XML data save in NSUserDefaults or in Documents Directory - ios

Question

I am making an simple news app, and trying to save (title, description, date, image with its data) in NSUserDefaults for offline read. I want when it save data in NSUserDefaults, it shows in offline and also when new data is available it rewrite or replace with previous data.
I know how to save string arrays in NSUserDefaults but did't know properly about how image saved in NSUserDefaults. I am trying to make logic of saving data and check it if new data is available but did't get success, also splash screen is take more time to disappear , is it due to loading data from server or due to slow internet connection?
Can anyone please check my code for fix it.
Thanks
class ViewController2: UIViewController ,NSXMLParserDelegate {
let newsDefaults = NSUserDefaults.standardUserDefaults()
#IBOutlet weak var tableView: UITableView!
var parser = NSXMLParser()
var posts = NSMutableArray()
var elements = NSMutableDictionary()
var element = NSString()
var title1 = NSMutableString()
var date = NSMutableString()
var link = NSMutableString()
var des = NSMutableString()
var img2 = NSMutableString()
var NSUserDefaultsTitle : [NSString] = []
var NSUserDefaultsDate : [NSString] = []
var NSUserDefaultsDes : [NSString] = []
var NSUserDefaultsImage : [UIImage] = []
typealias CompletionHandler = (image: UIImage) -> Void
var attrsUrl : [String : NSString]!
var urlPic : NSString?
var postLink: String = String()
override func viewDidLoad() {
super.viewDidLoad()
self.configure()
self.beginParsing()
}
override func viewWillAppear(animated: Bool) {
// if let HaveTitle = newsDefaults.objectForKey("t"){
// NSUserDefaultsTitle = HaveTitle.mutableCopy() as! [NSString]
// }
// if let HaveDate = newsDefaults.objectForKey("d"){
// NSUserDefaultsDate = HaveDate.mutableCopy() as! [NSString]
// }
// if let HaveDes = newsDefaults.objectForKey("des"){
// NSUserDefaultsDes = HaveDes.mutableCopy() as! [NSString]
// }
// if let imageData = newsDefaults.objectForKey("imgData"){
// NSUserDefaultsImage = imageData.mutableCopy() as! [UIImage]
// }
//
// print(newsDefaults.objectForKey("d"))
}
func beginParsing()
{
posts = []
parser = NSXMLParser(contentsOfURL:(NSURL(string: "http://www.voanews.com/api/zq$omekvi_"))!)!
parser.delegate = self
parser.parse()
tableView!.reloadData()
}
//XMLParser Methods
func parser(parser: NSXMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String])
{
element = elementName
if (elementName as NSString).isEqualToString("item")
{
elements = NSMutableDictionary()
elements = [:]
title1 = NSMutableString()
title1 = ""
date = NSMutableString()
date = ""
link = NSMutableString()
link = ""
des = NSMutableString()
des = ""
img2 = NSMutableString()
img2 = ""
}
if elementName == "enclosure" {
attrsUrl = attributeDict as [String: NSString]
urlPic = attrsUrl["url"]
print(urlPic!, terminator: "")
}
}
func parser(parser: NSXMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?)
{
if (elementName as NSString).isEqualToString("item") {
if !title1.isEqual(nil) {
elements.setObject(title1, forKey: "title")
}
if !date.isEqual(nil) {
elements.setObject(date, forKey: "pubDate")
}
if !link.isEqual(nil) {
elements.setObject(link, forKey: "link")
}
if !des.isEqual(nil){
elements.setObject(des, forKey: "description")
}
if !img2.isEqual(nil){
elements.setObject(urlPic!, forKey: "enclosure")
}
posts.addObject(elements)
//
// if let HaveData = newsDefaults.objectForKey("post"){
//
// }else{
//
//// newsDefaults.setObject(self.posts.valueForKey("title"), forKey: "t")
//// newsDefaults.setObject(self.posts.valueForKey("pubDate"), forKey: "d")
//// newsDefaults.setObject(self.posts.valueForKey("description"), forKey: "des")
//
// newsDefaults.setObject(posts, forKey: "post")
//
print("elementName")
// }
}
print("didEndElement")
}
func parser(parser: NSXMLParser, foundCharacters string: String)
{
if element.isEqualToString("title") {
title1.appendString(string)
} else if element.isEqualToString("pubDate") {
date.appendString(string)
print(date)
}
else if element.isEqualToString("link"){
link.appendString(string)
}else if element.isEqualToString("description"){
des.appendString(string)
}else if element.isEqualToString("enclosure"){
img2.appendString(string)
}
print("foundCharacter")
}
private func configure() {
self.navigationController?.navigationBar.titleTextAttributes = [NSFontAttributeName: UIFont.boldSystemFontOfSize(20.0), NSForegroundColorAttributeName: UIColor.whiteColor()]
self.tableView.registerNib(UINib(nibName: "2ImageCell", bundle: nil), forCellReuseIdentifier: "imageCell")
self.tableView.delegate = self
self.tableView.dataSource = self
self.fillNavigationBar(color: UIColor(red: 252.0/255.0, green: 0, blue: 0, alpha: 1.0))
}
private func fillNavigationBar(color color: UIColor) {
if let nav = self.navigationController {
nav.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
nav.navigationBar.shadowImage = UIImage()
for view in nav.navigationBar.subviews {
if view.isKindOfClass(NSClassFromString("_UINavigationBarBackground")!) {
if view.isKindOfClass(UIView) {
(view as UIView).backgroundColor = color
}
}
}
}
}
}
extension ViewController2: UITableViewDelegate, UITableViewDataSource {
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
self.tableView.deselectRowAtIndexPath(indexPath, animated: true)
let view = ImageModalView2.instantiateFromNib()
view.des.text = posts.objectAtIndex(indexPath.row).valueForKey("description") as? String
downloadFileFromURL(NSURL(string: self.posts.objectAtIndex(indexPath.row).valueForKey("enclosure") as! String)!, completionHandler:{(img) in
dispatch_async(dispatch_get_main_queue(), { () -> Void in
view.image = img
})
})
let window = UIApplication.sharedApplication().delegate?.window!
let modal = PathDynamicModal.show(modalView: view, inView: window!)
view.closeButtonHandler = {[weak modal] in
modal?.closeWithLeansRandom()
return
}
}
#IBAction func printData(sender: AnyObject) {
print(NSUserDefaultsImage)
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return 80.0
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return posts.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCellWithIdentifier("imageCell", forIndexPath: indexPath) as! ImageCell2
// if let picURL = user["picture"].string, url = NSURL(string: picURL) {
// if let data = NSData(contentsOfURL: url) {
// cell!.imageView?.image = UIImage(data: data)
// }
cell.titleLabel.text = posts.objectAtIndex(indexPath.row).valueForKey("title") as! NSString as String
// if NSUserDefaultsImage {
// cell.sideImageView.image = NSUserDefaultsImage[indexPath.row]
// }else{
downloadFileFromURL(NSURL(string: self.posts.objectAtIndex(indexPath.row).valueForKey("enclosure") as! String)!, completionHandler:{(img) in
dispatch_async(dispatch_get_main_queue(), { () -> Void in
cell.sideImageView.image = img
// self.NSUserDefaultsImage.append(img)
// print(img)
// self.newsDefaults.setObject(self.NSUserDefaultsImage, forKey: "imgData")
})
})
// }
//cell.date.text = posts.objectAtIndex(indexPath.row).valueForKey("pubDate") as? String
//cell.sideImageView?.contentMode = UIViewContentMode.ScaleAspectFit
//cell.sideImageView?.image = image
cell.titleLabel.userInteractionEnabled = false
cell.titleLabel.editable = false
cell.titleLabel.selectable = false
return cell
}
func downloadFileFromURL(url1: NSURL?,completionHandler: CompletionHandler) {
// download code.
if let url = url1{
let priority = DISPATCH_QUEUE_PRIORITY_HIGH
dispatch_async(dispatch_get_global_queue(priority, 0)) {
let data = NSData(contentsOfURL: url)
if data != nil {
print("image downloaded")
completionHandler(image: UIImage(data: data!)!)
}
}
}
}
}

Answer 1

In order to save images to NSUserDefaults you will need to turn it into NSData as there are only certain types that are allowed in there.
As for the idea of storing information in there for offline viewing.... That sounds more like a job for the Applications Document directory. You should be able to use the NSCoding protocol in your objects and write all of your information to the disk by calling
NSKeyedArchiver:archiveRootObject:toFile on the main object and it will call encodeWithCoder on all the child objects.

Answer 2

Saving large data in NSUserDefault in not recommended by Apple and we should not save large data. NSUserDefault or Keychain we use to store "Username", "Password" like less information.
You can use CoreData or Sqlite to do operatation with Data.