Develop Reference

Get Value from Firebase Database

I need to get the string value from the node passcode in my Firebase database to compare with a user input, but unfortunately I am not able to get the value. This is the link to my firebase database in the below image.
This is my codes below:
final DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference("pin_code");
mDatabase.addListenerForSingleValueEvent(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
String rface = (String) dataSnapshot.child("pincode").getValue();
if (rface.equals(userPassword) && !rface.equals("")){
Intent intent = new Intent(PinActivity.this, ProfileActivity.class);
startActivity(intent);
}
else {
if (rface.equals("") || rface.equals(null)){
// Creating new user node, which returns the unique key value
// new user node would be /users/$userid/
String userId = mDatabase.push().getKey();
// creating user object
Pin pin = new Pin(authUserId, userPassword);
mDatabase.child(userId).setValue(pin);
Intent intent = new Intent(PinActivity.this, ProfileActivity.class);
startActivity(intent);
}
else {
Toast.makeText(PinActivity.this,"Invalid PIN code", Toast.LENGTH_SHORT).show();
return;
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
This is the json code
{
"pin_code" : {
"id" : "TQYTo1NHNnhPJnOxhe1Vok3U6ic2",
"pincode" : "12345"
}
}

This FirebaseDatabase.getInstance().getReference("pin_code") does not refer to the node you're looking for. Most likely you know the id property, in which case you can get the node with:
DatabaseReference collection = FirebaseDatabase.getInstance().getReference("p...");
Query query = collection.orderByChild("id").equalTo("TQT...ic2");
query.addListenerForSingleValueEvent(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
for (DataSnapshot child: dataSnapshot.getChildren()) {
String rface = (String) child.child("pincode").getValue();
if (rface.equals(userPassword) && !rface.equals("")){
The changes I made:
On the first line we get the collection: the node under which you want to run a query. You struck out the name of that node in the screenshot, but it's the second line you marked.
In the second line we create a query on the id property of each child node under the collection.
In the onDataChange we added a loop. This is needed because a query against the Firebase Database will potentially have multiple results. So the dataSnapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result. We loop over dataSnapshot.getChildren() to handle those multiple results.
If there can ever only be one node with the same id, you should consider changing your data structure to use the id as the key of the node. So:
pin_codes
uid1: "pincode1"
uid2: "pincode2"
Your code then becomes significantly simpler, because you don't need to query for the user anymore. You can just directly read from the path:
DatabaseReference user = FirebaseDatabase.getInstance().getReference("pin_codes").child("TQT...ic2");
user.addListenerForSingleValueEvent(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
String rface = (String) dataSnapshot.getValue();
if (rface.equals(userPassword) && !rface.equals("")){

Try change this:
String rface = (String) dataSnapshot.child("pincode").getValue();
To this:
String rface = (String) dataSnapshot.child("pincode").getValue(String.class);

Use the following::
Object some = dataSnapshot.getValue();
String value = some.toString();

How to get specific record from ArrayList stored in fireabase

I have stored ArrayList in firebase DB, is there any way to get specific record from firebase using particular id (memberId) from ArrayList
Currently, I'm able to get the tripMemberList ArrayList but I want to get specific record from ArrayList using memberId
I don't want to retrieve full ArrayList only need a single record from tripMemberList using memberId
I'm attaching a firebase DB structure below
Edit: How i add a record to firebase
TripChatDTO tripChatDTO = new TripChatDTO();
tripChatDTO.setTripId(jsonObject.getInt("travelId"));
tripChatDTO.setTripName(travelDTO.getTitle());
tripChatDTO.setTripPicUrl(jsonObject.getString("image"));
List<TripMemberDTO> memberDTOList = new ArrayList<>();
for (int i = 0; i < invitedFriendArray.length(); i++) {
JSONObject jsonObject1 = invitedFriendArray.getJSONObject(i);
TripMemberDTO dto = new TripMemberDTO();
dto.setMemberId(jsonObject1.getInt("id"));
dto.setAdmin(false);
dto.setNotification(true);
memberDTOList.add(dto);
}
// Add Admin record
TripMemberDTO tripMemberDTO = new TripMemberDTO();
tripMemberDTO.setMemberId(loggedInUser.getId());
tripMemberDTO.setAdmin(true);
tripMemberDTO.setNotification(true);
memberDTOList.add(tripMemberDTO);
// Add all Member record to travel
tripChatDTO.setTripMemberList(memberDTOList);
String channelName = "Trip-" + tripChatDTO.getTripId();
// Create tip
FirebaseDatabase.getInstance().getReference().child(TRIP).child(channelName).setValue(tripChatDTO);

it might be anywhere in the list I want to find a record using `memberId
Then loop over the children of the top element
tripMemberRef rootRef = FirebaseDatabase.getInstance().getReference()
.child("Trips/Trip-190/tripMemberList");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot c : dataSnapshot.getChildren()) {
String memberId = c.child("memberId").getValue(String.class);
Log.d("TAG", memberId);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(eventListener);

Assuming that Trips is a direct child of the Firebase root, please use this code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = rootRef.child("Trips").child("Trip-190").child("tripMemberList").child("0");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String memberId = dataSnapshot.child("memberId").getValue(String.class);
Log.d("TAG", memberId);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(eventListener);
But remember, Firebase is a NoSQL database which is structured as pairs of key and values. This means that every object within a Firebase database is a Map and not an ArrayList.

Firebase setValue not creating unique child node?

ArrayList<ListingModel> list = new ArrayList<ListingModel>();
list.add(model);
list.add(model2);
list.add(model3);
list.add(model4);
for (ListingModel m : list) {
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("node");
myRef.push().setValue(m);
}
I am trying to save 4 objects from android app to firebase database. So I am using loop to store data into the node. It should have create 4 different child with auto id and stored the object there . But it's only storing the last model in one unique id like image below :
How can I save all four objects(data in list) with unique id each?

Fully documented at firebase
private void writeNewPost(String userId, String username, String title, String body) {
// Create new post at /user-posts/$userid/$postid and at
// /posts/$postid simultaneously
String key = mDatabase.child("posts").push().getKey();
Post post = new Post(userId, username, title, body);
Map<String, Object> postValues = post.toMap();
Map<String, Object> childUpdates = new HashMap<>();
childUpdates.put("/posts/" + key, postValues);
childUpdates.put("/user-posts/" + userId + "/" + key, postValues);
mDatabase.updateChildren(childUpdates);
}
Put your models in a map, put them, and use updateChildren

The best way to do is to use for loop.
ArrayList<ListingModel> list = new ArrayList<ListingModel>();
list.add(model);
list.add(model2);
list.add(model3);
list.add(model4);
for (int i =0; i<list.size();i++){
ListingModel model = list.get(i);
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("node");
myRef.child(i).setValue(model);
}

So the problem was with how I set the model (Sorry for partial code in my question)
ListingModel model = new ListingModel();
model.setTitle("test0");
ListingModel model1 = new ListingModel();
model.setTitle("test1");
ListingModel model2 = new ListingModel();
model.setTitle("test2");
ListingModel model3 = new ListingModel();
model.setTitle("test3");
I was instantiating different models, but only altering value of first model.
model1, model2, and model3 was empty hence was not appearing in firebase database for being an empty object.

I think the code only read push once. And when you using the same id to write the data, you will overwrite the previous version.
ArrayList<ListingModel> list = new ArrayList<ListingModel>();
list.add(model);
list.add(model2);
list.add(model3);
list.add(model4);
for (ListingModel m : list) {
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("node");
String modelID = myRef.push().getKey();
myRef.child(modelID).setValue(m);
}
Try this, I hope it helps.
Btw, practice using updateChildren rather than setValue for saving your data.

Retrieve User Data Firebase on Android

Is there a way to retrieve data from a specific user who is authenticated via firebase through ID?
For example to retrieve information like name, photo etc.
Thanks in advance.

This is more of a port of the iOS answer i have given here
Firebase provides authentication for users using the FIRAuth Clases/API
However they can't be edited with custom fields like the Firebase Database.
To allow custom fields for user, you need to duplicate users in the Database with the same unique uid you receive in the auth of the user. Something like this
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
// User is signed in
String name = user.displayName;
String email = user.email;
String photoUrl = user.photoURL;
String uid = user.uid;
FirebaseDatabase database = FirebaseDatabase.getInstance();
String key = database.getReference("users").push().getKey();
Map<String, Object> childUpdates = new HashMap<>();
childUpdates.put( "uid", uid);
childUpdates.put( "name", name);
// other properties here
database.getReference("users").updateChildren(childUpdates, new DatabaseReference.CompletionListener() {
#Override
public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {
if (databaseError == null) {
}
}
});
}
We push it at the users end point in our db and with the uid key by the following line /users/\(key).
Now you can retrieve users detail from your database by querying anywhere in your code.

How to add new data in firebase android

This is my logic for adding new person in firebase realtime databse. But instead of making a new entry it is just updating the old data with new one.
buttonSave.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
/*
new Firebase(Config.FIREBASE_URL)
.push()
.child("title")
.setValue(text.getText().toString());
*/
Firebase ref = new Firebase(Config.FIREBASE_URL);
String name = editTextName.getText().toString().trim();
String address = editTextAddress.getText().toString().trim();
//Creating Person object
Person person = new Person();
//Adding values
person.setName(name);
person.setAddress(address);
ref.child("Person").setValue(person);
}
});
new Firebase(Config.FIREBASE_URL).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
for (DataSnapshot postSnapshot : snapshot.getChildren()) {
//Getting the data from snapshot
Person person = postSnapshot.getValue(Person.class);
//Adding it to a string
String string = "Name: "+person.getName()+"\nAddress: "+person.getAddress()+"\n\n";
//Displaying it on textview
textViewPersons.setText(string);
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
System.out.println("The read failed: " + firebaseError.getMessage());
}
});
What is wrong here? Can anyone help me on this?

You are using always the same ref
Person person = new Person();
//Adding values
person.setName(name);
person.setAddress(address);
ref.child("Person").setValue(person);
Check the doc:
Using setValue() in this way overwrites data at the specified location, including any child nodes.
In your case you are overriding the same data for this reason.
You should use the push() method to generate a unique ID every time a new child is added to the specified Firebase reference.
Person person = new Person();
//Adding values
person.setName(name);
person.setAddress(address);
DatabaseReference newRef = ref.child("Person").push();
newRef.setValue(person);

You can add a new Child to your data, such as:
mAuth = FirebaseAuth.getInstance();
FirebaseUser user = mAuth.getCurrentUser();
String userId = user.getUid();
Firebase rootRef = new Firebase(Config.USER_URL);
Firebase userRef = rootRef.child("Users");
Person newUser = new Person();
newUser.setFirstName(firstName);
newUser.setLastName(lastName);
userRef.child(userId).setValue(newUser);
The userId varies when the logging user is different, therefore, you will always go to a new data list for a new logged-in-user in the userId under Users.

every time when you optate to insert data to database call the follwing method.
You can integrate as many attributes you optate.It will engender a unique key everytime and insert records.
public void insert2database(double latitude,double longitude,String name) {
HashMap<String,String> student=new HashMap<>();
student.put("Name",name);
student.put("Lat", String.valueOf(latitude));
student.put("Long", String.valueOf(longitude));
student.put("Phone", String.valueOf("78787500000"));
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference tasksRef = rootRef.child("USERS").push();
tasksRef.setValue(student);
}
It will be in the database hierarchy like this
-database-4df17-default-rtdb
-USERS
-MUqgUu8zUpYcIaUVSsj
-Lat: "25.9405145"
-Long: "79.9100086"
-Name:"Dilroop"
-Phone: "78787500000"
-MUqoL2AUQFjH2ggKWev
-Lat: "32.9405145"
-Long: "73.9178186"
-Name: "Sanghavi"
-Phone: "78787500000"
-MUsfc-H-7KdQhrkHb_F
-Lat: "52.9405145"
-Long: "79.9175856"
-Name: "MDNSRF"
-Phone: "78787500000"

You are referencing to the "Person" child and setting it's value (setValue()) every time you click buttonSave, which only edits that one child. Try to use push() instead.