So I am not sure how to make the quote update ones daily at the same time for all users not depending on the last time they opened the app? If I am not specific enough or anything let me know. Thanks:)
let tasks = URLSession.shared.dataTask(with: URL(string: "https://talaikis.com/api/quotes/random/")!) { (data, response, error) in
if error != nil {
print("error")
} else {
if let content = data {
do {
let Json = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
if let data = Json as? [AnyHashable:Any] {
if let quote = data["quote"], let cat = data["cat"], let author = data["author"] as? String {
print(cat)
DispatchQueue.main.async {
self.myLabel.text = "\(quote)"
self.authorLabel.text = "\(author)"
}
}
}
} catch {
}
}
}
}
tasks.resume()
Related
I'm new to Swift, and I want to 1) run a function that extracts a value from a JSON array (this part works) and 2) pass that variable into another function which will play that URL in my audio player.
My issue: I can't access that string stored in a variable outside the first function. Luckily, there's a bunch of questions on this (example), and they say to establish a global variable outside the function and update it. I have tried this like so:
var audio = ""
override func viewDidLoad() {
super.viewDidLoad()
let url = URL(string: "http://www.example.json")
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
guard let data = data, error == nil else { return }
let json: Any?
do{
json = try JSONSerialization.jsonObject(with: data, options: [])
}
catch{
return
}
guard let data_list = json as? [[String:Any]] else {
return
}
// here's the important part
if let foo = data_list.first(where: {$0["episode"] as? String == "Special Episode Name"}) {
// do something with foo
self.audio = (foo["audio"] as? String)!
} else {
// item could not be found
}
}).resume()
print(audio) // no errors but doesn't return anything
I have confirmed the JSON extraction is working -- if I move that print(audio) inside the function, it returns the value. I just can't use it elsewhere.
I originally tried it without the self. but returned an error.
Is there a better way to store this string in a variable so I can use it in another function?
EDIT: Trying new approach based on Oleg's first answer. This makes sense to me based on how I understand didSet to work, but it's still causing a thread error with the play button elsewhere.
var audiotest = ""{
didSet{
// use audio, start player
if let audioUrl = URL(string: audiotest) {
let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let destinationUrl = documentsDirectoryURL.appendingPathComponent(audioUrl.lastPathComponent)
//let url = Bundle.main.url(forResource: destinationUrl, withExtension: "mp3")!
do {
audioPlayer = try AVAudioPlayer(contentsOf: destinationUrl)
} catch let error {
print(error.localizedDescription)
}
} // end player
}
}
override func viewDidLoad() {
super.viewDidLoad()
let url = URL(string: "http://www.example.com/example.json")
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
guard let data = data, error == nil else { return }
let json: Any?
do{
json = try JSONSerialization.jsonObject(with: data, options: [])
}
catch{
return
}
guard let data_list = json as? [[String:Any]] else {
return
}
if let foo = data_list.first(where: {$0["episode"] as? String == "Houston Preview"}) {
// do something with foo
self.audiotest = (foo["audio"] as? String)!
} else {
// item could not be found
}
print(self.audiotest)
}).resume()
The request for the data is asynchronous so the code that is inside the completionHandler block happens some time later (depending on the server or the timeout) , that’s why if you try to print outside the completionHandler actually the print func happens before you get the data.
There are couple of solution:
1. Add property observer to your audio property and start playing when it is set:
var audio = “”{
didSet{
// use audio, start player
}
}
2. Wrapping the request with a method that one of its parameters is a completion closure:
// the request
func fetchAudio(completion:(String)->()){
// make request and call completion with the string inside the completionHandler block i.e. completion(audio)
}
// Usage
fetchAudio{ audioString in
// dispatch to main queue and use audioString
}
Try this code. No need to take global variable if it is not being used in multiple function. you can return fetched URL in completion handler.
func getAudioUrl(completionHandler:#escaping ((_ url:String?) -> Void)) {
let url = URL(string: "http://www.example.json")
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
guard let data = data, error == nil else { return }
let json: Any?
do{
json = try JSONSerialization.jsonObject(with: data, options: [])
}
catch{
return
}
guard let data_list = json as? [[String:Any]] else {
return
}
// here's the important part
if let foo = data_list.first(where: {$0["episode"] as? String == "Special Episode Name"}) {
// do something with foo
let audio = (foo["audio"] as? String)!
completionHandler(audio)
} else {
// item could not be found
completionHandler(nil)
}
}).resume()
}
func useAudioURL() {
self.getAudioUrl { (url) in
if let strUrl = url {
// perform your dependant operation
print(strUrl)
}else {
//url is nil
}
}
}
Here i had implemented pagination for the table view and items are loaded by using model class but here the loaded items are replacing with the new items and whenever it calls api it returns the new data and old data is overriding on it and displaying only 10 items at a time i am implementing it for first time can anyone help me how to resolve the issue ?
func listCategoryDownloadJsonWithURL(listUrl: String) {
let url = URL(string: listUrl)!
print(listUrl)
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil { print(error!); return }
do {
if let jsonObj = try JSONSerialization.jsonObject(with: data!) as? [String:Any] {
self.listClassModel = ModelClass(dict: jsonObj as [String : AnyObject])
DispatchQueue.main.async {
guard let obj = self.listClassModel else { return }
let itemsCount = obj.items.count
print(itemsCount)
for i in 0..<itemsCount {
let customAttribute = obj.items[i].customAttribute
for j in 0..<customAttribute.count {
if customAttribute[j].attributeCode == "image" {
let baseUrl = "http://192.168.1.11/magento2/pub/media/catalog/product"
self.listCategoryImageArray.append(baseUrl + customAttribute[j].value)
print(self.listCategoryImageArray)
}
}
}
self.activityIndicator.stopAnimating()
self.activityIndicator.hidesWhenStopped = true
self.collectionView.delegate = self
self.collectionView.dataSource = self
self.collectionView.reloadData()
self.collectionView.isHidden = false
self.tableView.reloadData()
}
}
} catch {
print(error)
}
}
task.resume()
}
You are assigning your result data to model array, each time you call your API. This is the reason that your old data is getting replaced with new one. Rather than assigning, you should append the new data to your datasource array.
if let jsonObj = try JSONSerialization.jsonObject(with: data!) as? [String:Any] {
self.listClassModel.append(contentsOf: ModelClass(dict: jsonObj as [String : AnyObject]))
Also make sure you initialize your array as an empty array first. (maybe in declaration or viewDidLoad) before calling API.
I have been trying to get the below code to return an array of information that can use in a UIPickerView class "title for Rows. The code does not work, I do now that when I run the print script it does return a list of all the values from my JSON values. A sample of parsed JSON. I have been watching YouTube Videos and reading info about this for two evenings now. Any help would be great. Everything I find sends Parsed JSON results to a table view.
{
date = "2017-05-01";
"financial_institution" = "Your Neighbourhood C.U.";
"five_year" = "2.79";
"four_year" = "3.15";
key = 86;
"one_year" = "2.79";
"six_months" = 0;
"three_year" = "3.09";
"two_year" = "2.89";
"variable_rate" = 0;
}
)
func getJSONData()
{
let url = URL(string:"")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print("error")
}
else {
if let mydata = data {
do {
let myJson = try JSONSerialization.jsonObject(with: mydata, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
print(myJson)
var lenderName = myJson["financial_institution"]
for i in lenderName {
var lender = "financial_institution"
lender += "\(i)"
var lenderList = myJson[lender].string as String!
lenderNamesArray.append(lenderList)
}
}
catch {
// catch error
}
}
}
}
task.resume()
}
The following functions makes an API call which downloads JSON data and
passes it into an another function imp, which in turn creates the arrays!
func previewer(var spotify_id : [String])
{
var serial_number = 0
for var x in spotify_id
{
let spotify_url = "https://api.spotify.com/v1/tracks/"
let url_with_pars = spotify_url + x
let myurl_1 = NSURL(string: url_with_pars)
let timeout = 15
let request_1 = NSMutableURLRequest(URL: myurl_1!, cachePolicy: .ReloadIgnoringLocalAndRemoteCacheData,
timeoutInterval: 15.0)
let queue = NSOperationQueue()
request_1.HTTPMethod = "GET"
let task = NSURLSession.sharedSession().dataTaskWithRequest(request_1, completionHandler: { (data, response, error) in
//NSURLConnection.sendAsynchronousRequest(request_1, queue: queue, completionHandler: { (reponse, data, error) in
if error != nil
{
print("Error!")
}
else
{
do
{
if let data_1 = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary
{
self.imp(data_1)
}
else
{
print("error!")
}
}
catch
{
print("error")
}
}
})
//task.resume()
}
print(artist.count)
do_table_refresh()
}
func do_table_refresh()
{
dispatch_async(dispatch_get_main_queue(), {
self.tableView.reloadData()
return
})
}
//FUNCTION WHICH CREATES ARRAY
func imp(var data_1:NSDictionary)
{
if let artist_name = data_1["artists"]![0]["name"] as? String
{
artist.append(artist_name)
}
else
{
print("artist error")
}
if let song_name = data_1["name"] as? String
{
print(song_name)
songs.append(song_name)
}
else
{
print("song error")
}
if let url = data_1["preview_url"] as? String
{
if let url_1 = data_1["id"] as? String
{
url_list.append([url, url_1])
}
else
{
print("url error")
}
}
else
{
var url_2 = data_1["id"] as? String
url_list.append(["null", url_2!])
}
}
Where exactly would you deal with the asynchronous problem any suggestion?
You should note that all the API calls are asynchronous. You are doing a loop of these so, according to your code, you could have several API calls all happening simultaneously.
// Put this outside the loop
let spotify_url = "https://api.spotify.com/v1/tracks/"
for x in spotify_id {
let url_with_pars = spotify_url + x
// Be careful. The following could be nil
let myurl_1 = NSURL(string: url_with_pars)
// Watch out for ! in the following statement.
let request_1 = NSMutableURLRequest(URL: myurl_1!, cachePolicy: .ReloadIgnoringLocalAndRemoteCacheData,
timeoutInterval: 15.0)
let task = NSURLSession.sharedSession().dataTaskWithRequest(request_1, completionHandler: { (data, response, error) in
// handle data here
// refresh table here.
})
task.resume()
}
// When your code gets here, the data may not have come back yet.
// The following WILL NOT WORK
print(artist.count) // Remove me
do_table_refresh() // Remove me
Here's the problem with this approach. The table will be refreshed each time one of the API calls comes back. If you had 10 API calls, that would be 10 refreshes.
Is there a reason you use NSDictionary? Parsing JSON returns [AnyObject] which you can cast as needed.
I've written a function that should return a value but the value comes from a closure. The problem is if I try to return a value from inside the closure it treats this as being the return value from the completion handler.
private func loadData() throws -> [Item] {
var items = [Item]()
let jsonUrl = "http://api.openweathermap.org/data/2.5/forecast/daily?units=metric&cnt=7&q=coventry,uk"
print(jsonUrl)
let session = NSURLSession.sharedSession()
guard let shotsUrl = NSURL(string: jsonUrl) else {
throw JSONError.InvalidURL(jsonUrl)
}
session.dataTaskWithURL(shotsUrl, completionHandler: {(data, response, error) -> Void in
do {
let json = try NSJSONSerialization.JSONObjectWithData(data!, options: [])
print(json)
guard let days:[AnyObject] = (json["list"] as! [AnyObject]) else {
throw JSONError.InvalidArray
}
for day in days {
guard let timestamp:Double = day["dt"] as? Double else {
throw JSONError.InvalidKey("dt")
}
print(timestamp)
let date = NSDate(timeIntervalSince1970: NSTimeInterval(timestamp))
guard let weather:[AnyObject] = day["weather"] as? [AnyObject] else {
throw JSONError.InvalidArray
}
guard let desc:String = weather[0]["description"] as? String else {
throw JSONError.InvalidKey("description")
}
guard let icon:String = weather[0]["icon"] as? String else {
throw JSONError.InvalidKey("icon")
}
guard let url = NSURL(string: "http://openweathermap.org/img/w/\(icon).png") else {
throw JSONError.InvalidURL("http://openweathermap.org/img/w/\(icon).png")
}
guard let data = NSData(contentsOfURL: url) else {
throw JSONError.InvalidData
}
guard let image = UIImage(data: data) else {
throw JSONError.InvalidImage
}
guard let temp:AnyObject = day["temp"] else {
throw JSONError.InvalidKey("temp")
}
guard let max:Float = temp["max"] as? Float else {
throw JSONError.InvalidKey("max")
}
let newDay = Item(date: date, description: desc, maxTemp: max, icon: image)
print(newDay)
items.append(newDay)
}
return items // this line fails because I'm in the closure. I want this to be the value returned by the loadData() function.
} catch {
print("Fetch failed: \((error as NSError).localizedDescription)")
}
})
}
Add a completion handler (named dataHandler in my example) to your loadData function:
private func loadData(dataHandler: ([Item])->()) throws {
var items = [Item]()
let jsonUrl = "http://api.openweathermap.org/data/2.5/forecast/daily?units=metric&cnt=7&q=coventry,uk"
print(jsonUrl)
let session = NSURLSession.sharedSession()
guard let shotsUrl = NSURL(string: jsonUrl) else {
throw JSONError.InvalidURL(jsonUrl)
}
session.dataTaskWithURL(shotsUrl, completionHandler: {(data, response, error) -> Void in
do {
let json = try NSJSONSerialization.JSONObjectWithData(data!, options: [])
print(json)
guard let days:[AnyObject] = (json["list"] as! [AnyObject]) else {
throw JSONError.InvalidArray
}
for day in days {
guard let timestamp:Double = day["dt"] as? Double else {
throw JSONError.InvalidKey("dt")
}
print(timestamp)
let date = NSDate(timeIntervalSince1970: NSTimeInterval(timestamp))
guard let weather:[AnyObject] = day["weather"] as? [AnyObject] else {
throw JSONError.InvalidArray
}
guard let desc:String = weather[0]["description"] as? String else {
throw JSONError.InvalidKey("description")
}
guard let icon:String = weather[0]["icon"] as? String else {
throw JSONError.InvalidKey("icon")
}
guard let url = NSURL(string: "http://openweathermap.org/img/w/\(icon).png") else {
throw JSONError.InvalidURL("http://openweathermap.org/img/w/\(icon).png")
}
guard let data = NSData(contentsOfURL: url) else {
throw JSONError.InvalidData
}
guard let image = UIImage(data: data) else {
throw JSONError.InvalidImage
}
guard let temp:AnyObject = day["temp"] else {
throw JSONError.InvalidKey("temp")
}
guard let max:Float = temp["max"] as? Float else {
throw JSONError.InvalidKey("max")
}
let newDay = Item(date: date, description: desc, maxTemp: max, icon: image)
print(newDay)
items.append(newDay)
}
dataHandler(items)
} catch {
print("Fetch failed: \((error as NSError).localizedDescription)")
}
}).resume()
}
do {
try loadData { itemsArray in
print(itemsArray)
}
} catch {
print(error)
}
I've tested it in a Playground and it works without errors: