How to populate my tableview with a mutablearray from json

问题

So I'm fetching data from a url which is in a json format. I'm trying to display the data in my tableview but, even though it feels simple, I can't figure out how to do it.

class CompanyModel {

func getJSON() {

    let companyArray: NSMutableArray = NSMutableArray()

    let requestURL: NSURL = NSURL(string: "http://localhost/Companies/JSON.php")!
    let urlRequest: NSMutableURLRequest = NSMutableURLRequest(URL: requestURL)
    let session = NSURLSession.sharedSession()
    let task = session.dataTaskWithRequest(urlRequest) {
        (data, response, error) -> Void in

        let httpResponse = response as! NSHTTPURLResponse
        let statusCode = httpResponse.statusCode

        if (statusCode == 200) {
            print("Everyone is fine, file downloaded successfully.")

            do{

                let json = try NSJSONSerialization.JSONObjectWithData(data!, options:.AllowFragments)



                if let companies = json["companies"] as? [[String: AnyObject]] {

                    for company in companies {

                        if let name = company["name"] as? String,
                            let phoneNumber = company["phone_number"] as? String,
                            let website = company["website"] as? String,
                            let email = company["email"] as? String,
                            let address = company["address"] as? String

                        {
                        let company = CompanyModel()

                            company.name = name
                            company.phoneNumber = phoneNumber
                            company.website = website
                            company.email = email
                            company.address = address
                        }
                        companyArray.addObject(company)
                        print(companyArray)
                    }
                }
            } catch {
                print("Error with Json: \(error)")
            }

        }
        print(companyArray) <- array is populated
    }
    print(companyArray) <- array is empty
    task.resume()
}
}

I know i've done it before....I'm guessing in viewDidLoad() I'd call CompanyModel().getJSON() which would fetch the data, then store it in an empty array but my mind feels blank on how to do it.

I can't declare a variable of NSarray and store the data of it the variable directly for me to then populate the tableview. Nevertheless, I hope this explains what I'm trying to acheive.

回答1:

Well first change the function to return your company array :

func getJSON() -> NSMutableArray {

}

By the end of the for loop return the company array

for company in companies {

 }

After your array is populated, return the array inside this block:

dispatch_async(dispatch_get_main_queue(), { 

    return companyArray

})

And after task.resume() return the array:

return companyArray

From anywhere you wanna call this class and get the array :

Get a reference of the class

Let companyModal = CompanyModel()

And in anywhere you have your table view and the class let's say in viewDidLoad, you should first have NSMutableArray.

var arraySource = NSMutableArray()

And in viewDidLoad :

arraySource = companyModal.getJSON()

And to show the data in tableView do :

Mytableview.reloadData()

回答2:

You can't use return within the closure of an asynchronous network request, you have to use a callback instead.

You need a NSMutableArray from the request, so first, let's make a callback for this:

completion: (array: NSMutableArray)->()

We add this callback to the method signature:

func getJSON(completion: (array: NSMutableArray)->())

And then at the location where the array will be available, we place this completion handler:

class CompanyModel {
    func getJSON(completion: (array: NSMutableArray)->()) {
        let companyArray: NSMutableArray = NSMutableArray()
        let requestURL: NSURL = NSURL(string: "http://localhost/Companies/JSON.php")!
        let urlRequest: NSMutableURLRequest = NSMutableURLRequest(URL: requestURL)
        let session = NSURLSession.sharedSession()
        let task = session.dataTaskWithRequest(urlRequest) {
            (data, response, error) -> Void in
            let httpResponse = response as! NSHTTPURLResponse
            let statusCode = httpResponse.statusCode
            if (statusCode == 200) {
                do{
                    let json = try NSJSONSerialization.JSONObjectWithData(data!, options:.AllowFragments)
                    if let companies = json["companies"] as? [[String: AnyObject]] {
                        for company in companies {
                            if let name = company["name"] as? String,
                                let phoneNumber = company["phone_number"] as? String,
                                let website = company["website"] as? String,
                                let email = company["email"] as? String,
                                let address = company["address"] as? String {
                                let company = CompanyModel()
                                company.name = name
                                company.phoneNumber = phoneNumber
                                company.website = website
                                company.email = email
                                company.address = address
                                companyArray.addObject(company)
                            }
                        }

                        // CALLBACK HERE
                        completion(array: companyArray)

                    }
                } catch {
                    print("Error with Json: \(error)")
                }
            }
        }
        task.resume()
    }
}

Now to get the array from the network we use a trailing closure like this:

getJSON { (array) in
    print(array)
}

来源：https://stackoverflow.com/questions/37445069/how-to-populate-my-tableview-with-a-mutablearray-from-json