How to save and fetch data from file in swift? - ios

Question

I want to save the response from JSON in a file and fetch from it when the network is not available. However on trying to fetch idea by disabling the wifi, the app always crashes. Are there any other ways for offline fetching in swift except saving in database??
This is the error I am getting : Could not cast value of type 'Swift._NSContiguousString' (0x109e22320) to 'NSArray'
This is what I have done so far:
Create a model
class Directory : NSObject, NSCoding {
var data : [AnyObject]
var tid : String
var vid : String
var name : String
var imgThumbnail : String
var imgMedium : String
var imgLarge : String
var child : String
// MARK: Archiving Paths
init(data:[AnyObject],tid:String,vid:String,name:String,imgThumbnail:String,imgMedium:String,imgLarge:String,child:String) {
self.data = data ?? []
self.tid = tid ?? ""
self.vid = vid ?? ""
self.name = name ?? ""
self.imgThumbnail = imgThumbnail ?? ""
self.imgMedium = imgMedium ?? ""
self.imgLarge = imgLarge ?? ""
self.child = child ?? ""
}
// MARK: NSCoding
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(data, forKey:Constants.kData)
aCoder.encodeObject(name, forKey:Constants.Directory.kName )
aCoder.encodeObject(tid, forKey: Constants.Directory.tid)
aCoder.encodeObject(vid, forKey: Constants.Directory.vid)
aCoder.encodeObject(imgThumbnail, forKey:Constants.Directory.kImageThumbnail)
aCoder.encodeObject(imgMedium, forKey: Constants.Directory.kImageMedium)
aCoder.encodeObject(imgLarge, forKey: Constants.Directory.kImageLarge)
aCoder.encodeObject(child, forKey: Constants.Directory.kChild)
}
required convenience init?(coder aDecoder: NSCoder) {
let data = aDecoder.decodeObjectForKey(Constants.kData) as! [AnyObject]
let name = aDecoder.decodeObjectForKey(Constants.Directory.kName) as! String
let tid = aDecoder.decodeObjectForKey(Constants.Directory.tid) as! String
let vid = aDecoder.decodeObjectForKey(Constants.Directory.vid) as! String
let imgThumbnail = aDecoder.decodeObjectForKey(Constants.Directory.kImageThumbnail) as! String
let imgMedium = aDecoder.decodeObjectForKey(Constants.Directory.kImageMedium) as! String
let imgLarge = aDecoder.decodeObjectForKey(Constants.Directory.kImageLarge) as! String
let child = aDecoder.decodeObjectForKey(Constants.Directory.kChild) as! String
// Must call designated initializer.
self.init(data:data,tid:tid,vid:vid,name:name,imgThumbnail:imgThumbnail,imgMedium: imgMedium,imgLarge: imgLarge, child: child)
}
}
Code for saving and loading the data from file
class func loadSavedFile(fileName: String) -> AnyObject? {
let pathString: String = Utility.fetchFilePathString(fileName)
print("Here the pathString is \(pathString)")
if NSFileManager.defaultManager().fileExistsAtPath(pathString) {
return NSKeyedUnarchiver.unarchiveObjectWithFile(pathString)!
} else {
return "File doesn't exist"
}
return ""
}
class func saveObject(object: AnyObject, toFile fileName: String) {
let pathString: String = Utility.fetchFilePathString(fileName)
NSKeyedArchiver.archiveRootObject(object, toFile: pathString)
}
class func fetchFilePathString(fileName: String) -> String {
let pathAray: [AnyObject] = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.AllDomainsMask, true)
let pathString = pathAray.last!
return NSURL(fileURLWithPath: pathString as! String).URLByAppendingPathComponent(fileName).absoluteString
}
Checking for network connection in the view controller
var directoryArr = [Directory]()
override func viewDidLoad() {
super.viewDidLoad()
if Utility.isNetworkReachable() {
Utility.saveObject([], toFile: Constants.File.kDirectory)
self.serviceCallDirectory()
} else {
self.directorie = (Utility.loadSavedFile(Constants.File.kDirectory) as? [Directory])!
self.tableView.reloadData()
}
Service Call
func serviceCallDirectory() -> Void {
let stringUrl = Constants.baseUrl + Constants.kDirectoryUrl
WebService.getRequestAPI(stringUrl, withSuccess: {(responseDic, Statusflag,error) in
if Statusflag {
self.tableView.backgroundColor = UIColor.clearColor()
self.tableView.hidden = false
let tempInfo = responseDic![Constants.kData] as! [AnyObject]
var imgthumbnail : String = ""
var imgmedium : String = ""
var imglarge : String = ""
var name : String = ""
var child : String = ""
if tempInfo.count != 0 {
for info in tempInfo {
let tid = info[Constants.Directory.tid] as! String
let vid = info[Constants.Directory.vid] as! String
if let names = info[Constants.Directory.kName] as? String {
name = names
}
if let childs = info[Constants.Directory.kChild] as? String {
child = childs
}
if let imgthumb = info[Constants.Directory.kImageThumbnail] as? String {
imgthumbnail = imgthumb
} else {
imgthumbnail = ""
}
if let imgmediumd = info[Constants.Directory.kImageMedium] as? String {
imgmedium = imgmediumd
} else {
imgmedium = ""
}
if let imglarges = info[Constants.Directory.kImageLarge] as? String {
imglarge = imglarges
}
let myModel = Directory(
data: tempInfo,
tid: tid,
vid: vid,
name: name,
imgThumbnail: imgthumbnail,
imgMedium: imgmedium,
imgLarge: "",
child: child
)
self.directorie.append(myModel)
}

Answer 1

I don't know that this is the only issue, but this code
class func loadSavedFile(fileName: String) -> AnyObject? {
let pathString: String = Utility.fetchFilePathString(fileName)
print("Here the pathString is \(pathString)")
if NSFileManager.defaultManager().fileExistsAtPath(pathString) {
return NSKeyedUnarchiver.unarchiveObjectWithFile(pathString)!
} else {
return "File doesn't exist"
}
return ""
}
Either returns an object or a string. That's not very sensible. It should return a success flag or a tuple or use a completion block. When you call this function your code expects to get back an array of directory, which in a number of cases won't happen
self.directorie = (Utility.loadSavedFile(Constants.File.kDirectory) as? [Directory])!
The error in your question indicates a different kind of data mismatch. You should try not to use AnyObject, let swift help you by type checking what you're doing...