在 PickerView IOS Swift 4.2 中从服务器加载数据

Question

我正在开发 IOS 应用程序，我想在我的 PickerView 中显示来自服务器的数据。我是 Ios 开发的新手，这就是为什么我对如何在我的 PickerView 中加载任何 ParseObject 数据感到困惑。我的 ParseObject 包含 "title" 和 "status" 值。我想在我的 PickerView 中显示来自 ParseObject 的 "title" 的值，所以稍后如果我点击 PickerView 我也可以得到那个 ParseObject。下面给出了我的代码，请指导我如何在我的 PickerView 中显示 ParseObject 数据。

import Foundation
import UIKit
import Parse

class SignUpViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {



    @IBOutlet weak var positionPickerOutlet: UIPickerView!
     var pickerData: [String] = [String]()
     var selectPositionsData: [PFObject] = [PFObject]()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.positionPickerOutlet.delegate = (self as UIPickerViewDelegate)
        self.positionPickerOutlet.dataSource = (self as UIPickerViewDataSource)
        getPositionData()
    }

    @IBAction func cancelFunction(_ sender: Any) {

        dismiss(animated: true, completion: nil)
        print("Sign Up Canceled")

    }

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

        // Row count: rows equals array length.
        return pickerData.count
    }

    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    func pickerView(_ pickerView: UIPickerView,
                    titleForRow row: Int,
                    forComponent component: Int) -> String? {

        // Return a string from the array for this row.
        return pickerData[row]
    }

// 在这里，我调用了一个 ParseQuery 函数并获取了一个 ParseObject 列表并将其放入我的 selectPositionsData 数组中。

    func getPositionData(){

              let parseQuery = PFQuery(className:"UserPosition")
                parseQuery.limit = 100
                parseQuery.order(byAscending: "createdAt")
                parseQuery.whereKey("status", equalTo: true)

        parseQuery.findObjectsInBackground { (objects :[PFObject]?, error: Error?) in
            if objects != nil {
                // do something with the array of object returned by the call
                for parseObject in objects! {
                    self.selectPositionsData.append(parseObject)
// Here I am putting parseObject "title" in my array.

self.pickerData.append(parseObject.value(forKey: "title") as! String)
                    }
                    print(self.selectPositionsData)
                    self.positionPickerOutlet.reloadAllComponents()
                } else {
                    print(error?.localizedDescription as Any)
                }
            }
        }

    }

Answer 1

在您的选择器 View DidSelect 方法中获取如下值：

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
            let title = self.selectPositionsData[row].value(forKey: "title") as! String
            let status = self.selectPositionsData[row].value(forKey: "status") as! String

           let objectAtIndex = self.selectPositionsData[row]
        }

Answer 2

从属于 index/row 的 selectPositionsData[] 获取一个 object 并从 ParseObject 获取它的属性值。无需将字符串从 selectPositionsData[] 迭代到单独的标题数组。

func pickerView(_ pickerView: UIPickerView,
                    titleForRow row: Int,
                    forComponent component: Int) -> String? {

        // Return a string from the array for this row.
        return  selectPositionsData[row].value(forKey: "title")
    }

在 PickerView IOS Swift 4.2 中从服务器加载数据

Load data from server in PickerView IOS Swift 4.2

ios

swift

uipickerview