profile_name.setText(name);
}
try this
I'm developing a travel Android app and the idea is that a user can authenticate and create a personal account through Firebase Authentication. One of the functionalities says that every user can post reviews. Now, what I want is to retrieve all the reviews from the Firebase Realtime Database (not just the current user reviews, all of them). How could I achieve this?
To get all the reviews that correspond to all users, you have to iterate twice, like in the following lines of code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference reviewsRef = rootRef.child("reviews");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot uidSnapshot : dataSnapshot.getChildren()) {
for(DataSnapshot reviewSnapshot : uidSnapshot.getChildren()) {
String comment = reviewSnapshot.child("comment").getValue(String.class);
Log.d("TAG", comment);
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d("TAG", databaseError.getMessage()); //Don't ignore errors!
}
};
reviewsRef.addListenerForSingleValueEvent(valueEventListener);
The output in the logcat will be:
Really nice place
The ideal place for holiday. No matter if it
Hi
If you are using a POJO class for your review object, then please use:
Review review = reviewSnapshot.getValue(Review.class);
Log.d("TAG", review.getComment());
For example, there are 2 main nodes in my database (there can be more). The parent node is the user's authentication id and inside it
there is some detail as you can see.
I am trying to do that if any user login all other user's data populated on his activity
but I really don't know how to start because every user has its own authentication id and there are sub-nodes also like map location and image
How can I fetch every user's detail to the activity?
What you can do is that get the data from the fbuserinfo node using an event listener like this and iterate through the data. Here User.class is the class for the User model that you have created
DatabaseReference userDataReference = FirebaseDatabase.getInstance().getReference()
.child("fbuserinfo");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot ds : dataSnapshot.getChildren()) {
User user = ds.getValue(User.class);
Log.d("User", user);
}
}
}
#Override
public void onCancelled (DatabaseError databaseError){
Log.d(TAG, "Error fetching user data - " + databaseError.getMessage());
}
}
userDataReference.addListenerForSingleValueEvent(eventListener);
And then if you want to display the data, you can do it in the for loop and have an if condition to check if the user is not equal to the current one
Using the following example you'll be able to log the name of all users from your database.
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference fbRef = rootRef.child("Users").child("fbusersinfo");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String name = ds.child("name").getValue(String.class);
Log.d("TAG", name);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
fbRef.addListenerForSingleValueEvent(eventListener);
The output will be:
Ahmend Abbas
mahanoor 4
If you need also the other properties, you can get them in the same manner.