Firebase push data on same child using Hashmap

Question

For my android application i'm trying to add multiple strings to the same child (Firebase Unique ID) in which the user will enter on different layouts. I'm using a Hashmap to put the strings into Firebase. I have 4-5 different layouts that the user would come across and needs to fill out the information, but when I save it in the Database, it always goes under a different Unique ID and I need it all to be under the same one.

Here's my code, I created a Parent class with every layout (the other classes) having some method to access the Hashmap.

Parent Class:

public class FireBaseDataMap {

    private HashMap<String, String> dataMap = new HashMap<String, String>();

    public HashMap<String, String> fireebaseMap(){
        return dataMap;
    }

}

First Activity: I put an arrow where I needed help in the onClick(View view) method.

    public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    //UI References
    private EditText firstName;
    private EditText lastName;
    private EditText birthPlace;
    private EditText etxtBirthdate;
    private EditText etxtMissingDate;
    private Button saveButton;
    private Button cancel_button;


    private DatePickerDialog birthdateDatePickerDialog;
    private DatePickerDialog missingDatePickerDialog;

    private DatabaseReference mDatabase;

    private SimpleDateFormat dateFormatter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        dateFormatter = new SimpleDateFormat("dd-MM-yyyy", Locale.US);

        findViewsById();

        setDateTimeField();

        saveButton = (Button) findViewById(R.id.saveButton);
        cancel_button = (Button) findViewById(R.id.cancel_button);

        saveButton.setOnClickListener(this);
        cancel_button.setOnClickListener(this);

    }

    private void findViewsById() {

        firstName = (EditText) findViewById(R.id.firstName);
        lastName = (EditText) findViewById(R.id.lastName);
        birthPlace = (EditText) findViewById(R.id.birthPlace);


        etxtBirthdate = (EditText) findViewById(R.id.etxt_birthdate);
        etxtBirthdate.setInputType(InputType.TYPE_NULL);
        etxtBirthdate.requestFocus();


        etxtMissingDate = (EditText) findViewById(R.id.etxt_missingdate);
        etxtMissingDate.setInputType(InputType.TYPE_NULL);
        etxtMissingDate.requestFocus();


    }

    @Override
    public void onClick(View view) {
        if(view == etxtBirthdate) {
            birthdateDatePickerDialog.show();
        }

        if(view == etxtMissingDate){
            missingDatePickerDialog.show();
        }
        if(view == saveButton){

            String FirstName = firstName.getText().toString().trim();
            String LastName = lastName.getText().toString().trim();
            String BirthPlace = birthPlace.getText().toString().trim();
            String BirthDate = etxtBirthdate.getText().toString().trim();
            String MissingDate = etxtMissingDate.getText().toString().trim();

            mDatabase = FirebaseDatabase.getInstance().getReference();

            // Here is where im accessing the parent class and need help <------
            FireBaseDataMap obj = new FireBaseDataMap();
            HashMap<String, String> dataMap = obj.fireebaseMap();

            if(FirstName.isEmpty()) {
                FirstName = "n/a";
                dataMap.put("firstName", FirstName);
            }
            else
                dataMap.put("firstName", FirstName);

            if(LastName.isEmpty()) {
                LastName = "n/a";
                dataMap.put("lastName", LastName);
            }

            else
                dataMap.put("lastName", LastName);

            if(BirthPlace.isEmpty()) {
                BirthPlace = "n/a";
                dataMap.put("birthPlace", BirthPlace);
            }

            else
                dataMap.put("birthPlace", BirthPlace);

            if(BirthDate.isEmpty()) {
                BirthDate = "n/a";
                dataMap.put("birthDate", BirthDate);
            }

            else
                dataMap.put("birthDate", BirthDate);

            if(MissingDate.isEmpty()) {
                MissingDate = "n/a";
                dataMap.put("missingDate", MissingDate);
            }

            else
                dataMap.put("missingDate", MissingDate);


            mDatabase.child("null").push().setValue(dataMap);

        }

        if(view == cancel_button){
            startActivity(new Intent(this, PhysicalAttributes.class));

        }
    }

}

Second Activity: I'm just posting the method where I need help on for this activity so it wont seem so long, but if need the full class to understand then I can update it.

 public void onClick(View view) {



        if (view == saveButton) {


            String PersonAge = personAge.getText().toString().trim();
            String PersonHeight = personHeight.getText().toString().trim();
            String PersonWeight = personWeight.getText().toString().trim();

            mDatabase = FirebaseDatabase.getInstance().getReference();

            FireBaseDataMap obj = new FireBaseDataMap();
            HashMap<String, String> dataMap = obj.fireebaseMap();


            if(PersonAge.isEmpty()){
                PersonAge = "n/a";
                dataMap.put("personAge", PersonAge);
            }

            else
                dataMap.put("personAge", PersonAge);

            if(PersonHeight.isEmpty()) {
                PersonHeight = "n/a";
                dataMap.put("personHeight", PersonHeight);
            }
            else
                dataMap.put("personHeight", PersonHeight);

            if(PersonWeight.isEmpty()) {
                PersonWeight = "n/a";
                dataMap.put("personWeight", PersonWeight);
            }
            else
                dataMap.put("personWeight", PersonWeight);

            mDatabase.child("null").push().setValue(dataMap);


        }
        if (view == cancel_button) {


        }

    }
}

I've tried looking all over and tried different ways to make it work, but nothing. Any help would be appreciated. If clarification is needed then will try my best.

Another way I was thinking of is if I can access the same saveButton on every activity if that'll work.

Answer 1

From what I understand, you want all the attributes under one node. Something like this

null
  |-------uniqueKey
           |------birthdate
           |------birthplace
           |------firstname
           |------lastname
           |------missingdate
           |------personAge
           |------personHeight
           |------personWeight

However, you are calling push. mDatabase.child("null").push().setValue(dataMap); What 'push' does is it literally pushes a new node on the database and and when you call setValue you add the dataMap to that new 'push key'. You should use push when working with lists of data. When you call push the first time it adds an new node to the 'null' child you made.

You get this

null
 |
-----FirstuniquePushKey

And in your second activity when you call push again, you get this

null
 |-------FirstUniqueyKey
 |         |--------
 |-------SecondUniqueKey
           |--------

If you want to add attributes to the same child(unique key). Traverse down to that node like this

   mDatabase.child("null").child("FirstUniqueKey").child("pesronAge").setValue('n/a')

This way you are not calling 'push' and therefore not creating a new 'push' key. You are at the firstuniqueKey node and you create another child called personAge and you set its value. I hope this makes sense.

Edit

You must be calling set value. If you are doing this,

mDatabase.child("null").child("FirstUniqueKey").setValue(HashMap). 

That is why it overwrites what you had you previously. You can achieve what you want in two ways

1) For each key you have in the second hashmap. Set the value.

    mDatabase.child("null").child("FirstUniqueKey").child("PersonAge").setValue('')

mDatabase.child("null").child("FirstUniqueKey").child("PersonHeight").setValue('')

 mDatabase.child("null").child("FirstUniqueKey").child("PersonWeight").setValue('')  

2)The second way to achieve it create a new pushKey.

mDatabase.child("null").child("FirstUniqueKey").push().setValue(HashMap)

Notice how I am at the child "FirstUniqueKey" and I push and then set the value.