I have integrated Google sign-in in my app and i am pushing some data in to fire base including user U-id.I had researched a lot and didn't get anything the problem i am facing that i want to fetch Particular data for eg If User A sign-in and push 5 data and Then User B sign-in and push 3 data.I want a query like if User A sing-in Again it will get his 5 data only and not the data which is pushed by User B.Thanks in Advance :)
By using this it fetch all the data from firebase:
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot data : dataSnapshot.getChildren()) {
FirebaseModel firebasemodel =
data.getValue(FirebaseModel.class);
firebasemodels.add(firebasemodel);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
I have tried all that .child .orderby and .equalTo but did'nt work
My Structure is Like:
My FireBase Structure
You also need a reference to the data, which isn't included in your code block. So something along the lines of (this should be before this):
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("notepad-secure/notepad");
Firstly add a user_id key in your child data, it will look like below :
id:"",
note:"",
title:"",
user:""
user_id:"{id from which user have you uploaded data}"
And than you can call below function with specific user data like
below Note : "user_id" = id from which user have you uploaded data
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference.child("notepad").orderByChild("id").equalTo("user_id");
query.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
// dataSnapshot is the "notepad" node with all children with id
for (DataSnapshot notepad: dataSnapshot.getChildren()) {
// do something with the individual "notepad_data"
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
To Fetch Particular values from the firebase,try this code
FirebaseDatabase database;
database.getReference().child("notepad-secure").orderByChild("id").equalTo(user).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.getValue() != null) {
for (DataSnapshot childSnapshot : dataSnapshot.getChildren()) {
User userdet =childSnapshot.getValue(yourclass.class);
String note=userdet.note;
//Here you will get the string values what you want to fetch
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
First U have to differentiate.U have to implement Firebase Authentication the u can get Firebase UID of every USER.
String userId = FirebaseAuth.getInstance().getCurrentUser().getUid();
Then store seperatly in new node.
i.e Take Firebase Database Instance and
databaserefernace.child("Data").Child("userID);
When your add a user data to Firebase database, you can add it using the specific uid provided by the FirebaseAuth object like this:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
Assuming you that your database strucure look like this: Firebase root -> notepad-secure -> notepad, to retrieve data, you can use this code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference notepadRef = rootRef.child("notepad-secure").child("notepad").child(uid);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String id = dataSnapshot.child("id").getValue(String.class);
String note = dataSnapshot.child("note").getValue(String.class);
String title = dataSnapshot.child("title").getValue(String.class);
String user = dataSnapshot.child("user").getValue(String.class);
Log.d("TAG", id + " / " + note + " / " + title + " / " + user);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
notepadRef.addListenerForSingleValueEvent(eventListener);
Related
I have developed an admin side application from where I will be adding the email id, pin, city and country data to the firebase realtime database. Then I will be providing the email and pin to the customer. So my simple target is that when the customer logins, the data of city and country should be displayed on his application. To do this I have to search the database for that particular customer's node which can be done through the email id which he puts during login.
I tried my best but everytime null is returned. Please have a look at my code and help me out.
void searchQuery(String email){
DatabaseReference mFirebaseDatabaseReference = FirebaseDatabase.getInstance().getReference();
Query query = mFirebaseDatabaseReference.child("arvi-admin").orderByChild("mailId").equalTo(email);
query.addValueEventListener(valueEventListener);
}
ValueEventListener valueEventListener = new ValueEventListener()
{
#Override
public void onDataChange(DataSnapshot dataSnapshot)
{
try {
DataModel obj = dataSnapshot.getValue(DataModel.class);
logData(""+obj.getCity()); //the values are null
}catch (Exception e){
Log.d("##","Error");
e.printStackTrace();
}
}
#Override
public void onCancelled(DatabaseError databaseError){
}
};
Firebase Database Image
To solve this, please change the following line of code:
Query query = mFirebaseDatabaseReference.child("arvi-admin").orderByChild("mailId").equalTo(email);
to
Query query = mFirebaseDatabaseReference.orderByChild("mailId").equalTo(email);
As you can see, I have removed the call to .child("arvi-admin") because the root is not a child and should not be added in your reference.
Edit:
Query query = mFirebaseDatabaseReference.orderByChild("mailId").equalTo(email);
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
DataModel obj = ds.getValue(DataModel.class);
Log.d(TAG, obj.getCity());
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
}
};
query.addListenerForSingleValueEvent(valueEventListener);
I am currently working on a chat app using Firebase and am looking for some help or clarification. So my Database is structured below. Under the ChatID node are random push IDs that each contain some information which get made everytime a message is sent. Is it possible to get the last push ID automatically so I can obtain only the information stored in that push key? I have seen using orderbykey but not sure if that would work.
Database Structure
Chat
-ChatID
-LIYv8kWHEZ7udgM048U
-LIYv9t5jNmR8RXPht-p
-LIYxzbhbfkItT3FAsWB
createdByUser: "T3Wb0pHSfCTaIA2ofQSxc915wK83"
text: "Hey"
timestamp: "Aug 19"
-LIaJaAGG-jwD0i_bAqL
createdByUser: "T3Wb0pHSfCTaIA2ofQSxc915wK83"
text: "Yoooo"
timestamp: "Aug 20"
you can do the following
chatRef.orderByChild("ChatID").limitToLast(1).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String key = dataSnapshot.getKey();
}
#Override
public void onCancelled(DatabaseError databaseError) {
System.out.println("The read failed: " + databaseError.getCode());
}
});
Where chatRef
DatabaseReference mDatabase,chatRef;
mDatabase = FirebaseDatabase.getInstance().getReference();
chatRef = mDatabase.child("Chat");
I was able to solve using this
final DatabaseReference ChatDB = mDatabaseChat.child("ChatID");
final Query lastQuery = ChatDB.orderByKey().limitToLast(1);
ChatDB.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
lastQuery.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot child: dataSnapshot.getChildren()){
String key = child.child("text").getValue().toString();
I have a Firebase database of the following:
Root Node
User node
an automatically generated key generated by ref.push()
attributes
I am trying to retrieve only one of the attributes of a single child under the user. Here is a screenshot of my database:
Screenshot of my database
If you check the screenshot, i only want to retrieve email (assume i have no other way of getting it). However, in the code, I wouldn't know the child of User that contains the email I want. This is what i am currently doing but it is very inefficient (this code checks if my current user exists, if not, it adds his/her data to the database):
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("User");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Iterable<DataSnapshot> children = dataSnapshot.getChildren();
for (DataSnapshot child:children) {
User user1 = child.getValue(User.class);
Log.d("kharas email",user1.getEmail()+"");
if(!user1.getEmail().equals(firebaseAuth.getCurrentUser().getEmail())){
GraphRequest.newMeRequest(token, new GraphRequest.GraphJSONObjectCallback() {
String birthday = "Not Available";
#Override
public void onCompleted(JSONObject object, GraphResponse response) {
User userInfo = new User();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("User");
birthday = object.has("email")+"";
userInfo.setBirthday(birthday);
userInfo.setEmail(firebaseAuth.getCurrentUser().getEmail());
ref.push().setValue(userInfo);
}
}).executeAsync();
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
I tried to set the child under User to the email but firebase wouldnt let me use some special characters in the key. Any suggestions to make the code more efficient would be appreciated. Or any key suggestions that would make querying easier would be great.
Thanks in advance
Instead of putting random value or auto generated key you can add user's id which is received from fire base
firebaseAuth.getCurrentUser().getUid()
This will be more easy to access and will be more efficient because whenever you get will logged in, you will have this user_id and corresponding to user_id you can get email instead of checking all values in database
The only way to retrieve email if you dont know the random key is this:
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("User");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot datas: dataSnapshot.getChildren()){ for (DataSnapshot child:children) {
String email=datas.child("email").getValue().toString();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Or you can use firebase authentication and add the userid under Users instead of push() then retrieve the userid :
FirebaseUser user=FirebaseAuth.getInstance().getCurrentUser();
String userid=user.getUid();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("User");
ref.child(userid).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String email=dataSnapshot.child("email").getValue().toString();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
That way you do not have to loop.
Hi I am trying to display data from multiple nodes in my database on a listview.
What I'm trying to do is display the "detailCategory" and "detailValue" for every type of workout, every time its saved.
Here is the database reference i'm currently using for my app.
currentUserDB = FirebaseDatabase.getInstance().getReference("WorkoutDetails").child("Cardio").child(currentUId);
I know this needs to increment into the further nodes, but i'm not sure how to read from multiple nodes from at one time.
I'm using dataSnapshot to read the data. I have data being read by specific date in another page, using the code below. So the problem might just be with the database reference in this case.
#Override
protected void onStart() {
super.onStart();
currentUserDB.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
cardiosList.clear();
for(DataSnapshot cardioHistorySnapshot : dataSnapshot.getChildren()){
Cardio cardio = cardioHistorySnapshot.getValue(Cardio.class);
cardiosList.add(cardio);
}
CardioHistoryList adapter = new CardioHistoryList(Cardio_History.this, cardiosList);
ListViewCardioHistory.setAdapter(adapter);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
As I saw in your comment, that you are "going as far as the date node", according to this, to display the detailCategory and the detailValue, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference dateRef = rootRef.child("WorkoutDetails").child("Cardio").child(currentUId).child(date);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot dSnapshot : dataSnapshot.getChildren()) {
for(DataSnapshot ds : dSnapshot.getChildren()) {
String detailCategory = ds.child("detailCategory").getValue(String.class);
String detailValue = ds.child("detailValue").getValue(String.class);
Log.d("TAG", detailCategory + " / " + detailValue);
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
dateRef.addListenerForSingleValueEvent(eventListener);
Where the date is the date under the currentUId, which can be 1-3-2018, 2-3-2018 and so on. And as you can see, to achieve this, we needed to use nested queries.
Users is my root node, in that I have various childs created by getting the uid of the user who authenticated. Within these childs (uid) their are various childs like Info, General maintenance, Complaints.
I want to show some of the details like gCity, gProductModel from General maintenance child from all the users (uids). Each uid will have a different values of gCity, etc. Under General Maintenance, I want to retrieve all that data by setting it on an adapter and listview.
I am not able to retrieve it.
Database image
retreive code
When i am trying to retrieve data from the current user by using 'getuid()'(As shown below) ,its working fine . But when i try to retrieve all users data using' getkey()' , it isn't working .
user = FirebaseAuth.getInstance().getCurrentUser();
ref= FirebaseDatabase.getInstance().getReference("Users")
.child(user.getUid())
.child("General Maintenance");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if(list_users.size() > 0)
list_users.clear();
for(DataSnapshot postSnapshot:dataSnapshot.getChildren())
{
Generalperson user =
postSnapshot.getValue(Generalperson.class);
list_users.add(user);
}
if(list_users.size() != 0)
{ ListViewAdapter adapter = new
ListViewAdapter(ServicehistoryActivity.this, list_users);
list_data.setAdapter(adapter);}
else
{
list_data.setVisibility(View.INVISIBLE);
k.setVisibility(View.VISIBLE);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Please use this code:
DatabaseReference usersRef = FirebaseDatabase.getInstance().getReference().child("Users");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String userId = ds.getKey();
DatabaseReference userIdRef = FirebaseDatabase.getInstance().getReference().child("Users").child(userId);
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.child("General Maintenence").getChildren()) {
String gCity = ds.child("gCity").getValue(String.class);
String gEmail = ds.child("gEmail").getValue(String.class);
String gPhone = ds.child("gPhone").getValue(String.class);
//and so on
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
userIdRef.addListenerForSingleValueEvent(valueEventListener);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
usersRef.addListenerForSingleValueEvent(eventListener);
If you get this error, Listen at /Users failed: DatabaseError: Permission denied is because you are not authorized to the Database, check the Rules Tab in the Realtime database and make this change:
{
"rules": {
".read": true,
".write":true
}
}
Hope it helps.