CODEWITHSUNDEEP
javaandroiddatabasefirebasefirebase-realtime-database
Arif Rahman
Arif Rahman

Reputation: 67

Android: Check List of data exists in Firebase Database or not

I am trying to make and app which will backup my contact list to firebase database. I can store all contacts into the database, but when I save new numbers and hit sync button again, it pushes all contacts again. I have the ArrayList of my contacts now I want to check each and every contacts if it already exists in firebase or not. If it does not exist, it should be inserted. 

public void SyncNow(View view) {
    final DatabaseReference root = FirebaseDatabase.getInstance().getReference();

    for (i=0; i<storeContacts.size(); i++){
        UserContact contact = storeContacts.get(i);
        final String number = contact.getContactNumber();
        Query query = root.child("contactList").orderByChild("contactNumber").equalTo(number);
        query.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                if (dataSnapshot.exists()){
                    //do nothing
                }else {
                    String key = root.push().getKey();
                    root.child("ContactList").child(key).setValue(contact);
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }

}

This code is adding only the last contact of my UserContact ArrayList for size of arraylist. I have 108 contact it pushing the last contact 108 times. Someone please help.

Upvotes: 2

Views: 621

Answers (2)

user4571931
user4571931

Reputation:

you used for each loop then i think all record will be add that does not have firebase database ..

    for (UserContact contact:storeContacts){

    }

Upvotes: 0

Alex Mamo
Alex Mamo

Reputation: 138824

To solve this, you need to do a little change in your database strcuture by saving those numbers as in the following database strcuture:

Firebase-root
   |
   --- phoneNumbers
          |
          --- phoneNumberOne
          |       |
          |       --- //details
          |
          --- phoneNumberTwo
          |       |
          |       --- //details
          |
          --- phoneNumberThree
                  |
                  --- //details

Now it's very simply to check a number for existens.

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference phoneNumberToCheckRef = rootRef.child("phoneNumbers").child(phoneNumberToCheck");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        if(!dataSnapshot.exists()) {
            //Add number
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
phoneNumberToCheckRef.addListenerForSingleValueEvent(valueEventListener);

Upvotes: 1

Related Questions