我有一个代码从twitter获取JSON并将其放入名为feedStruct
的结构中,但也将其解析为UITableViewController。
我已经在模拟器中多次测试了它,但也想在我的iPhone上测试它,然后它在这段代码中崩溃了。我在“使应用程序崩溃”的行旁边发表了评论:
线程8:致命错误:在解包可选值时意外发现nil
(我认为在某些时候,线程6也认为,如果这与它有任何关系。)
以下是代码:
import Foundation
protocol twitterModelProtocol: class {
func twitterDownloaded(items: [Any])
func feedTwitterDatesDownloaded(items: [feedStruct])
}
class twitterModel: NSObject {
//properties
weak var delegate: twitterModelProtocol!
let urlPath = "http://MYWEBPAGE/twit.php" //this will be changed to the path where service.php lives
func downloadTwitterItems() {
let url: URL = URL(string: urlPath)!
let defaultSession = Foundation.URLSession(configuration: URLSessionConfiguration.default)
let task = defaultSession.dataTask(with: url) { (data, response, error) in
if error != nil {
print("Failed to download twitter data")
} else {
print("Twitter data downloaded")
self.parseTwitterJSON(data!)
}
}
task.resume()
}
func parseTwitterJSON(_ data:Data) {
var jsonResult = [Any]()
do{
jsonResult = try JSONSerialization.jsonObject(with: data, options:JSONSerialization.ReadingOptions.allowFragments) as! [Any]
} catch let error as NSError {
print(error)
}
var jsonElement = NSDictionary()
var feeds = [feedStruct]()
for i in 0 ..< jsonResult.count {
jsonElement = jsonResult[i] as! NSDictionary
let feed = feedStruct()
//the following insures none of the JsonElement values are nil through optional binding
if let unixstamp = jsonElement["created_at"] as? String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "EEE MMM d HH:mm:ss Z yyyy"
print(unixstamp)
let date = dateFormatter.date(from: unixstamp)! //THIS LINE IS MAKING THE APP CRASH ON iPHONE NOT SIMULATOR <<<<<<<<<<<<<<<<<<<<<
let calendar = Calendar.current
let components = calendar.dateComponents([.year, .month, .day, .hour], from: date)
let finalDate = calendar.date(from:components)
let timestamp = finalDate?.timeIntervalSince1970
let finalTimestamp = String(format: "%.0f", timestamp!)
feed.date = finalTimestamp
feed.type = "twitter"
}
feeds.append(feed)
}
DispatchQueue.main.async(execute: { () -> Void in
self.delegate.twitterDownloaded(items: jsonResult)
self.delegate.feedTwitterDatesDownloaded(items: feeds)
})
}
}
答案 0 :(得分:1)
尝试设置以下内容(设备的日期/时间设置可能会导致模拟器和设备之间出现差异):
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "EEE MMM d HH:mm:ss Z yyyy"
dateFormatter.timeZone = TimeZone(identifier: "GMT")
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
guard let date = dateFormatter.date(from: unixstamp) else {
// deal with non-existent date
}