How to save an array of custom struct to NSUserDefault with swift? -

i have custom struct called 'news' want append array nsuserdefault. it's showing error "type 'news' not conform protocol 'anyobject'".

i don't want change 'news' struct class since it's being used other code already. there anyway can change nsuserdefaults.standarduserdefaults().arrayforkey("savednewsarray") type [news]?

var savednews = nsuserdefaults.standarduserdefaults().arrayforkey("savednewsarray") var addsavednews = savednews as? [news] addsavednews.append(news(id: "00", title: newstitle, source: source, imageurl: imageurl, url: url)) nsuserdefaults.standarduserdefaults().setobject(addsavednews, forkey: "savednewsarray") nsuserdefaults.standarduserdefaults().synchronize() 

here 'news' struct.

public struct news {     public var id: string     public var title: string     public var source: string?     public var imageurl: string?     public var date: nsdate?     public var url: string      init(id: string, title: string, source: string, imageurl: string, url: string) {         self.id = id         self.title = title         self.source = source         self.imageurl = imageurl         self.url = url     } } 

nsuserdefaults can save small set of types: nsdata, nsstring, nsnumber, nsdate, nsarray containing these types, or nsdictionary containing these types. best bet encode struct using nskeyedunarchiver, required value conforms nscoding. make type conform this, think it's cleaner hide users , have private class internal representation, this:

struct foo {     var : string     var b : string? }  extension foo {     init?(data: nsdata) {         if let coding = nskeyedunarchiver.unarchiveobjectwithdata(data) as? encoding {             = coding.a string             b = coding.b string?         } else {             return nil         }     }      func encode() -> nsdata {         return nskeyedarchiver.archiveddatawithrootobject(encoding(self))     }      private class encoding: nsobject, nscoding {         let : nsstring         let b : nsstring?          init(_ foo: foo) {             = foo.a             b = foo.b         }          @objc required init?(coder adecoder: nscoder) {             if let = adecoder.decodeobjectforkey("a") as? nsstring {                 self.a =             } else {                 return nil             }             b = adecoder.decodeobjectforkey("b") as? nsstring         }          @objc func encodewithcoder(acoder: nscoder) {             acoder.encodeobject(a, forkey: "a")             acoder.encodeobject(b, forkey: "b")         }      } } 

then save array can map .encode on array:

let fooarray = [ foo(a: "a", b: "b"), foo(a: "c", b: nil) ] let encoded = fooarray.map { $0.encode() } nsuserdefaults.standarduserdefaults().setobject(encoded, forkey: "my-key") 

and can pass nsdata init:

let dataarray = nsuserdefaults.standarduserdefaults().objectforkey("my-key") as! [nsdata] let savedfoo = dataarray.map { foo(data: $0)! }