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Current user to string

I faced a problem with showing data. Before I used current users UID as a key but now I'm using the custom key and I don't know how to call this key as a string in my code.
My code this part ( child(user.getUid() )
FirebaseUser userUID;
userUID = FirebaseAuth.getInstance().getCurrentUser();
final DatabaseReference NameRef = database.getReference().child("No server").child(userUID.getUid()).child("name");
final DatabaseReference LastNameRef = database.getReference().child("No server").child(userUID.getUid()).child("lastName");
final DatabaseReference EmailRef = database.getReference().child("No server").child(userUID.getUid()).child("email");
What changed
I want make user a string "dan ned".
Edit:
FirebaseDatabase database = FirebaseDatabase.getInstance();
final DatabaseReference NameRef = database.getReference().child("No server").child(user.getUid()).child("name");
final DatabaseReference LastNameRef = database.getReference().child("No server").child(user.getUid()).child("lastName");
final DatabaseReference EmailRef = database.getReference().child("No server").child(user.getUid()).child("email");
NameRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
final String strName = dataSnapshot.getValue(String.class);
textName.setText(strName);
}
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
LastNameRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
final String strLastName = dataSnapshot.getValue(String.class);
textLastName.setText(strLastName);
}
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
EmailRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
final String strEmail = dataSnapshot.getValue(String.class);
textEmail.setText(strEmail);
}
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});

There is no need to attach three listeners in order to read those three values. You can use only one, as you can see in the following lines of code:
String name = FirebaseAuth.getInstance().getCurrentUser().getDisplayName();
DatabaseReference db = FirebaseDatabase.getInstance().getReference();
DatabaseReference nameRef = db.child("No server").child(name);
nameRef.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
#Override
public void onComplete(#NonNull Task<DataSnapshot> task) {
if (task.isSuccessful()) {
DataSnapshot snapshot = task.getResult();
String key = snapshot.getKey();
Log.d("TAG", key); //It will print "dan ned"
String email = snapshot.child("email").getValue(String.class);
Log.d("TAG", email); //It will print "DanilNed#gmail.com"
String lastName = snapshot.child("lastName").getValue(String.class);
Log.d("TAG", lastName); //It will print "Ned"
String name = snapshot.child("name").getValue(String.class);
Log.d("TAG", name); //It will print "Dan"
} else {
Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
}
}
});

Firebase - getValue in third child return null

I have a problem, when I want get value from firebase, getValue() return null
DataSnapshot appleSnapshot and DataSnapshot dataSnapshot - in console I see Key and Value correctly in Firebase too
Database Structure
Debugging
DataSnapshot setting - return Key but don't return Value (null)
String settingKey - return correctly String Key
String settingValue - return null
Why i cant get Value from my deeper childs?
private void readData(final ValidateJoinInterface validateJoinInterface, final String name, final String password, final String user) {
DatabaseReference ref = FirebaseDatabase.getInstance().getReference();
ref.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot appleSnapshot : dataSnapshot.getChildren()) {
DataSnapshot setting = appleSnapshot.child(name).child("Settings").child("Password");
String settingKey = (String) appleSnapshot.child(name).child("Settings").child("Password").getKey();
String settingValue = (String) appleSnapshot.child(name).child("Settings").child("Password").getValue();
}
validateJoinInterface.validateJoin(correctName, correctPassword, correctUserId);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.e("DTAG", "onCancelled", databaseError.toException());
}
});
}

Assuming that the name varaible holds a String value like in your example Aa and also assuming that Aa is a direct child of your Firebase root, to solve this, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference settingsRef = rootRef.child(name).child("Settings");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String name = dataSnapshot.child("Name").getValue(String.class);
String password = dataSnapshot.child("Password").getValue(String.class);
Log.d("TAG", name + " / " + password);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
settingsRef.addListenerForSingleValueEvent(valueEventListener);
The output will be: Aa / Aaa.

You can getting any value like :
FirebaseDatabase.getInstance().getReference().child(name).child("Settings").child("Password")
.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot messageSnapshot : dataSnapshot.getChildren()) {
Log.d(TAG,"KEY - "+messageSnapshot.getKey() + "VALUE - "+messageSnapshot.getValue());
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
Crashlytics.logException(databaseError.toException());
sendMessageListener.onSendMessageFailure(databaseError.getMessage());
}
});

Firebase realtime database - how to get parent name based on a value of one of its keys

The structure looks like this:
users
|----username1
|----uid:value
username2
|----uid:value
I'm trying to find the best way to get the username value based of the value of it's uid,
This need to be in Java code (Android), So far I found the following code:
Query uid = reference.child("users").orderByChild("uid").equalTo(uid);
uid.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot datas: dataSnapshot.getChildren()){
String keys=datas.getKey();
if (keys.equals(uid)) {
// uid found
} else {
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});

Try this code and create a model class to fetch value of Uid
DatabaseReference users= FirebaseDatabase.getInstance().getReference().child("users");
users.orderByChild("uid").equalTo(uid).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot post:dataSnapshot.getChildren()){
//Use a model class to fetch user id like below
UIDDetails u=post.getValue(UIDDetails.class);
String user_id=u.getUid();
//Here all values will be equal to youy required uid if exists more than one
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});

Please add below code into your file:
DatabaseReference users= FirebaseDatabase.getInstance().getReference().child("users");
final Query userQuery = users.orderByChild("uid");
userQuery.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
map.clear();
if(child.getkey().toString().equalsIgnoreCase(uid)){
//Get the node from the datasnapshot
String myParentNode = dataSnapshot.getKey();
for (DataSnapshot child: dataSnapshot.getChildren())
{
String key = child.getKey().toString();
String value = child.getValue().toString();
map.put(key,value);
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
databaseError.toException();
}
});

Firebase Data retrieval in array

This is my Firebase realtime database structure:
How to get these data in a List to pass the data to the Model Class.
When I tried by generation data like below and it works.
listCourse = new ArrayList<>();
listCourse.add(new CourseModel("UserID", "CourseCode", "CourseName"));
listCourse.add(new CourseModel("122345", "TMN1234","System Programming"));
I just want get the data from firebase in this format..

You can retrieve list by this method.
Firebase ref = new Firebase(FIREBASE_URL);
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
Log.i("Count " ,""+snapshot.getChildrenCount());
for (DataSnapshot postSnapshot: snapshot.getChildren()) {
CourseModel course = postSnapshot.getValue(CourseModel.class);
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
Log.e("The read failed: " ,firebaseError.getMessage());
}
});
Please refer this documentation: https://firebase.google.com/docs/database/android/lists-of-data

if (dataSnapshot.exists()) {
int i = 1;
for (DataSnapshot dataSnapshot1 : dataSnapshot.child(userID).child("Course").getChildren()) {
coursecode[i]= dataSnapshot1.getKey();
coursename[i]=dataSnapshot.child(userID).child("Course").child(coursecode[i]).child("CourseName").getValue(String.class);
listCourse.add(new CourseModel(userID,coursecode[i],coursename[i]));
i++;
}
}
I figured it out.. this is working for me..

To Access Child you can to create reference.!
DatabaseReference userRef= FirebaseDatabase.getInstance().getReference("users");
DatabaseReference userChildRef= userRef.child(childId);
DatabaseReference userCourseRef= userChildRef.child("courses");
DatabaseReference userCourseIdRef= userCourseRef.child(courseId);
userCourseIdRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.i(TAG, dataSnapshot.getValue(String.class);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.w(TAG, "onCancelled", databaseError.toException());
}
});

Tol solve this, there are to ways. First would be to get the data as objects of CourseModel class like this:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference coursesRef = rootRef.child("Users").child(uid).child("Courses");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
List<CourseModel> list = new ArrayList<>();
for(DataSnapshot ds : dataSnapshot.getChildren()) {
CourseModel courseModel = ds.getValue(CourseModel.class);
list.add(courseModel);
}
//Do what you need to do with the list of CourseModel objects
Log.d("TAG", list.ToString);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
coursesRef.addListenerForSingleValueEvent(valueEventListener);
The second one, would be to get the courseName as a String like this:
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference coursesRef = rootRef.child("Users").child(uid).child("Courses");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
List<String> list = new ArrayList<>();
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String courseName = ds.child("CourseName").getValue(String.class);
list.add(courseName);
}
//Do what you need to do with the list of strings
Log.d("TAG", list.ToString);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
coursesRef.addListenerForSingleValueEvent(valueEventListener);

Reading Firebase data returns null Android

public void RetreiveNewQuestions(){
Random random = new Random();
int questionInt1;
questionInt1 = random.nextInt(2-1) + 1;
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
FirebaseDatabase.getInstance().getReference().child("questions").child("animal").child("1").child("question").addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String question1 = dataSnapshot.getValue(String.class);
question[0] = question1;
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
This method is supposed to read questions randomly, but first for testing purposes I tried to see if it can read one question, but did not work.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
questionRef = FirebaseDatabase.getInstance().getReference("questions");
category = "animal";
RetreiveNewQuestions();
String quizData[][] = {
//Format, {Question, right answer, option1, option2, option3}
{question[0], "Log", "Tree", "Knee"," Bee"},
{ "Potato", "Rar", "Laugh", "Test","Minute"}
};
What my data looks like in Firebase

If you want to get only the first question, then please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = rootRef.child("questions").child("animal").child("1");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String question = dataSnapshot.child("questions").getValue(String.class);
Log.d("TAG", question);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(valueEventListener);
If you want to get all the questions, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference animalRef = rootRef.child("question").child("animal");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String question = ds.child("question").getValue(String.class);
Log.d("TAG", question);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
animalRef.addListenerForSingleValueEvent(valueEventListener);