用Swift 3解析JSON
问题描述：
我一直试图让这个工作两个星期。它使用Swift 2在iOS 9上工作，但现在看起来没有任何理由。我添加了print("[DEBUG] I was here 1/2/3/4")来调试代码，打印出的所有代码都是[DEBUG] I was here 1。有任何想法吗？它让我疯狂。用Swift 3解析JSON
func downloadData() {
//clear the arrays
arrayPosts = [String]()
arrayLinks = [String]()
arrayConditions = [String]()
arrayIDs = [String]()
//debug
print("[DEBUG] I was here: 1")
//baseURL is a string with URL to JSON Endpoint
let url = URL(string: baseURL)
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
if error != nil {
print("[ERROR] [DEBUG] Error with connection: \(error)")
} else {
do {
//debug
print("[DEBUG] I was here: 2")
if let json = try JSONSerialization.jsonObject(with: data!, options:[.mutableContainers, .allowFragments]) as? [[String: Any]] {
for item in json {
//debug
print("[DEBUG] I was here: 3")
if let startTime = item["current_time"] as? Int {
if self.defaults.integer(forKey: "startTime") == 0 {
self.defaults.set(startTime, forKey: "startTime")
}
}
if let posts = item["posts"] as? [[String: AnyObject]] {
//debug
print("[DEBUG] I was here: 4")
for post in posts {
if let text = post["text"] as? String {
if let condition = post["conditions"] as? String{
if let url = post["url"] as? String {
if let id = post["id"] as? String {
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
}
}
}
}
}
}
}
}
} catch {
print("[ERROR] [DEBUG] Something went wrong during data download from the server.")
}
}
}).resume()
}
这里的JSON数据，以防万一：
{
"status": "ok",
"num_results": "4",
"current_time": 1474386061,
"user_time": 0,
"posts": [
{
"text": "If your shirt isn't tucked into your pants, then your pants are tucked into your shirt.",
"conditions": "4",
"url": "0",
"time": "0",
"id": "108"
},
{
"text": "Veteran Kills Himself in Parking Lot of V.A. Hospital on Long Island",
"conditions": "6",
"url": "http://www.nytimes.com/2016/08/25/nyregion/veteran-kills-himself-in-parking-lot-of-va-hospital-on-long-island.html",
"time": 1472076000,
"id": "1472076000"
},
{
"text": "Leaked Script Shows What Advisers Want Donald Trump to Say at Black Church",
"conditions": "6",
"url": "http://www.nytimes.com/2016/09/02/us/politics/donald-trump-black-voters-wayne-jackson.html",
"time": 1472767200,
"id": "1472767200"
},
{
"text": "Creepy Clown Sightings in South Carolina Cause a Frenzy",
"conditions": "6",
"url": "http://www.nytimes.com/2016/08/31/us/creepy-clown-sightings-in-south-carolina-cause-a-frenzy.html",
"time": 1472594400,
"id": "1472594400"
}
]
}
答
我已经找到了解决办法。我将代码移到了后台队列中。解决了这个问题。
答
func downloadData() {
//clear the arrays
arrayPosts = [String]()
arrayLinks = [String]()
arrayConditions = [String]()
arrayIDs = [String]()
//debug
print("[DEBUG] I was here: 1")
//baseURL is a string with URL to JSON Endpoint
let url = URL(string: baseURL)
let session = URLSession.shared
let task = session.dataTask(with: url!) { (data:Data?, response:URLResponse?, error:Error?) in
if error != nil {
print("[ERROR] [DEBUG] Error with connection: \(error)")
} else {
do {
//debug
print("[DEBUG] I was here: 2")
if let json = try JSONSerialization.jsonObject(with: data!, options:[.mutableContainers, .allowFragments]) as? [[String: Any]] {
for item in json {
//debug
print("[DEBUG] I was here: 3")
if let startTime = item["current_time"] as? Int {
if self.defaults.integer(forKey: "startTime") == 0 {
self.defaults.set(startTime, forKey: "startTime")
}
}
if let posts = item["posts"] as? [[String: AnyObject]] {
//debug
print("[DEBUG] I was here: 4")
for post in posts {
if let text = post["text"] as? String {
if let condition = post["conditions"] as? String{
if let url = post["url"] as? String {
if let id = post["id"] as? String {
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
}
}
}
}
}
}
}
}
} catch {
print("[ERROR] [DEBUG] Something went wrong during data download from the server.")
}
}
}
task.resume()
}
+0
这似乎并不奏效。它停在“[DEBUG]我又来了1”。 –
答
试试下面的代码：
import UIKit
class ViewController: UIViewController {
var arrayPosts = [String]()
var arrayLinks = [String]()
var arrayConditions = [String]()
var arrayIDs = [String]()
override func viewDidLoad() {
super.viewDidLoad()
self.downloadData()
}
func downloadData()
{
let url = NSURL(string: "http://getmydetails.pe.hu/test/parsejsonswift3.php") //Provided JSON data on my server. i don't know how longer it is present there!.
let request = NSMutableURLRequest(url: url! as URL)
let task = URLSession.shared.dataTask(with: request as URLRequest) { data,response,error in
guard error == nil && data != nil else
{
print("Error:",error)
return
}
let httpStatus = response as? HTTPURLResponse
if httpStatus!.statusCode == 200
{
if data?.count != 0
{
let responseString = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary //because JSON data started with dictionary. Not an array
let status = responseString["status"] as! String
if status == "ok"
{
print("Status is :", status)
let timevar = responseString["current_time"] //not specified as String or Int
print(String(describing: timevar)) // print by converting anyobject to string
if let posts = responseString["posts"] as? [AnyObject] // posts started with array
{
for post in posts
{
let text = post["text"] as! String //specify as String
print(text)
let condition = post["conditions"] as! String
let url = post["url"] as! String
let id = post["id"] as! String
DispatchQueue.main.sync
{
self.arrayPosts.append(text)
self.arrayConditions.append(condition)
self.arrayLinks.append(url)
self.arrayIDs.append(id)
//optional to check
self.afterJSON()
}
}
}
else
{
print("I could not find post array")
}
}
else
{
print("Status is not Okay!")
}
}
else
{
print("No data got from url!")
}
}
else
{
print("error httpstatus code is :",httpStatus!.statusCode)
}
}
task.resume()
}
func afterJSON()
{
print("Posts are:\n\t\t",arrayPosts)
print("Conditions are:\n\t\t",arrayConditions)
print("Links are:\n\t\t",arrayLinks)
print("ID's are:\n\t\t",arrayIDs)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
输出就像下面的截图，
如果你迷惑，然后看到我video是给你的。
如果有任何疑问，请发表评论如下：d
答
感谢的人我按照你的代码中得到的数据））
func getJSON(){
let wUrl = "http://api.fixer.io/latest"
let Url = NSURL(string: wUrl)
let request = NSMutableURLRequest(url: Url! as URL)
let task = URLSession.shared.dataTask(with: request as URLRequest){ data, response, error in
guard error == nil && data != nil else
{
print("Error:", error ?? "some error")
return
}
let httpStatus = response as? HTTPURLResponse
if httpStatus!.statusCode == 200 {
if data?.count != 0 {
let resposeString = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary
let base = resposeString["base"] as? String
print(base ?? "")
let date = resposeString["date"] as? String
print(date ?? "")
let rates = resposeString["rates"] as! Dictionary<String, AnyObject>
for (key, value) in rates{
print("\(key)->\(value)")
}
}
else
{
print("Data is emty")
}
}
else {
print("error httpStatus code: ", httpStatus?.statusCode ?? "")
}
};task.resume()
}
我刚刚用假网址测试，它关系到“[DEBUG]我在这里：2“。 – Moritz
是'let url = URL（string：baseURL）'nil？ – Larme
@EricAya理论上它应该。我再次运行它，以防万一它停在“[DEBUG]我在这里：1”。可能是其他的错误？就像我使用http而不是https一样？ –