如何在pickerview中获取（使用的struct：codable）解析字符串的结果

Question

I have hit the API and got the response successfully. I used codable here for parsing.1.But could not get a particular value. id? 2. The picker is called first and not loaded with the strings which we parsed.

Parsing from codable is littly sticky. How to get the array content inside it , like the id value into it.
codable part: struct Reasons : Codable{ let reason_and_whom_meet : both? }

struct both :Codable{
   let reason_list : [reasonlist]?
   let whom_meet : [nameList]?
}

struct reasonlist :Codable{
  let id: Int?    //This "id" i couldnt access. 
  let reason : String?
  enum CodingKeys: String, CodingKey {

  case reason
  case id
  }
}

struct nameList :Codable{
    let name : String?
    enum CodingKeys: String, CodingKey{
        case name
    }
}

The codable struct I did by the structure of json which i receive. Should I change the structure of the struct I have used.

If you want the json value also I can provide, but the struct is exact hierarchy of json.

Code Part:

do {
    let gotData = try JSONDecoder().decode(Reasons.self, from: data!)
    let persons = gotData.reason_and_whom_meet?.whom_meet

    self.wtmArray.add(persons)
    print(self.wtmArray)

    let reasons = gotData.reason_and_whom_meet?.reason_list
    self.reasonArray.add(reasons)
    print(self.reasonArray)

    let reasonID = gotData.reason_and_whom_meet?.reason_list![self.reasonID]
    print(reasons)
} catch let err {
    print("Error", err)
}

Also the picker delegate methods are called first but the response is empty at that time. How to resolve this? My picker shows empty. And the response are like :

"GoogleClassroomPoC.nameList(name: Optional(\"Teacher\"))"

But I need that Teacher and Principal alone in my array. Should I convert that to any format or can we show it directly in pickerview.

I am fighting with this parsing, Please help!

Answer 1

I have created a simple code that is similar to your scenario on how to get this working.

1. A simple UIPickerView with a single component that display reason of reason_list of both .

var data: both?

@IBOutlet weak var picker: UIPickerView!

override func viewDidLoad()
{
    super.viewDidLoad()
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{
    return self.data?.reason_list?.count ?? 0
}

func numberOfComponents(in pickerView: UIPickerView) -> Int
{
    return 1
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
{
    return self.data?.reason_list?[row].reason
}

Initially, when the ViewController is loaded, data is nil and so the UIPickerView doesn't show anything.

2. I have created a UIButton that loads the data and the UIPickerView is reloaded. I've used some hardcoded data. You can get this data from your API.

@IBAction func loadData(_ sender: UIButton)
{
    let jsonString = """
    {
        "reason_list": [
            {"id": 1, "reason": "ABCD"},
            {"id": 2, "reason": "WXYZ"}
        ]
    }
    """

    if let data = jsonString.data(using: .utf8)
    {
        self.data = try? JSONDecoder().decode(both.self, from: data)
         DispatchQueue.main.async {[weak self] in
               self?.picker.reloadComponent(0) //HERE..!!!
         }
    }
}

Let me know if you still face any issues.