[英]How to get an indexPath of selected row Swift4 JSON
我正在嘗試使詳細視圖中的標簽充滿來自此示例JSON https://api.myjson.com/bins/18qzq5
的信息,我能夠填充tableView,但是無法獲取該行的indexPath和在detailView中,我收到一個錯誤“在展開一個可選值時意外發現nil”。 我在下面列出的代碼:*順便說一句,我正在使用swift解碼器
[
{
"name": "New York",
"state": "New York",
"detail": "The largest city in the US"
},
{
"name": "Los Angeles",
"state": "California",
"detail": "Second largest city in the US"
}
]
tableView的ViewController
import UIKit
struct City: Codable {
let name: String?
let state: String?
let detail: String?
}
class TableVC: UIViewController {
var citiesList: [City] = []
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
let jsonString = "https://api.myjson.com/bins/18qzq5"
guard let url = URL(string: jsonString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else {return}
do {
let cities = try JSONDecoder().decode([City].self, from: data)
if cities != nil {
self.citiesList = cities
}else{
print("it's nil")
}
print(self.citiesList)
DispatchQueue.main.async {
self.tableView.reloadData()
}
} catch let jsonErr{
print("error serializing json:", jsonErr)
}
}.resume()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let detailVC = segue.destination as? DetailTaskVC
let city = sender as AnyObject as? City
detailVC?.city = city
}
}
extension TableVC: UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return citiesList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell()
cell.textLabel?.text = citiesList[indexPath.row].name
return cell
}
}
extension TableVC: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "toDetail", sender: citiesList[indexPath.row])
}
}
DetailViewController
import UIKit
class DetailTaskVC: UIViewController {
@IBOutlet weak var nameLabel: UILabel!
@IBOutlet weak var stateLabel: UILabel!
@IBOutlet weak var detailLabel: UILabel!
var city: City!
override func viewDidLoad() {
super.viewDidLoad()
self.nameLabel?.text = city.name //Unexpectedly found nil while unwrapping an Optional value
self.stateLabel?.text = city.state
self.detailLabel?.text = city.detail
}
}
希望你們可以幫我解決這個問題,或者在線上有一個教程,你們可以指出我的觀點,因為我搜索了很多內容,但沒有取得積極的結果。
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let detailVC = segue.destination as? DetailTaskVC
let city = sender as AnyObject as? City
detailVC?.city = city
}
將sender as? City
sender as? City
而不是sender as AnyObject as? City
sender as AnyObject as? City
。 您不能將結構轉換為AnyObject。
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