I am working on an application where anyone can list their products. I am storing data in Firebase Firestore in nested collection Now I want to retrieve that data and show that on my home screen. Now the data is showing but the problem is that it is showing only when I am login in with that same number through that I list that data into Firebase but when I try to log in with another number the data doesn't show. I want that to show to everyone who logged in to the app. Basically My app is just like OLX where anyone can list anything which shows to everyone.
MY CODE TO RETRIEVE THE DATA
//CODE TO GET CURRENT ID OR USER
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
//CODE TO GET THE DATA FROM FIREBASE
DocumentReference uidRef = firebaseFirestore.collection("listing_details").document(uid);
CollectionReference roomDetailsRef = uidRef.collection("room_details");
String doc_id = roomDetailsRef.document().getId();
roomDetailsRef.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
if (document != null) {
RoomsDetails obj = document.toObject(RoomsDetails.class);
roomsDetails.add(obj);
}
}
roomsAdapter.notifyDataSetChanged();
} else {
Log.d(TAG, task.getException().getMessage()); //Never ignore potential errors!
}
}
});
You have .document(uid) in your path where UID is User ID of user currently logged in. When you use another phone number, that's a different user.
If you want to fetch room_details documents from all listing_details documents then you can use Collection Group queries like this:
db.collectionGroup("room_details").get()
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
#Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
// ... iterate over all docs and render
}
});
What I want is: to check if the user input value is available in the database. I have an EditText in my app, the user enters a phone number. When he clicks the button, the button requests to see in the database to see if the user input matches any record of a phone number in the database.
I haven't done anything um lost, but I have a screenshot of my database structure.
To check for example, if "+263782876566" already exists in the database, please use the following lines of code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference officeRef = rootRef.child("Users").child("Office");
Query queryByPhone = officeRef.orderByChild("phone").equalTo("+263782876566");
officeRef.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
#Override
public void onComplete(#NonNull Task<DataSnapshot> task) {
if (task.isSuccessful()) {
for (DataSnapshot ds : task.getResult().getChildren()) {
String type = ds.child("type").getValue(String.class);
Log.d(TAG, type);
}
} else {
Log.d(TAG, task.getException().getMessage()); //Don't ignore potential errors!
}
}
});
So we are using a reference that points to Users -> Office and then we create a Query object to actually check within all children if the "phone" property holds a specific value. If we find some results, we simply log the type. In your particular example, the result in the logcat will be:
Office member
I use the firebase realtime database to store user information.
Here is a picture of the database:
screenshot of the database
For example, how can I get the value "nombre_dons" according to the connected user to display it in the application ? I use android studio in java.
Thank you in advance for your help
Those parent strings of the user data in Users node in your database look like the uids. If they indeed are, then all you need to do is to retrieve data from those uids for the particular user.
What I am saying looks something like this in code:
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Users");
FirebaseAuth mAuth = FirebaseAuth.getInstance();
ref.child(mAuth.getUid()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String data = dataSnapshot.child("nombre_dons").getValue(String.class);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.d(TAG, "onCancelled", databaseError.toException());
}
});
One flaw I can see in your database image is that nombre_dons child in second user in your Users node has capital N, which would be a problem, because Firebase is case sensitive. I'd advise you to keep it same as others.
Assuming the keys inside 'Users' in your database are Firebase Authentication UserId(s), you can follow these steps-
1. Get UID of the current user.
2. Fetch data for the same.
Using Javascript -
var uid = firebase.auth().currentUser.uid;
firebase.database().ref('/Users/' + uid).once('value').then(function(snapshot){
var nombre_dons = snapshot.val().nombre_dons;
});
I have a collection of users and I want to query all users from the database and display them in a RecyclerView except one, mine. This is my db schema:
users [collection]
- uid [document]
- uid: "fR5bih7SysccRu2Gu9990TeSSyg2"
- username: "John"
- age: 22
- //other users
How to query the database like so:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
Query q = db.collection("users").whereNotEqualTo("uid", uid);
So I need this query object to be passed to a FirestoreRecyclerOptions object in order to display all the other users in RecyclerView.
Is this even possible? If not, how can I solve this? Thanks!
Edit:
options = new FirestoreRecyclerOptions.Builder<UserModel>()
.setQuery(query, new SnapshotParser<UserModel>() {
#NonNull
#Override
public UserModel parseSnapshot(#NonNull DocumentSnapshot snapshot) {
UserModel userModel = documentSnapshot.toObject(UserModel.class);
if (!userModel.getUid().equals(uid)) {
return userModel;
} else {
return new UserModel();
}
}
}).build();
After days and days of struggling with this issue, I finally found the answer. I could not solve this without the help of #Raj. Thank you so much #Raj for the patience and guidance.
First off all, according to the answer provided by #Frank van Puffelen in his answer from this post, I stopped searching for a solution that can help me pass two queries to a single adapter.
In this question, all that I wanted to achieve was to query the database to get all the users except one, me. So because we cannot combine two queries into a single instance, I found that we can combine the result of both queries. So I have created two queries:
FirebaseFirestore db = FirebaseFirestore.getInstance();
Query firstQuery = db.collection("users").whereLessThan("uid", uid);
Query secondQuery = db.collection("users").whereGreaterThan("uid", uid);
I'm having a UserModel (POJO) class for my user object. I found not one, but two ways to solve the problem. The first one would be to query the database to get all user objects that correspond to the first criteria and add them to a list. After that, query the database again and get the other user objects that correspond to the second criteria and add them to the same list. Now I have a list that contains all the users that I need but one, the one with that particular id from the queries. This is the code for future visitors:
firstQuery.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
List<UserModel> list = new ArrayList<>();
if (task.isSuccessful()) {
for (DocumentSnapshot document : task.getResult()) {
UserModel userModel = document.toObject(UserModel.class);
list.add(userModel);
}
secondQuery.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (DocumentSnapshot document : task.getResult()) {
UserModel userModel = document.toObject(UserModel.class);
list.add(userModel);
}
//Use the list of users
}
}
});
}
}
});
The second approach would be much shorter because I use Tasks.whenAllSuccess() like this:
Task firstTask = firstQuery.get();
Task secondTask = secondQuery.get();
Task combinedTask = Tasks.whenAllSuccess(firstTask, secondTask).addOnSuccessListener(new OnSuccessListener<List<Object>>() {
#Override
public void onSuccess(List<Object> list) {
//This is the list that I wanted
}
});
According to the official firestore documentation:-
Cloud Firestore does not support the following type of query:
Queries with a != clause. In this case, you should split the query
into a greater-than query and a less-than query. For example, although
the query clause where("age", "!=", "30") is not supported, you can
get the same result set by combining two queries, one with the clause
where("age", "<", "30") and one with the clause where("age", ">", 30).
If you are using FirestoreRecyclerAdapter then FirestoreRecyclerOptions will directly accepts the query using setQuery() method and hence not allows you to perform client side filtering.
If you try to apply filters in onBindViewHolder() while setting the data that might results in empty items in the recycler view. In order to resolve that refer Method 2.
So, the possible solution to your problem would be to create an integer field in your users collection under every document. Eg:-
users [collection]
- uid [document]
- uid: "fR5bih7SysccRu2Gu9990TeSSyg2"
- username: "John"
- age: 22
- check: 100
In this I have created a 'check' variable whose value is 100. So, put value of 'check' in all other documents as less than 100.
Now, you can easily make a query that finds documents with check<100 as:-
Query q = db.collection("users").whereLessThan("check", 100);
This will retrieve all your documents except the one you don't want. And while setting the data you can set other parameters skipping the check variable.
Method 2 (Client Side Filtering)
We can apply a check in onBindViewHolder() method that if the retrieved uid matches with current user uid then set the height of Recycler view as 0dp. As:-
ViewUserAdapter.java
public class ViewUserAdapter extends FirestoreRecyclerAdapter<User, ViewUserAdapter.ViewUserHolder>
{
String uid;
FirebaseAuth auth;
public ViewUserAdapter(#NonNull FirestoreRecyclerOptions<User> options)
{
super(options);
auth = FirebaseAuth.getInstance();
uid = auth.getCurrentUser().getUid();
}
#Override
protected void onBindViewHolder(#NonNull ViewUserHolder holder, int position, #NonNull User model)
{
DocumentSnapshot snapshot = getSnapshots().getSnapshot(position);
String id = snapshot.getId();
if(uid.equals(id))
{
RecyclerView.LayoutParams param = (RecyclerView.LayoutParams)holder.itemView.getLayoutParams();
param.height = 0;
param.width = LinearLayout.LayoutParams.MATCH_PARENT;
holder.itemView.setVisibility(View.VISIBLE);
}
else
{
holder.tvName.setText(model.name);
holder.tvEmail.setText(model.email);
holder.tvAge.setText(String.valueOf(model.age));
}
}
}
2021 Update: This Is Supported
Howdy devs. It looks like this is now supported with the where operator used like this: citiesRef.where("capital", "!=", false);
Firestore doesn't support not equal to operation. So you need to filter the data at the client side. Since in you case you only have one extra item you can filter it out.
For that you may need to build your own recycler implementation where when adding data to recycler adapter data layer, you restrict the data when ever it matches your != condition.
I haven't explored recycler implementation firebase provided so I cannot say it supports data manipulation to adapter data or not.
Here is a good resource to start implementing recycler view : https://www.androidhive.info/2016/01/android-working-with-recycler-view/
The simplest solution would be to use a PagedListAdapter and create a custom DataSource for the Firestore queries. In the DataSource the Query can be transformed into an Array or ArrayList in which you can easily remove your item before adding the data to the method callback.onResult(...).
I used a similar solution to process data after a Firestore query in order to filter and sort by a time attribute, and then re-sort by a quality score attribute in the client before passing the data back in to callback.onResult(...).
Documentation
Google: Build your own data sources
Codepath: Paging Library Guide
Data Source Sample
class ContentFeedDataSource() : ItemKeyedDataSource<Date, Content>() {
override fun loadBefore(params: LoadParams<Date>, callback: LoadCallback<Content>) {}
override fun getKey(item: Content) = item.timestamp
override fun loadInitial(params: LoadInitialParams<Date>, callback: LoadInitialCallback<Content>) {
FirestoreCollections.contentCollection
.collection(FirestoreCollections.ALL_COLLECTION)
.orderBy(Constants.TIMESTAMP, Query.Direction.DESCENDING)
.whereGreaterThanOrEqualTo(Constants.TIMESTAMP, DateAndTime.getTimeframe(WEEK))
.limit(params.requestedLoadSize.toLong())
.get().addOnCompleteListener {
val items = arrayListOf<Content?>()
for (document in it.result.documents) {
val content = document.toObject(Content::class.java)
items.add(content)
}
callback.onResult(items.sortedByDescending { it?.qualityScore })
}
}
override fun loadAfter(params: LoadParams<Date>, callback: LoadCallback<Content>) {
FirestoreCollections.contentCollection
.collection(FirestoreCollections.ALL_COLLECTION)
.orderBy(Constants.TIMESTAMP, Query.Direction.DESCENDING)
.startAt(params.key)
.whereGreaterThanOrEqualTo(Constants.TIMESTAMP, DateAndTime.getTimeframe(WEEK))
.limit(params.requestedLoadSize.toLong())
.get().addOnCompleteListener {
val items = arrayListOf<Content?>()
for (document in it.result.documents) {
val content = document.toObject(Content::class.java)
items.add(content)
}
val sortedByQualityScore = ArrayList(items.sortedByDescending { it?.qualityScore })
callback.onResult(sortedByQualityScore)
sortedByQualityScore.clear()
}
}
}
Simpler and earlier client-side filtering (when you add items to your list):
Get the current user's ID by using Firestore's standard method.
Get the name of the doc for all the users in your user collection.
Before adding the user to
your RecyclerView list, check that the user it is about to add to your list is not the current user.
When done is this way, you can use the "not equals" method on the client side and not get into any Firestore issues. Another benefit is that you don't have to mess with your adapter or hide the view from a list-item you didn't want in the recycler.
public void getUsers(final ArrayList<Users> usersArrayList, final Adapter adapter) {
CollectionReference usersCollectionRef = db.collection("users");
Query query = usersCollectionRef
.whereEqualTo("is_onboarded", true);
query.get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
final String otherUserID = document.getId();
FirebaseUser user = mAuth.getCurrentUser();
String currentUserID = user.getUid();
if (!otherUserID.equals(currentUserId)) {
usersArrayList.add(new User(otherUserID));
adapter.notifyDataSetChanged(); //Ensures users are visible immediately
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});
}
}
} else {
Log.d(TAG, "Error getting documents: ", task.getException());
}
}
});
}
You don't have to do all this
Just do normal query and hide the layout by setting getLayoutParams().height and width to 0 respectively. See example below.
if(firebaseUserId.equalIgnoreCase("your_holder_firebase_user_id"){
holder.mainLayout.setVisibility(View.INVISIBLE);
holder.mainLayout.getLayoutParams().height = 0;
holder.mainLayout.getLayoutParams().width = 0;
}else {
//show your list as normal
}
//This will hide any document snapshot u don't need, it will be there but hidden
here's my solution with flutter for usernames
Future<bool> checkIfUsernameExistsExcludingCurrentUid(
// TODO NOT DONE
String username,
String uid) async {
print("searching db for: $username EXCLUDING SELF");
bool exists = true;
QuerySnapshot result = await _firestore
.collection(USERS_COLLECTION)
.where(
"username",
isEqualTo: username,
)
.getDocuments();
List _documents = result.documents;
_documents.forEach((element) {
if (element['uid'] == uid) {
exists = false;
} else {
return true;
}
});
return exists;
}
When the user checks his friends list in my app, I want the app to go through each user in the list and retrieve his up to date information from the Cloud Firestore.
This is my current code:
final CollectionReference usersRef= FirebaseFirestore.getInstance().collection("users");
usersRef.document(loggedEmail).collection("friends_list").get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
#Override
public void onSuccess(QuerySnapshot documentSnapshots) {
if (!documentSnapshots.isEmpty()){
for (DocumentSnapshot friendDocument: documentSnapshots) {
usersRef.document(friendDocument.getString("email")).get().addOnSuccessListener
(new OnSuccessListener<DocumentSnapshot>() {
#Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
User friend=documentSnapshot.toObject(User.class);
friendsList_UserList.add(friend);
}
});
}
///...
}
else
noFriendsFound();
}
And this is an illustration of my wanted process:
As you can see, I can get the information of each user in this way, but I can't find a way to listen to this process, and proceed when I have the information about all the friends in the user's list.
Is the a way which I'll be able to get all of the friends information at once?
Firestore does not directly support joins like you're asking for.
You could construct a chained listener using the getDocumentChanges in the QuerySnapshot to keep track of which friends you should listen to.
Imagine if you kept a map of friend listener registrations like this
Map<String, ListenerRegistration> friendListeners = new HashMap<>();
Then you could register something like this:
usersRef.document(loggedEmail).collection("friends_list")
.addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(QuerySnapshot snapshot, FirebaseFirestoreException error) {
for (DocumentChange change : snapshot.getDocumentChanges()) {
DocumentSnapshot friend = change.getDocument();
String friendId = friend.getId();
ListenerRegistration registration;
switch (change.getType()) {
case ADDED:
case MODIFIED:
if (!friendListeners.containsKey(friendId)) {
registration = usersRef.document(friendId).addSnapshotListener(null);
friendListeners.put(friendId, registration);
}
break;
case REMOVED:
registration = friendListeners.get(friendId);
if (registration != null) {
registration.remove();
friendListeners.remove(friendId);
}
break;
}
}
}
});
Note, however that this may not actually be a good idea. You may be better off pushing enough information down into the friends_list documents that you only need to load the actual friend user document once you're actually drilling down into that friend's details.