Adding listener to firebase having List like data

Question

I have this structure in Firebase

    "shared_items" : {
    "-KgGHdgE3L_m6ppVgn99" : {
      "_id" : 14,
      "added_date" : "08/Mar/2017",
      "shared_with_emails" : "{\"abc@abc*com\":{\"name\":\"Customer Care\"},\"xyz@xyz*com\":{\"name\":\"Customercare\"}}",
      "user_display_name" : "Logged in user",
      "users_email" : "loggedinUser@gmail.com"
    }
  }

My questions:

1. When I am saving JSON data in "shared_with_emails" key then my data is automatically appended with "\" slash. Is this normal or I am doing something wrong here?
2. How can I get entire node based on email Ids present in this JSON object.

Function to create JSON objects from provided contacts..

public class JsonUtils {
    final private static String TAG = JsonUtils.class.getSimpleName();

    public String ContactsToJson() {
        ArrayList<ContactsModel> listOfContacts = new ArrayList<>();
        listOfContacts.add(new ContactsModel("abc@gmail.com", "abc"));
        listOfContacts.add(new ContactsModel("xyz@gmail.com", "xyz"));
        listOfContacts.add(new ContactsModel("mnop@yahoo.com", "mnop"));


        JSONObject jsonObjectChild;
        JSONObject jsonObjectRoot = new JSONObject();

        for (int i = 0; i < listOfContacts.size(); i++) {
            ContactsModel model = (ContactsModel) listOfContacts.get(i);
            try {
                jsonObjectChild = new JSONObject();
                jsonObjectChild.put("name", model.getContactName());
                jsonObjectRoot.put(model.getContactMail(), jsonObjectChild);
            } catch (JSONException e){
                e.printStackTrace();
            }

        }

        System.out.println(jsonObjectRoot.toString());
        return jsonObjectRoot.toString();
    }

    public class ContactsModel {

        private int id;
        private String mContactName;
        private String mContactMail;


        public ContactsModel(String contactMail, String contactName) {
            this.mContactName = contactName;
            this.mContactMail = contactMail;
        }

        public String getContactName() {
            return mContactName;
        }

        public String getContactMail() {
            return mContactMail;
        }
    }

}

Json data on Firebase

Answer 1

You can use ArrayList<String> to have multiple emails saved under shared_with_email. When you retrieve your data, save it inside an object and search whether the object contains the email.

ArrayList<String> keys = new ArrayList<>;

rootRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for(Datasnapshot snap:datasnapshot.getChildren()){
                ArrayList<yourObject> current = snap.getValue();
                if (current.shared_with_email.contains(someEmail)){
                    keys.add = snap.getKey(); //Check this, all we need is the key of our object. kd47qjB.... in this case
                } 
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

Once you have all the keys. Add listeners.

for(String key: keys){
    rootRef.child(key).addValueEventListener(new ValueEventListener(){
        @override
        public void onDataChange(Datasnapshot datasnapshot){
            //You successfully added listener to the key where user has its email. 
            //Do your work here.
        }
    });
}

You will have to create a class yourObject which resembles the data in your firebase database.