when quering the database has the object but getValue() will return null

I keep user per unique value into real time firebase as display at this link image:
get user according to email - database firebase
I want to get user by email
so I try to doing that like this:

 private void getUserFromRealtimeFirebase(String email) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);



    query.addValueEventListener(new ValueEventListener() {

        @Override

        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            Log.i("TAG", "dataSnapshot value = " + dataSnapshot.getValue().toString());



            if (dataSnapshot.exists()) {

                Log.d("Tag", "user exists"); 

            }

        }



        @Override

        public void onCancelled(@NonNull DatabaseError databaseError) {



        }

    });

}

but I always get at callback listener: dataSnapshot: key = user , value = null even when email exists.

enter image description here

I wander what wrong?

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

add a comment |

I keep user per unique value into real time firebase as display at this link image:
get user according to email - database firebase
I want to get user by email
so I try to doing that like this:

 private void getUserFromRealtimeFirebase(String email) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);



    query.addValueEventListener(new ValueEventListener() {

        @Override

        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            Log.i("TAG", "dataSnapshot value = " + dataSnapshot.getValue().toString());



            if (dataSnapshot.exists()) {

                Log.d("Tag", "user exists"); 

            }

        }



        @Override

        public void onCancelled(@NonNull DatabaseError databaseError) {



        }

    });

}

but I always get at callback listener: dataSnapshot: key = user , value = null even when email exists.

enter image description here

I wander what wrong?

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

add a comment |

I keep user per unique value into real time firebase as display at this link image:
get user according to email - database firebase
I want to get user by email
so I try to doing that like this:

 private void getUserFromRealtimeFirebase(String email) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);



    query.addValueEventListener(new ValueEventListener() {

        @Override

        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            Log.i("TAG", "dataSnapshot value = " + dataSnapshot.getValue().toString());



            if (dataSnapshot.exists()) {

                Log.d("Tag", "user exists"); 

            }

        }



        @Override

        public void onCancelled(@NonNull DatabaseError databaseError) {



        }

    });

}

but I always get at callback listener: dataSnapshot: key = user , value = null even when email exists.

enter image description here

I wander what wrong?

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

I keep user per unique value into real time firebase as display at this link image:
get user according to email - database firebase
I want to get user by email
so I try to doing that like this:

 private void getUserFromRealtimeFirebase(String email) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);



    query.addValueEventListener(new ValueEventListener() {

        @Override

        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            Log.i("TAG", "dataSnapshot value = " + dataSnapshot.getValue().toString());



            if (dataSnapshot.exists()) {

                Log.d("Tag", "user exists"); 

            }

        }



        @Override

        public void onCancelled(@NonNull DatabaseError databaseError) {



        }

    });

}

but I always get at callback listener: dataSnapshot: key = user , value = null even when email exists.

enter image description here

I wander what wrong?

firebase firebase-realtime-database

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

edited Jan 20 at 14:07

asked Jan 17 at 15:17

Yaffa

2517

asked Jan 17 at 15:17

Yaffa

2517

asked Jan 17 at 15:17

Yaffa

2517

add a comment |

1 Answer
1

active

oldest

votes

EDIT:

If you don't want to pass userId, use this query:

mDatabaseReference = mFirebaseDatabase.getReference();

Query query = mDatabaseReference.orderByChild("user/email").equalTo(email);

You are missing the user-id level.
You should change your code to:

private void getUserFromRealtimeFirebase(String email, String userId) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().chlid(userId).child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);

...

...

}

Btw I would consider re-arranging the data structure to -
newsapp -> users -> {userId} -> {name, image, firebase-token, email....}.

Also, on the callback - first check if dataSnapshot.exists() and only after that use getValue(), even if inside a log, to avoid null pointer exception.

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

add a comment |

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1 Answer
1

active

oldest

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1 Answer
1

active

oldest

votes

EDIT:

If you don't want to pass userId, use this query:

mDatabaseReference = mFirebaseDatabase.getReference();

Query query = mDatabaseReference.orderByChild("user/email").equalTo(email);

You are missing the user-id level.
You should change your code to:

private void getUserFromRealtimeFirebase(String email, String userId) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().chlid(userId).child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);

...

...

}

Btw I would consider re-arranging the data structure to -
newsapp -> users -> {userId} -> {name, image, firebase-token, email....}.

Also, on the callback - first check if dataSnapshot.exists() and only after that use getValue(), even if inside a log, to avoid null pointer exception.

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

add a comment |

EDIT:

If you don't want to pass userId, use this query:

mDatabaseReference = mFirebaseDatabase.getReference();

Query query = mDatabaseReference.orderByChild("user/email").equalTo(email);

You are missing the user-id level.
You should change your code to:

private void getUserFromRealtimeFirebase(String email, String userId) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().chlid(userId).child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);

...

...

}

Btw I would consider re-arranging the data structure to -
newsapp -> users -> {userId} -> {name, image, firebase-token, email....}.

Also, on the callback - first check if dataSnapshot.exists() and only after that use getValue(), even if inside a log, to avoid null pointer exception.

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

add a comment |

EDIT:

If you don't want to pass userId, use this query:

mDatabaseReference = mFirebaseDatabase.getReference();

Query query = mDatabaseReference.orderByChild("user/email").equalTo(email);

You are missing the user-id level.
You should change your code to:

private void getUserFromRealtimeFirebase(String email, String userId) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().chlid(userId).child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);

...

...

}

Btw I would consider re-arranging the data structure to -
newsapp -> users -> {userId} -> {name, image, firebase-token, email....}.

Also, on the callback - first check if dataSnapshot.exists() and only after that use getValue(), even if inside a log, to avoid null pointer exception.

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

EDIT:

If you don't want to pass userId, use this query:

mDatabaseReference = mFirebaseDatabase.getReference();

Query query = mDatabaseReference.orderByChild("user/email").equalTo(email);

You are missing the user-id level.
You should change your code to:

private void getUserFromRealtimeFirebase(String email, String userId) {

    mFirebaseDatabase = FirebaseDatabase.getInstance();

    mDatabaseReference = mFirebaseDatabase.getReference().chlid(userId).child("user");

    Query query = mDatabaseReference.orderByChild("email").equalTo(email);

...

...

}

Btw I would consider re-arranging the data structure to -
newsapp -> users -> {userId} -> {name, image, firebase-token, email....}.

Also, on the callback - first check if dataSnapshot.exists() and only after that use getValue(), even if inside a log, to avoid null pointer exception.

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

edited Jan 20 at 14:57

answered Jan 20 at 14:28

Orit Malki

606

answered Jan 20 at 14:28

Orit Malki

606

answered Jan 20 at 14:28

Orit Malki

606

add a comment |

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