由于某些原因,解析得到的JSON对象在网络调用和我们构建的api之后不会更新。我检查了端点,现在它会立即更新。我有一个计时器,每10秒调用一次,但解析的json直到大约一分钟后才更新。我试着把它放在主线上,但仍然不起作用。下面是我的代码:
@objc func getLaunches() {
let simulator = UserDefaults.standard.string(forKey: self.launchSimulator)
if(simulator == self.password){
print("they are the same")
}
guard let launchUrl = URL(string: launchesURL) else {
return
}
let request = URLRequest(url: launchUrl)
DispatchQueue.main.async { [weak self] in
let task = URLSession.shared.dataTask(with: request, completionHandler: {
(data, response, error) -> Void in
if let error = error {
print(error)
return
}
// Parse JSON data
if let data = data {
self?.launches.removeAll()
self?.launches = (self!.parseJsonData(data: data))
let nextlaunch = self?.launches[0]
// Reload table view
self?.hours = nextlaunch?.time
self?.yearMonth = nextlaunch?.date
var fulltime = self?.yearMonth
fulltime!.insert("-", at: fulltime!.index(fulltime!.startIndex, offsetBy: 4))
fulltime!.insert("-", at: fulltime!.index(fulltime!.startIndex, offsetBy: 7))
fulltime = fulltime! + " "
fulltime = fulltime! + self!.hours
let fullFormatter = DateFormatter()
fullFormatter.dateFormat = "YYYY-MM-dd HH:mm"
fullFormatter.timeZone = TimeZone(abbreviation: "EST")
self?.launchDate = fullFormatter.date(from: fulltime!)
self?.getCountdown()
}
})
task.resume()
}
}
//parse launch info from json to dictionary into launches object
func parseJsonData(data: Data) -> [NextLaunch] {
var launches = [NextLaunch]()
do {
let jsonResult = try JSONSerialization.jsonObject(with: data, options:
JSONSerialization.ReadingOptions.allowFragments) as? NSDictionary
let jsonLaunches = jsonResult?["launches"] as! [NSDictionary]
for jsonLaunch in jsonLaunches {
let launch = NextLaunch()
launch.date = jsonLaunch["date"] as! String
launch.time = jsonLaunch["time"] as! String
if(launch.time == ""){
launch.time = "00:00"
}
launch.mission = jsonLaunch["mission"] as! String
launch.launchpad = jsonLaunch["launch_pad"] as! String
launch.image = jsonLaunch["image"] as! String
launch.delay = jsonLaunch["delayed"] as! String
//show delay image if it is delayed
if(launch.delay == "1"){
self.delayed()
}else{
self.notDelayed()
}
launches.append(launch)
}
} catch {
print(error)
}
return launches
}发布于 2019-04-06 06:24:05
你需要
DispatchQueue.main.async {
self?.getCountdown()
}因为URLSession.shared.dataTask(with:的响应发生在后台线程中
https://stackoverflow.com/questions/55544001
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