ios - Picker不会从正在从Firebase中拉出的数组中获取数据

我在这里有2个选择器，图片的值分配给了从Firebase提取的数据。将其分配给数组，然后将这些值分配给选择器。这是行不通的，我不确定为什么。
这是我的代码：

import UIKit
import Firebase
import FirebaseDatabase
class SearchSelectVC: UIViewController, UIPickerViewDelegate , UIPickerViewDataSource{

    @IBOutlet weak var locationPicker: UIPickerView!
    @IBOutlet weak var datePicker: UIPickerView!
    @IBOutlet weak var locationLB: UILabel!
    @IBOutlet weak var dateLB: UILabel!

    var locData: [String] = [String]()
    var dateData : [String] = [String]()

    override func viewDidLoad() {
        super.viewDidLoad()
        initPickers()
        getLoc(onCompletion: { (data) in
            print(data)
            self.locData = (data)
            print(self.locData)
       })
    }


    func getDate(onCompletion: @escaping ([String]) -> ()) {
        var data : [String] = []
        let selectedLoc = locationLB.text
        var dateRef: DatabaseReference!
        dateRef = Database.database().reference().child("launch").child((selectedLoc)!)
        dateRef.observe(.value) { (snapshot) in
            for child in snapshot.children {
                let snap = child as! DataSnapshot
                let key = snap.key
                data.append(key)
                print("date = \(key)")
                //print(data)

            }
            onCompletion(data)
        }
    }
    func getLoc(onCompletion: @escaping ([String]) -> Void){
        print("here3")
        var data : [String] = []
        var locRef: DatabaseReference!
        locRef = Database.database().reference()
        print("here4")
        locRef.child("launch").observe(.value) { snapshot in
            for child in snapshot.children {
                let snap = child as! DataSnapshot
                let key = snap.key
                data.append(key)
                print("location = \(key)")
                //print(data)


            }
            onCompletion(data)
        }

    }
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        if(pickerView == locationPicker){
            return 1
        }
        else if(pickerView == datePicker){
            return 1
        }
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        if (pickerView == locationPicker) {

            return locData.count
        }
        else if (pickerView == datePicker) {

            return dateData.count
        }
        return 1
    }
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if (pickerView == locationPicker) {
            return locData[row]
        }
        else if(pickerView == datePicker){
            return dateData[row]
        }
        return "thisisbad"
    }
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
    {
        if(pickerView == locationPicker){
            updateLabelLoc()
            getDate(onCompletion: { (data) in
                print(data)
                self.dateData = data
            })
        }
        else if(pickerView == datePicker){
            updateLabelDate()
        }
    }
    func updateLabelLoc(){
        let location = locData[locationPicker.selectedRow(inComponent: 0)]
        locationLB.text = location
    }
    func updateLabelDate(){
        let date = dateData[datePicker.selectedRow(inComponent: 0)]
        dateLB.text = date
    }
    func initPickers(){
        locationPicker.delegate = self
        locationPicker.dataSource = self
        datePicker.delegate = self
        datePicker.dataSource = self
    }

}

数据位于完成处理程序中，并且在完成后，它将正确地从数据库返回数据。选择器显示其中没有任何数据。
谢谢！

最佳答案

创建：

func updatePickers() {
   locationPicker.reloadAllComponents()
   datePicker.reloadAllComponents()
}

在print(self.locData)（在getLoc(onCompletion:)（在viewDidLoad（）中）之后，放入：

self.updatePickers()

关于ios - Picker不会从正在从Firebase中拉出的数组中获取数据，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46677010/