When I run the application Xcode told me that
unexpectedly found nil while unwrapping an Optional value
at the url but the url isn't nil, can someone help?
here is the code
import Foundation
protocol WeatherUndergroundServiceByGeographicalDelegate{
func setWeatherByGeographical(weather:WeatherUnderground)
}
class WeatherUndergoundServiceByGeographical{
var delegate:WeatherUndergroundServiceByGeographicalDelegate?
func getWeatherFromWeatherUnderground(latitude:Double, longitude:Double){
let path = "http://api.wunderground.com/api/48675fd2f5485cff/conditions/geolookup/q/\(latitude,longitude).json"
let url = NSURL(string: path)
//session
let session = NSURLSession.sharedSession()
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Error is at here~~~~~~~~~~~~~~~~~~~~~~~~~
let task = session.dataTaskWithURL(url!) { (data:NSData?, response:NSURLResponse?, error:NSError?) -> Void in
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
let json = JSON(data: data!)
//parsing json weather condition from weather api. using swiftyJson
let name = json["current_observation"]["display_location"]["city"].string
let temp = json["current_observation"]["temp_c"].double
let windsp = json["current_observation"]["wind_mph"].double
//prasing the weather data
let weather = WeatherUnderground(cityName: name!, temperature: temp!, windSpeed: windsp!)
if self.delegate != nil{
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.delegate?.setWeatherByGeographical(weather)
})
}
}
task.resume()
}
}
You probably have error in your path string, try this:
let path = "http://api.wunderground.com/api/48675fd2f5485cff/conditions/geolookup/q/\(latitude),\(longitude).json"
The reason is that you are interpolating tuple value \(latitude,longitude) in the string, which adds extra space and makes url string invalid because space is not percent-escaped.
Instead you have to interpolate each value with a comma between them: \(latitude),\(longitude)
let path = "http://api.wunderground.com/api/48675fd2f5485cff/conditions/geolookup/q/\(latitude,longitude).json"
I think you mean:
let path = "http://api.wunderground.com/api/48675fd2f5485cff/conditions/geolookup/q/\(latitude),\(longitude).json"
Related
Essentially I am parsing JSON data and assigning it to a variable called addressPressNow I then have the following function that executes when a user taps on a UILabel:
The goal is to have Apple Maps open provided the variable value it contains.
Because I am assigning an address to a variable it will contain spaces
ex: 3981 Test Drive Cupertino CA 95014
NOTE: The value of the variable is being passed correctly because when I do print(addressPressNow) in func tapFunction it prints correctly.
#objc
func tapFunction(sender:UITapGestureRecognizer) {
let targetURL = NSURL(string: "http://maps.apple.com/?q=" + addressPressNow)!
UIApplication.shared.openURL(targetURL as URL)
}
The issue is I am having trouble applying the variable to the string URL with the following error:
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an
Optional value
The following is how I am assigning the value to the variable:
struct FacilityInfo: Decodable {
let address: String
class infoViewController: UIViewController {
var addressPressNow : String = ""
override func viewDidLoad() {
super.viewDidLoad()
let tap = UITapGestureRecognizer(target: self, action: #selector(infoViewController.tapFunction))
addressInfo.isUserInteractionEnabled = true
addressInfo.addGestureRecognizer(tap)
let url = URL(string: "https://test/test/example”)!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
// ensure there is no error for this HTTP response
guard error == nil else {
print ("error: \(error!)")
return
}
// ensure there is data returned from this HTTP response
guard let data = data else {
print("No data")
return
}
// Parse JSON into array of Car struct using JSONDecoder
guard let cars = try? JSONDecoder().decode([FacilityInfo].self, from: data), let secondCar = cars.first
else {
print("Error: Couldn't decode data into cars array")
return
}
DispatchQueue.main.async {
self.addressPressNow = secondCar.facility_address
}
}
"I am assigning an address to a variable it will contain spaces"
If the address contains spaces then creating NSURL with the string will crash. You can use addingPercentEncoding to solve the problem
if let encodedAddress = addressPressNow.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) {
let targetURL = NSURL(string: "http://maps.apple.com/?q=" + encodedAddress)!
UIApplication.shared.openURL(targetURL as URL)
}
And don't use NSURL and force unwrapping. Update it like this
if let encodedAddress = addressPressNow.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed),
let targetURL = URL(string: "http://maps.apple.com/?q=" + encodedAddress) {
UIApplication.shared.openURL(targetURL)
}
As suggested by matt use URLComponents
let addressPressNow = "3981 Test Drive Cupertino CA 95014"
var components = URLComponents(string: "http://maps.apple.com")
components?.queryItems = [URLQueryItem(name: "q", value: addressPressNow)]
print(components?.url)//http://maps.apple.com?q=3981%20Test%20Drive%20Cupertino%20CA%2095014
if let targetURL = components?.url {
UIApplication.shared.open(targetURL, options: [:], completionHandler: nil)
}
You are saying
NSURL(string: "http://maps.apple.com/?q=" + addressPressNow)!
Notice the exclamation mark at the end. That means "if there's a problem, crash me". You can hardly complain if you do in fact crash; that is what you asked to do.
Basically, never use NSURL(string:) if you can avoid it. To form a valid URL, build it up using URLComponents. And form it out of valid components. (It is impossible to say whether facility_address is a valid URL query, because you have not shown what it is.)
Example:
var comp = URLComponents()
comp.scheme = "https"
comp.host = "maps.apple.com"
comp.queryItems = [URLQueryItem(name: "q", value: "1 Infinite Loop, Cupertino, CA")]
if let url = comp.url {
print(url) // https://maps.apple.com?q=1%20Infinite%20Loop,%20Cupertino,%20CA
}
That gives us a valid URL that actually works.
I'd like to use readStringFromURL method to obtain a file from a plist and then use it on insertDataInArrayFromPlist in order to display it or put it on CoreData, substituting let path = Bundle.main.path(forResource: plistFileName, ofType: plistFileExtension).
the ISSUE the try statement gives me this ERROR
Argument labels '(contentsOfURL:, usedEncoding:)' do not match any available overloads
in my viewDidLoad:
let obtainedfile = readStringFromURL(stringURL: kremoteSamplePlist)
print(obtainedfile ?? "nothing to print")
I retrive the file from web
func readStringFromURL(stringURL:String)-> String!{
if let url = NSURL(string: stringURL) {
do {
return try String(contentsOfURL: url, usedEncoding: nil)
} catch {
print("Cannot load contents")
return nil
}
} else {
print("String was not a URL")
return nil
}
}
then I put the data in a struct
func insertDataInArrayFromPlist(arrayOfEntities: inout [product]) {
let path = Bundle.main.path(forResource: plistFileName, ofType: plistFileExtension)
let localArray = NSArray(contentsOfFile: path!)!
for dict in localArray {
var futureEntity = product()
let bdict = dict as! [String: AnyObject]
futureEntity.name = bdict["Name"] as? String
futureEntity.ProductId = bdict["Product Id"] as? String
arrayOfEntities.append(futureEntity)
}
for element in arrayOfEntities {
print("name is \(element.name!), the id is \(element.ProductId!)")
}
}
Theres a library available via Cocoapods, CSV.swift by Yaslab. Allows you to import a csv directly in Swift code and convert to a data type of your own. Does the job for me.
https://github.com/yaslab/CSV.swift
let imgURL:NSURL = NSURL(string: "\(ImageName)")!
at the above line,i'm getting fatal error
fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
Code :
let ImageName = obj["image"] as! String
let imgURL:NSURL = NSURL(string: "\(ImageName)")!
let request: NSURLRequest = NSURLRequest(URL: imgURL)
let session = NSURLSession.sharedSession()
let Imgtask = session.dataTaskWithRequest(request){
(data, response, error) -> Void in
if (error == nil && data != nil)
{
func display_image()
{
pointAnnoation.DisplayImage = UIImage(data: data!)
}
dispatch_async(dispatch_get_main_queue(), display_image)
}
}
Imgtask.resume()
From the above code im trying to store my image from database in annotation
if i printed the 'ImageName' it returns the name from the database correctly, but unable to retain the image
it resulting in the error while running.
You say that
if i printed the 'ImageName' it returns the name from the database correctly
Then that must mean that the ImageName is not valid for a URL
If you look at the description of NSURL(string:) it says:
The URL string with which to initialize the NSURL object. This URL string must conform to URL format as described in RFC 2396, and must not be nil. This method parses URLString according to RFCs 1738 and 1808.
So the question is...how does ImageName look? And can you create a URL from it?
Apart from that, it is always a good idea to use ? instead of ! as #PhillipMills says
Update: I can see that you have posted an example of your URL now. If I do this in a playground:
let url = NSURL(string: " goo.gl/pBmA0d")
I get nil in return, so it would seem that short URLs and NSURLaren't the best of friends.
Update 2: hmm, guess I spoke to quickly, if you look at the above you can see that I have a space before the goo.gl part, if I change that to:
let url = NSURL(string: "goo.gl/pBmA0d")
it actually works, I get a NSURL object.
But another thing I stumbled upon in your code. You declare ImageName as a String here:
let ImageName = obj["image"] as! String
So you don't have to wrap it in \() later on
let imgURL:NSURL = NSURL(string: "\(ImageName)")!
You could simply say:
let imageURL = NSURL(string: ImageName)
And then...as others has said, it is always a good idea to use ? instead of !
So you could write:
if let imageName = obj["image"] as? String,
let imageURL = NSURL(string: imageName) {
//we're in business :-)
}
and be safe and sound
Try to use guard or if let for helping yourself.
let ImageName = obj["image"] as! String
if let imgURL = NSURL(string: ImageName) {
let request: NSURLRequest = NSURLRequest(URL: imgURL)
let session = NSURLSession.sharedSession()
let Imgtask = session.dataTaskWithRequest(request){ (data, response, error) -> Void in
if (error == nil && data != nil)
{
// What's that func??
func display_image()
{
pointAnnoation.DisplayImage = UIImage(data: data!)
}
dispatch_async(dispatch_get_main_queue(), display_image)
}
}
}
Imgtask.resume()
Don't make force unwrap...use if let to avoid crash ...
if let img = obj["image"] as? String,
imgURL = NSURL(string: img) {
// ... continue with your code ...
}
Please try the following code:
//ImageName is a String type.
guard let ImageName = obj["image"] as? String , let imgURL = NSURL(string: ImageName) else{
return
}
let request: NSURLRequest = NSURLRequest(URL:imgURL)
let session = NSURLSession.sharedSession()
let Imgtask = session.dataTaskWithRequest(request){
(data, response, error) -> Void in
if (error == nil && data != nil)
{
func display_image()
{
pointAnnoation.DisplayImage = UIImage(data: data!)
}
dispatch_async(dispatch_get_main_queue(), display_image)
}
Imgtask.resume()
I try to parse json with SwiftyJSON. One of the fields have url to image and i try to save it as NSData but I face crash and console errors. Crash appears when compiler comes to object creation
code it the following
var JSONStorage : [Article?]?
var objects = [Article?]()
override func viewDidLoad() {
super.viewDidLoad()
let number = arc4random_uniform(1000)
let urlString = "http://wirehead.ru/article.json?\(number)"
if let url = NSURL(string: urlString) {
if let data = try? NSData(contentsOfURL: url, options: []) {
let json = JSON(data: data)
for element in json["article"].arrayValue {
let id = Int(element["id"].stringValue)
let title = element["title"].stringValue
let subtitle = element["subtitle"].stringValue
let body = element["body"].stringValue
let img = element["images"]["main"].rawValue
let obj:Article = Article(id: id!, title: title, subtitle: subtitle, body: body, mainImage: img as! NSData)
objects.append(obj)
print("We are inside if let")
}
}
}
print(objects)
}
Link to JSON is http://wirehead.ru/article.json and here is with highlight http://pastebin.com/AAEFjsQN
Error that I get is
Any advice ?
["images"]["main"] contains an URL represented by a String
To get the image data, use something like this
let imgURLString = element["images"]["main"].stringValue
if let url = NSURL(string:imgURLString) {
let img = NSData(contentsOfURL:url)
}
I'm hoping someone an help me figure out a problem that has me scratching my brain! When I attempt this function using a NSData(contentsOfUrl... structure, this all works fine. However, I am attempting to use a NSURLSession for use on an Apple Watch app, and keep hitting an error;
...
class func fetchData() -> [Complication] {
var task: NSURLSessionDataTask?
let myURL = "http://www.myurl.com/sample.json"
let dataURL = NSURL(string: myURL)
let conf = NSURLSessionConfiguration.defaultSessionConfiguration()
conf.requestCachePolicy = NSURLRequestCachePolicy.ReloadIgnoringCacheData
let session = NSURLSession(configuration: conf)
task = session.dataTaskWithURL(dataURL!) { (data, res, error) -> Void in
if let e = error {
print("dataTaskWithURL fail: \(e.debugDescription)")
return
}
var dataSet = [Complication]()
do {
let json = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as! NSArray
for item in json {
let name: String? = item["name"] as? String
let percent: Int? = item["percent"] as? Int
let timeFromNow: Int? = item["timeFromNow"] as? Int
let myData = Complication(
name: name!,
percent: percent!,
timeFromNow: timeFromNow!
)
dataSet.append(myData)
}
} catch {
print(error)
}
}
return dataSet
//THIS LINE THROWS THE ERROR
}
...
When attempting to return my dataSet array, I receive the error Instance member 'dataSet' cannot be used on type 'Complication'. As mentioned, however, this does seem to work if I were to use a NSData(contentsOfUrl... instead of a NSURLSession, which is where I am stuck!
The data task is a closure that is executed asynchronously. Its return statements returns from the closure, not from the outer function.
Since the closure is executed asynchronously it makes no sense to return data from it: the return type is Void.
You should organize your code differently, e.g. using a completion handler.
Hint: search for "swift return closure" in SO. You will find plenty of questions similar to yours and a number of good answers and suggestions.