我在Swift中遇到数组问题。
如果我在print(self.days.count)
方法中有initialization
,我总是在数组中获得正确数量的对象days
。但是,如果我在print(self.days.count)
内使用viewDidLoad()
,我总是得到0.有没有办法可以修复它?我感谢任何帮助。
import UIKit
class ViewController: UIViewController, UITableViewDelegate{
//object array for weather
var objectArray = [WeaObject]()
var days = [List]()
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
initialization {
print("succ")
print(self.days.count)
}
tableView.delegate = self
tableView.delegate = self
print(days.count)
//print(objectArray.count)
}
func initialization(completed:@escaping () -> ()){
let jsonUrlString="http://api.openweathermap.org/data/2.5/forecast?zip=22003&appid=c632597b1892b4d415c64ca0e9fca1f1"
guard let url = URL(string: jsonUrlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else { return }
do {
let downloadDays = try JSONDecoder().decode(TestingClass.self, from: data)
self.days = downloadDays.list
DispatchQueue.main.async {
completed()
}
} catch let jsonErr {
print("Error serializing json:", jsonErr)
}
}.resume()
}
}
答案 0 :(得分:1)
您需要在reloadData()
完成区内的表格视图上致电initialization
。
更新viewDidLoad
:
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.delegate = self
initialization {
print("succ")
print(self.days.count)
tableView.reloadData()
}
// Do not print days.count here because days isn't updated yet
}
最好更新主队列上的数据模型:
func initialization(completed:@escaping () -> ()){
let jsonUrlString="http://api.openweathermap.org/data/2.5/forecast?zip=22003&appid=c632597b1892b4d415c64ca0e9fca1f1"
guard let url = URL(string: jsonUrlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else { return }
do {
let downloadDays = try JSONDecoder().decode(TestingClass.self, from: data)
DispatchQueue.main.async {
self.days = downloadDays.list
completed()
}
} catch let jsonErr {
print("Error serializing json:", jsonErr)
}
}.resume()
}
您还应该遵守UITableViewDataSource
:
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSoure {