How to display nested objects in firebase data

Question

How to display the below data in a view:

[
  "parties" {
    "2016-12-30" {
      "uid" {
        "name": "joe",
        "age": "32"
      },
      "uid" {
        "name": "kevin",
        "age": "29"
      }
    },
    "2016-12-25" {
      "uid" {
        "name": "ben"
        "age": "44"
      }
    }
  }
]

In my controller I have

var parties = [Party]()

DataService.ds.REF_PARTIES.observe(.value, with: { (snapshot) in

    if let snapshot = snapshot.children.allObjects as? [FIRDataSnapshot] {
        print(snapshot)
        for snap in snapshot {
            if let partyDict = snap.value as? [String: AnyObject] {
                let key = snap.key // the party date
                let party = Party(date: key, partyData: partyDict)
                self.parties.append(party)

            }
        }
    }
    self.tableView.reloadData()
})

class PartyFeedCell: UITableViewCell:

func configureCell(party: Party) {
 dateLabel.text = part.date // date as expected
}

In react, I could use Object.key to go deeper in the loop and get the users for those dates (keys). Any way to accomplish this? Under, say xxx date, I should see a list of users.

Party.swift:

import Foundation

class Party {
  private var _name: String!
  private var _age: String!

  var name: String {
    return _name
  }

  [...]

  init(name: String, age: String) {
    self._name = name
    self._age = age
  }

  init(date: String, partyData: [String: AnyObject]) {
    self._date = date
    [...]
  }
}

DataService.swift:

import Foundation
import FirebaseDatabase

let DB_BASE = FIRDatabase.database().reference()

class DataService {

  static let ds = DataService()
  private var _REF_BASE = DB_BASE
  private var _REF_PARTIES = DB_BASE.child("parties").queryOrderedByKey()

  var REF_BASE: FIRDatabaseReference {
   return _REF_BASE 
  }

  var REF_PARTIES: FIRDatabaseQuery {
   return _REF_PARTIES
  }


}

Your question asks grouped by date, but your Firebase structure does not include and dates. Perhaps you mean by age? It also looks like you have duplicate keys uniqueDates under the parties node, which can't happen. — Jay
– Jay, Commented Dec 31, 2016 at 14:29
@Jay Hi. Yes, the dates will be unique. What really want is, how to display that information. — Sylar
– Sylar, Commented Dec 31, 2016 at 14:45
I think you missed my point. You can't sort, order or search by dates because there are NO dates in your Firebase structure. Please fix your question or structure to contain a date. Also, the question is no longer a question so it's unclear what you are asking, please update that as well. — Jay
– Jay, Commented Dec 31, 2016 at 15:15

Jay · Accepted Answer · 2016-12-31 16:05:23Z

1

Two things:

Using dates as key's... while it may be ok, should probably be changed - best practice is to disassociate keys from the data contained in the children.

parties
  -Y9809s0asas
     date: "2016-12-30"
     users:
       uid_0: true
       uid_1: true
  -Y89js99skks
     date: "2016-12-15"
     users:
       uid_1: true
       uid_3: true

users
  uid_0:
    name: "ben"
    age: "42"
  uid_1:
    name: "frank"
    age: "28"
  etc

The keys within parties are generated by childByAutoId (Y9809s0asas etc)

Second thing is that the code looks pretty much ok. The question appears to be how to get a value from a Dictionary?

In this case the code assigns the snap.value as a dictionary of [String: AnyObject] to partyDict. So at that point partyDict is just a Dictionary of key:value pairs

So in your Party class just a simple assignment is all that needs to be done:

  init(date: String, partyData: [String: AnyObject]) {
    self._date = date
    self._age = partyData["age"]
    self._name = partyData["name"]
  }

I didn't run your code but it's pretty close to being usable.

Oh - with this change in structure you will want to add one more property to the Party class, key. Make sure you pass the parent node name (snap.key) into the class so if it needs to be updated etc it will have the parent node name stored (the Y9809s0asas from the above structure)

edited Dec 31, 2016 at 16:05

answered Dec 31, 2016 at 15:59

Jay

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1 Comment

Sylar Over a year ago

Thanks. Let me get back to you.

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