Data from URL with Swift

Question

I am working on an app that pulls data from a URL.

Here is my code

import UIKit

class ViewController: UIViewController {

@IBOutlet var tellMe: UITextView!
var dataValues: NSArray = []


override func viewDidLoad() {
    super.viewDidLoad()
    loadData()
    // Do any additional setup after loading the view, typically from a nib.
}
func loadData(){
    let dataUrl = NSURL(string: "http://fitgym.mynmi.net/fitgymconnection.php")
    let theData = NSData(contentsOf: dataUrl! as URL)
    let dataLine = dataValues[0]
    dataValues = try! JSONSerialization.jsonObject(with: theData! as Data, options: JSONSerialization.ReadingOptions.mutableContainers) as! NSArray
    tellMe.text = (dataLine as AnyObject)["cap_percentage"] as? String
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

In addition to this, I have added "App Transport Security Settings" and within that "Allow Arbitrary Loads" is set to "YES"

As it stands right now, I am just trying to pull the information from the URL and display it in my text view named tellMe

Whenever I run this code, I get a SIGABRT error.

Within the console I am seeing:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArray0 objectAtIndex:]: index 0 beyond bounds for empty NSArray'
*** First throw call stack:
(
    0   CoreFoundation                      0x00000001099d434b __exceptionPreprocess + 171
    1   libobjc.A.dylib                     0x000000010943c21e objc_exception_throw + 48
    2   CoreFoundation                      0x00000001099ebddd -[__NSArray0 objectAtIndex:] + 93
    3   DatabaseOne                         0x0000000108daf67a _TFC11DatabaseOne14ViewController8loadDatafT_T_ + 346
    4   DatabaseOne                         0x0000000108daf495 _TFC11DatabaseOne14ViewController11viewDidLoadfT_T_ + 101
    5   DatabaseOne                         0x0000000108daf502 _TToFC11DatabaseOne14ViewController11viewDidLoadfT_T_ + 34
    6   UIKit                               0x0000000109f9906d -[UIViewController loadViewIfRequired] + 1258
    7   UIKit                               0x0000000109f994a0 -[UIViewController view] + 27
    8   UIKit                               0x0000000109e63045 -[UIWindow addRootViewControllerViewIfPossible] + 71
    9   UIKit                               0x0000000109e63796 -[UIWindow _setHidden:forced:] + 293
    10  UIKit                               0x0000000109e770a9 -[UIWindow makeKeyAndVisible] + 42
    11  UIKit                               0x0000000109df0259 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4818
    12  UIKit                               0x0000000109df63b9 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1731
    13  UIKit                               0x0000000109df3539 -[UIApplication workspaceDidEndTransaction:] + 188
    14  FrontBoardServices                  0x000000010d78076b __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 24
    15  FrontBoardServices                  0x000000010d7805e4 -[FBSSerialQueue _performNext] + 189
    16  FrontBoardServices                  0x000000010d78096d -[FBSSerialQueue _performNextFromRunLoopSource] + 45
    17  CoreFoundation                      0x0000000109979311 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    18  CoreFoundation                      0x000000010995e59c __CFRunLoopDoSources0 + 556
    19  CoreFoundation                      0x000000010995da86 __CFRunLoopRun + 918
    20  CoreFoundation                      0x000000010995d494 CFRunLoopRunSpecific + 420
    21  UIKit                               0x0000000109df1db6 -[UIApplication _run] + 434
    22  UIKit                               0x0000000109df7f34 UIApplicationMain + 159
    23  DatabaseOne                         0x0000000108db1a9f main + 111
    24  libdyld.dylib                       0x000000010cfef68d start + 1
    25  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

What am I doing wrong here?

Prerak Sola · Accepted Answer · 2017-01-26 16:05:33Z

3

You are trying to fetch data from an empty array at let dataLine = dataValues[0] and hence you are getting the error:

index 0 beyond bounds for empty NSArray

Add that line after you get the data in dataValues.

Hence, it should be like:

dataValues = try! JSONSerialization.jsonObject(with: theData! as Data, options: JSONSerialization.ReadingOptions.mutableContainers) as! NSArray
let dataLine = dataValues[0]

answered Jan 26, 2017 at 16:05

Prerak Sola

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1 Comment

Darthmaul Over a year ago

That was it! Thank you very much!!

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