Save Data to .plist File in Swift

Apparently the file is not in a writable location, so I created it in the documents directory.

var paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
var path = paths.stringByAppendingPathComponent("data.plist")
var fileManager = NSFileManager.defaultManager()
if (!(fileManager.fileExistsAtPath(path)))
{
    var bundle : NSString = NSBundle.mainBundle().pathForResource("data", ofType: "plist")
    fileManager.copyItemAtPath(bundle, toPath: path, error:nil)
}
data.setObject(object, forKey: "object")
data.writeToFile(path, atomically: true)

Then, it has to be read from the documents directory.

var paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
var path = paths.stringByAppendingPathComponent("data.plist")
let save = NSDictionary(contentsOfFile: path)

Swift 3:

func loadData() {
    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true) as NSArray
    let documentDirectory = paths[0] as! String
    let path = documentDirectory.appending("myData.plist")
    let fileManager = FileManager.default
    if(!fileManager.fileExists(atPath: path)){
        if let bundlePath = Bundle.main.path(forResource: "myData", ofType: "plist"){
            let result = NSMutableDictionary(contentsOfFile: bundlePath)
            print("Bundle file myData.plist is -> \(result?.description)")
            do{
                try fileManager.copyItem(atPath: bundlePath, toPath: path)
            }catch{
                print("copy failure.")
            }
        }else{
            print("file myData.plist not found.")
        }
    }else{
        print("file myData.plist already exits at path.")
    }

    let resultDictionary = NSMutableDictionary(contentsOfFile: path)
    print("load myData.plist is ->\(resultDictionary?.description)")

    let myDict = NSDictionary(contentsOfFile: path)
    if let dict = myDict{
        myItemValue = dict.object(forKey: myItemKey) as! String?
        txtValue.text = myItemValue
    }else{
        print("load failure.")
    }
}

Read and Write plist file in swift

Use writeToFile:options:error: and see what the error says:

var error: NSError?
var bytes = NSKeyedArchiver.archivedDataWithRootObject(data)
if !bytes.writeToFile(path, options: nil, error: &error) {
    if let actualError = error {
        println(actualError)
    }
}

Check in Xcode 10 swift 4.1

//TODO: for wtite in .plist file
        let docsBaseURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let customPlistURL = docsBaseURL.appendingPathComponent("custom.plist")
        print(customPlistURL.absoluteString)
        let dic:[String:Any] = ["key":"val"]
        // Swift Dictionary To Data.
        do  {
        let data = try PropertyListSerialization.data(fromPropertyList: dic, format: PropertyListSerialization.PropertyListFormat.binary, options: 0)
            do {
                try data.write(to: customPlistURL, options: .atomic)
                print("Successfully write")
            }catch (let err){
                print(err.localizedDescription)
            }
        }catch (let err){
            print(err.localizedDescription)
        }