So im a bit new to swift and object-c as well and was wondering if someone could help me out a bit.
I'm used to creating usually a utils file where I have functions I use often in programming.
In this case im trying to call a function from another swift file and return an array of data.
For example in my mainViewController.swift im calling the function:
var Data = fbGraphCall()
In the Utils.swift file I have a function that Im trying to get it to return an array of data collected.
func fbGraphCall() -> Array<String>{
var fbData: [String] = [""]
if (FBSDKAccessToken.currentAccessToken() != nil){
// get fb info
var userProfileRequestParams = [ "fields" : "id, name, email, about, age_range, address, gender, timezone"]
let userProfileRequest = FBSDKGraphRequest(graphPath: "me", parameters: userProfileRequestParams)
let graphConnection = FBSDKGraphRequestConnection()
graphConnection.addRequest(userProfileRequest, completionHandler: { (connection: FBSDKGraphRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
if(error != nil) {
println(error)
} else {
// DEBUG
println(result)
let fbEmail = result.objectForKey("email") as! String
// DEBUG
println(fbEmail)
fbData.append("\(fbEmail)")
let fbID = result.objectForKey("id") as! String
if(fbEmail != "") {
PFUser.currentUser()?.username = fbEmail
PFUser.currentUser()?.saveEventually(nil)
}
println("Email: \(fbEmail)")
println("FBUserId: \(fbID)")
}
})
graphConnection.start()
}
println(fbData)
return fbData
}
I can confirm that im getting the fbEmail and fbID back from facebook with my debug statements but as I said im still new on how to return data back.
Ideally I usually want an array back if its more than one value or the ability to get back data like Data.fbEmail, Data.fbID or an array maybe like ["email" : "email#gmail.com", "id" : "1324134124zadfa"]
When I hit the return statement its blank.. so not sure why the constants are not keeping values or passing values into my fbData array.. I'm trying fbData.append(fbEmail) for example ..
any thoughts on what might be wrong?
The graphConnection.addRequest is an asynchronous function and you are trying to synchronously return the array of strings back. This won't work because the graphConnection.addRequest is done in the background to avoid blocking the main thread. So instead of returning the data directly make a completion handler. Your function would then become this:
func fbGraphCall(completion: ([String]) -> Void, errorHandler errorHandler: ((NSError) -> Void)?) {
if (FBSDKAccessToken.currentAccessToken() != nil) {
// get fb info
var userProfileRequestParams = [ "fields" : "id, name, email, about, age_range, address, gender, timezone"]
let userProfileRequest = FBSDKGraphRequest(graphPath: "me", parameters: userProfileRequestParams)
let graphConnection = FBSDKGraphRequestConnection()
graphConnection.addRequest(userProfileRequest, completionHandler: { (connection: FBSDKGraphRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
if(error != nil) {
println(error)
errorHandler?(error!)
} else {
var fbData = [String]() // Notice how I removed the empty string you were putting in here.
// DEBUG
println(result)
let fbEmail = result.objectForKey("email") as! String
// DEBUG
println(fbEmail)
fbData.append("\(fbEmail)")
let fbID = result.objectForKey("id") as! String
if(fbEmail != "") {
PFUser.currentUser()?.username = fbEmail
PFUser.currentUser()?.saveEventually(nil)
}
println("Email: \(fbEmail)")
println("FBUserId: \(fbID)")
completion(fbData)
}
})
graphConnection.start()
}
}
I added the completion handler and the error handler blocks that get executed according to what's needed.
Now at the call site you can do something like this:
fbGraphCall( { println($0) // $0 refers to the array of Strings retrieved }, errorHandler: { println($0) // TODO: Error handling }) // Optionally you can pass `nil` for the error block too incase you don't want to do any error handling but this is not recommended.
Edit:
In order to use the variables you would do something like this at the call site
fbGraphCall( { array in
dispatch_async(dispatch_get_main_queue(), { // Get the main queue because UI updates must always happen on the main queue.
self.fbIDLabel.text = array.first // array is the array we received from the function so make sure you check the bounds and use the right index to get the right values.
self.fbEmailLabel.text = array.last
})
}, errorHandler: {
println($0)
// TODO: Error handling
})
Related
I need to cast the below response from my server as [UserResult] but I cannot get it to work??
What am I doing wrong?
func userSearch(keyword: String, completion: #escaping (Result<[UserResult], ResponseError>) -> Void ) {
socket.emit("userSearch", keyword)
socket.on("userFound") { ( data, ack) in
print(data) // prints below NSArray
if !data.isEmpty {
if let response = data as? [UserResult] {
print("USERS \(response)") // WILL NOT WORK?
completion(.success(response))
}
} else {
completion(.failure(.badRequest("No users found")))
}
}
}
Data from server
[<__NSArrayM 0x60000040e5b0>(
{
profileUrl = "www.address1.com";
username = chrissmith;
},
{
profileUrl = "www.address2.com";
username = johnsmith;
},
{
profileUrl = "www.address3.com";
username = alicesmith;
}
)
]
UserResult Model
struct UserResult: Decodable {
let username: String
let profileUrl: String
}
Well you are using Socket.IO library and specifically method
socket.on(clientEvent: .connect) {data, ack in
...
}
defined as
#discardableResult
open func on(clientEvent event: SocketClientEvent, callback: #escaping NormalCallback) -> UUID
using typealias:
public typealias NormalCallback = ([Any], SocketAckEmitter) -> ()
So basically at the and you are being returned data of type [Any] according to documentation.
Since you do not know what is inside your data it is better for you to unwrap objects in your array one by one (instead casting it directly to [UserResult]) and try to find out what Type there are by comparing to some set of known types as some of answers from this question suggest.
I would start with verifying the data structure with example code below , and only move on with casting to various type afterwards:
Lets assume example data1 is your data:
let dict1 = ["profileUrl":"www.address1.com","username":"chrissmith"]
let data1: NSArray = [dict1]
//printed data1:
// (
// {
// profileUrl = "www.address1.com";
// username = chrissmith;
// }
// )
if data1[0] as? [String:String] != nil {
print("We found out that first object is dictionary of [String:String]!")
}
else if data1[0] as? Dictionary<NSObject, AnyObject> != nil {
print("We found out that first object is dictionary of mixed values!")
} else {
print("We found out that first object has different data structure")
}
Hopefully this answer was at least a little bit helpfull, even though not providing direct easy solution for your problem.
I have a function that returns either a class object or nil. The function's purpose is to check if a Chat exists. The chat ID's are stored in MySQL. If the ID exists, I perform a Firebase reference to get a snapshot and then get the object. If the ID does not exist, I return nil:
func findChat(string: String) -> Chat? {
var returnValue: (Chat?)
let url = getChatsURL
let Parameters = [ "title" : string ]
Alamofire.request("\(url)", method: .post, parameters: Parameters).validate().responseString { response in
if let anyResponse = response.result.value {
self.responseFromServer = anyResponse
}
if self.responseFromServer == "" {
returnValue = nil
} else {
let ref = DatabaseReference.chats.reference()
let query = ref.queryOrdered(byChild: "uid").queryEqual(toValue: (self.responseFromServer))
query.observe(.childAdded, with: { snapshot in
returnValue = Chat(dictionary: snapshot.value as! [String : Any])
})
}
return returnValue
}
}
However, at return returnValue I am getting
Unexpected non-void return value in void function.
Any thoughts of what I could be missing?
The problem is that you are trying to return a non-void value from inside a closure, which only returns from the closure, but since that closure expects a void return value, you receive the error.
You cannot return from an asynchronous function using the standard return ... syntax, you have to declare your function to accept a completion handler and return the value from the async network call inside the completion handler.
func findChat(string: String, completion: #escaping (Chat?)->()) {
var returnValue: (Chat?)
let url = getChatsURL
let Parameters = [ "title" : string ]
Alamofire.request("\(url)", method: .post, parameters: Parameters).validate().responseString { response in
if let anyResponse = response.result.value {
self.responseFromServer = anyResponse
}
if self.responseFromServer == "" {
completion(nil)
} else {
let ref = DatabaseReference.chats.reference()
let query = ref.queryOrdered(byChild: "uid").queryEqual(toValue: (self.responseFromServer))
query.observe(.childAdded, with: { snapshot in
completion(Chat(dictionary: snapshot.value as! [String : Any]))
})
}
}
}
Then you can call this function and use the return value like this:
findChat(string: "inputString", completion: { chat in
if let chat = chat {
//use the return value
} else {
//handle nil response
}
})
Your block is executed asynchronously, but you're trying to return a value from the enclosing function. It doesn't work that way. Your findChat function needs to take a completion block itself instead of returning a value, and then you can call that completion block from the point where you're trying to say return returnValue.
I am trying to save an object with the info retrieved from another object by a query with the code below. I am retrieving the object from class test2 with a query and want to save the object to class test1. However with the code below, when I make itemObj=ob1, the class name of itemObj starts to be test2. How can I carry all the info from ob1 to itemObj while keeping the class name as test1? Is there anyway to do this. I searched the web but couldn't find any similar issue? Thank you.
var itemObj = PFObject(className: "test1")
itemObj = ob1
itemObj.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
print("saved", terminator: "")
} else {
print("error", terminator: "")
}
}
When you created the var itemObj, you created a pfobject with a particular object id. You should not do it. You can either save the ob1 directly or, pass it like this:
var itemObj = PFObject(className: "test1")
itemObj["value1"] = ob1["value1"]
itemObj["value2"] = ob1["value2"]
itemObj.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
print("saved", terminator: "")
} else {
print("error", terminator: "")
}
}
I am trying to run loadViews() after the pullData() completes and I am wondering what the best way of doing this is? I would like to set a 10 sec timeout on it as well so I can display a network error if possible. From what I have read, GCD looks like it is the way to accomplish this but I am confused on the implementation of it. Thanks for any help you can give!
//1
pullData()
//2
loadViews()
What you need is a completion handler with a completion block.
Its really simple to create one:
func firstTask(completion: (success: Bool) -> Void) {
// Do something
// Call completion, when finished, success or faliure
completion(success: true)
}
And use your completion block like this:
firstTask { (success) -> Void in
if success {
// do second task if success
secondTask()
}
}
You can achieve like this :-
func demo(completion: (success: Bool) -> Void) {
// code goes here
completion(success: true)
}
I had a similar situation where I had to init a view once the data is pulled from Parse server. I used the following:
func fetchQuestionBank(complete:()->()){
let userDefault = NSUserDefaults.standardUserDefaults()
let username = userDefault.valueForKey("user_email") as? String
var query = PFQuery(className:"QuestionBank")
query.whereKey("teacher", equalTo: username!)
query.findObjectsInBackgroundWithBlock { (objects:[AnyObject]?, error:NSError?) -> Void in
if error == nil {
if let objects = objects as? [PFObject] {
var questionTitle:String?
var options:NSArray?
for (index, object) in enumerate(objects) {
questionTitle = object["question_title"] as? String
options = object["options"] as? NSArray
var aQuestion = MultipleChoiceQuestion(questionTitle: questionTitle!, options: options!)
aQuestion.questionId = object.objectId!
InstantlyModel.sharedInstance.questionBank.append(aQuestion)
}
complete()
}
}else{
println(" Question Bank Error \(error) ")
}
}
}
And this is you call the method:
self.fetchQuestionBank({ () -> () in
//Once all the data pulled from server. Show Teacher View.
self.teacherViewController = TeacherViewController(nibName: "TeacherViewController", bundle: nil)
self.view.addSubview(self.teacherViewController!.view)
})
function1();
function2();
Use functions!! Once function1() function completed, function2() will execute.
I just wrote some Swift code for accessing Riot API, with Alamofire and SwiftyJSON.
I wrote a function func getIDbyName(SummName: String) -> String to get the summoner id.
As you can see from the code below, I am assigning the id to self.SummID.
After executing the function, I am able to println the correct id, for example "1234567". However, the return self.SummID returns "0", the same as assigned in the beginning.
I tried to mess with the code, but I simply cannot get the correct value of self.SummID outside of the Alamofire.request closure. It always remain "0" anywhere outside.
I think it has something to do with the scope of the variable. Does anyone know what is going on here?
import Foundation
import Alamofire
import SwiftyJSON
class SummInfo {
var SummName = "ThreeSmokingGuns"
var SummID = "0"
var SummChamp = "akali"
var SummS1 = "flash"
var SummS2 = "ignite"
var SummRank = "Unranked"
var SummWR = "-" //summoner's winrate
let api_key = "key"
let URLinsert = "?api_key="
init(SummName: String, SummChamp: String, SummS1: String, SummS2: String, SummRank: String, SummWR: String) {
self.SummName = SummName
self.SummChamp = SummChamp
self.SummS1 = SummS1
self.SummS2 = SummS2
self.SummRank = SummRank
self.SummWR = SummWR
}
init(SummName: String) {
self.SummName = SummName
}
func getIDbyName(SummName: String) -> String
{
let SummURL = "https://na.api.pvp.net/api/lol/na/v1.4/summoner/by-name/"
var fullURL = "\(SummURL)\(SummName)\(URLinsert)\(api_key)"
Alamofire.request(.GET, fullURL)
.responseJSON { (request, response, data, error) in
if let anError = error
{
// got an error in getting the data, need to handle it
println("error calling GET on /posts/1")
println(error)
}
else if let data: AnyObject = data // hate this but responseJSON gives us AnyObject? while JSON() expects AnyObject
// JSON(data!) will crash if we get back empty data, so we keep the one ugly unwrapping line
{
// handle the results as JSON, without a bunch of nested if loops
let post = JSON(data)
self.tempJ = post
var key = post.dictionaryValue.keys.array //not necessary
var key2 = post[SummName.lowercaseString].dictionaryValue.keys.array
self.SummID = post[key[0],key2[2]].stringValue //[profileIconId, revisionDate, id, summonerLevel, name]
//test console output
println("The post is: \(post.description)")
println(SummName.lowercaseString)
println(key)
println(key2)
println(self.SummID)
}
}
return self.SummID
}
}
The reason is that
Alamofire.request(.GET, fullURL)
.responseJSON
is an asynchronous call. This means that the call to getIDbyName will immediately return without waiting the responseJSON to finish. This is the exact reason why you get a the '0' value for ID that you have set initially.
Having said that, the solution is to have a call back closure in the getIDbyName method:
func getIDbyName(SummName: String, callback: (id:String?) ->() ) -> ()
{
let SummURL = "https://na.api.pvp.net/api/lol/na/v1.4/summoner/by-name/"
var fullURL = "\(SummURL)\(SummName)\(URLinsert)\(api_key)"
Alamofire.request(.GET, fullURL)
.responseJSON { (request, response, data, error) in
if let anError = error
{
// got an error in getting the data, need to handle it
println("error calling GET on /posts/1")
println(error)
//Call back closure with nil value
callback(nil) //Can additionally think of passing actual error also here
}
else if let data: AnyObject = data // hate this but responseJSON gives us AnyObject? while JSON() expects AnyObject
// JSON(data!) will crash if we get back empty data, so we keep the one ugly unwrapping line
{
// handle the results as JSON, without a bunch of nested if loops
let post = JSON(data)
self.tempJ = post
var key = post.dictionaryValue.keys.array //not necessary
var key2 = post[SummName.lowercaseString].dictionaryValue.keys.array
self.SummID = post[key[0],key2[2]].stringValue //[profileIconId, revisionDate, id, summonerLevel, name]
//test console output
println("The post is: \(post.description)")
println(SummName.lowercaseString)
println(key)
println(key2)
println(self.SummID)
//Pass the actual ID got.
callback(self.SummID)
}
}
return self.SummID
}
And clients should always use this API to fetch the latest ID, and can refer the attribute directly to get whatever is cached so far in SummID member.
Here is how to call this method-
object.getIDbyName(sumName){ (idString :String) in
//Do whatever with the idString
}