Query an array from Firestore

Question

I've some strings and 2 arrays stored in Firestore, and now I'm trying to receive them but I've no idea how. Well, the strings works fine, but I don't know how I can query the arrays. I'm getting the error code:

Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

And here is my code:

                            //For-loop
                        for document in QuerySnapshot!.documents
                        {
                            self.list.removeAll()
                            //let document = QuerySnapshot!.documents
                            let data = document.data()

                            let data1 = data["Dog"] as? String
                            let data2 = data["Person"] as? String
                            let data3 = data["What"] as? String
                            let data4 = data["Time"] as? String
                            let data5 = data["Date"] as? String
                            let data6 = data["Kilometers"] as? String
                            let data7 = data["Timer"] as? String
                            let data8 = data["Latitude"] as? Array<Double>
                            let data9 = data["Longitude"] as? Array<Double>

                            let txt = listTxt(dog: data1!, person: data2!, action: data3!, time: data4!, date: data5!, kilometers: data6!, timer: data7!, latitude: data8 ?? [], longitude: data9 ?? [])

                            print(txt)

                            tempTxt.append(txt)

                        }
                        self.list = tempTxt
                        self.tableView.reloadData()
                    }

The arrays are stored as Double, and the point is to receive it as a double, and convert it into CLLocationCoordinate2D again, so I can use the coordinates for a map. If you know how to solve this issue, please let me know. :)

Inside a class:

class listTxt
{
    var dog: String
    var person: String
    var action: String
    var time: String
    var date: String
    var kilometers: String
    var timer: String
    var latitude: [String]
    var longitude: [String]

    init(dog: String, person: String, action: String, time: String, date: String, kilometers: String, timer: String, latitude: [String], longitude: [String])
    {
        self.dog = dog
        self.person = person
        self.action = action
        self.time = time
        self.date = date
        self.kilometers = kilometers
        self.timer = timer
        self.latitude = latitude
        self.longitude = longitude
    }

Inside history-cell

    class HistoryCell: UITableViewCell
{

    @IBOutlet weak var DogName: UILabel!
    @IBOutlet weak var Person: UILabel!
    @IBOutlet weak var Action: UILabel!
    @IBOutlet weak var Date: UILabel!
    @IBOutlet weak var Time: UILabel!
    @IBOutlet weak var timer: UILabel!
    @IBOutlet weak var kilometer: UILabel!
    var latitude: [String] = []
    var longitude: [String] = []

    func setCell(list: listTxt)
    {
        DogName.text = list.dog
        Person.text = list.person
        Action.text = list.action
        Date.text = list.date
        Time.text = list.time
        timer.text = list.timer
        kilometer.text = list.kilometers
        latitude = list.latitude
        longitude = list.longitude
    }
}

Firestore data:

Thanks in advance. :)

@Saurabh You mean I should use "as? String" instead of Double? And than convert it to Int, and from int to Double? :) — , Mar 06 '19 at 11:28
No that will not work, as you might be getting the string value with decimal. Correct me if i am wrong. — Saurabh, Mar 06 '19 at 11:30
@Saurabh Yep, It's a CLLocationCoordinate2D from the beginning. Which I converted to insert the data to Firestore — , Mar 06 '19 at 11:34
Well you might be getting empty strings or nil values, and if you try to cast them to Double, will throw an error. So before casting, check whether the values are not empty or nil. — Saurabh, Mar 06 '19 at 11:41
Does the output of document data contains any key that has null/nil value? If so refer this question https://stackoverflow.com/questions/37606376/how-to-handle-json-null-values-in-swift — Saurabh, Mar 06 '19 at 11:52
@Saurabh https://imgur.com/a/zP6S6uL This is the result atm. — , Mar 06 '19 at 12:00
I changed it back to [Double], and after all I added print(data8 ?? 0.0) to try, but all of them is returning 0.0, and at least one of them have latitude and longitude that is not 0. — , Mar 06 '19 at 12:23
what type of value are you receiving for the keys latitude and longitude, is it a string or an array? — Saurabh, Mar 06 '19 at 12:27
can you share the data that you are fetching from firestore? — Saurabh, Mar 06 '19 at 12:35
Check the edit in my thread, maybe theres wrong somewhere else — , Mar 06 '19 at 12:48
No problem in both classes. Can you show the output you get after printing document.data() in your console? — Saurabh, Mar 06 '19 at 12:57
replace both keys Latitude to latitude and Longitude to longitude in code — Saurabh, Mar 06 '19 at 13:04

Saurabh · Accepted Answer · 2019-03-06T13:16:21.183

3

Try replacing the following lines of code :

let data8 = data["latitude"] as? [Double]
let data9 = data["longitude"] as? [Double]

Cause: Accessing data with wrong keys

edited Mar 06 '19 at 13:16

answered Mar 06 '19 at 13:09

Saurabh

704
1
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Abu Ul Hassan · Answer 2 · 2019-03-06T13:10:24.033

-1

have you tried like below?

 let data8 = data["latitude"] as? [Double]
 let data9 = data["longitude"] as? [Double]

Actually you are accessing data with wrong keys... "latitude" , "longitude" are valid keys but you are retrieving with "Latitude" , "Longitude" which does not exist in your data snapshot

Note Please check when storing data you are sending it in form of array of double.

edited Mar 06 '19 at 13:10

answered Mar 06 '19 at 12:16

Abu Ul Hassan

1,076
8
24

This is when I'm saving it: ` var latitudes:[Double] = [] var longitudes:[Double] = []` I'll try what you said, but I think I already tried that tho :/ – Mar 06 '19 at 12:20
so you are saving empty array of double ? – Abu Ul Hassan Mar 06 '19 at 12:22
also please show me data dictionary you are saving. – Abu Ul Hassan Mar 06 '19 at 12:23
Well, first I've this. (On my first view, where I save it to Firestore) ``var locations: [CLLocationCoordinate2D] = [] var latitudes:[Double] = [] var longitudes:[Double] = [] ViewDidLoad() { latitudes = locations.map({ $0.latitude }) longitudes = locations.map({ $0.longitude }) } SaveToFireStore() { //A lot of code before this, but nothing that includes lat and long. "latitude": latitudes, "longitude": longitudes ] } `` – Mar 06 '19 at 12:32
check edited answer actually you are accessing data with wrong keys... "latitude" , "longitude" are valid keys but you are retrieving with "Latitude" , "Longitude" which does not exist in your data snapshot . – Abu Ul Hassan Mar 06 '19 at 13:12

Query an array from Firestore

2 Answers2