swift - Save and Load Core Graphic UIImage Array on watchOS -

i able save uiimage array created on apple watch watchos , play series of images animation group background. can make image array , play cannot figure out how store/save these images can retrieve/load them next time run app don't have build them every time app runs.

here example of how building images core graphics (swift 3):

import watchkit import foundation   class interfacecontroller: wkinterfacecontroller {     @iboutlet var colourgroup: wkinterfacegroup!      override func awake(withcontext context: anyobject?)     {         super.awake(withcontext: context)      }      override func willactivate()     {         var imagearray: [uiimage] = []         imagenumber in 1...250         {             let newimage: uiimage = drawimage(fade: cgfloat(imagenumber)/250.0)             imagearray.append(newimage)         }          let animatedimages = uiimage.animatedimage(with:imagearray, duration: 10)          colourgroup.setbackgroundimage(animatedimages)         let imagerange: nsrange = nsrange(location: 0, length: 200)         colourgroup.startanimatingwithimages(in: imagerange, duration: 10, repeatcount: 0)          super.willactivate()     }      func drawimage(fade: cgfloat) -> uiimage     {         let boxcolour: uicolor = uicolor(red: 1.0, green: 1.0, blue: 1.0, alpha: fade)          let opaque: bool = false         let scale: cgfloat = 0.0          let bounds: cgrect = wkinterfacedevice.current().screenbounds          let imagesize: cgsize = cgsize(width: bounds.width, height: 20.0)           uigraphicsbeginimagecontextwithoptions(imagesize, opaque, scale)          let radius: cgfloat = imagesize.height/2.0          let rect: cgrect = cgrect(x: 0.0, y: 0.0, width: imagesize.width, height: imagesize.height)          let selectorbox: uibezierpath = uibezierpath(roundedrect: rect, cornerradius: radius)          let boxlinewidth: double = 0.0         selectorbox.linewidth = cgfloat(boxlinewidth)         boxcolour.setfill()         selectorbox.fill()          // return image         let result: uiimage = uigraphicsgetimagefromcurrentimagecontext()!         uigraphicsendimagecontext()         return result      }      override func diddeactivate()     {         // method called when watch view controller no longer visible         super.diddeactivate()     }  } 

basically looking way save , load [uiimage] in manner can use uiimage.animatedimage(with:[uiimage], duration: timeinterval) array

is there way save image array can load next time run app rather rebuild images?

thanks

greg

nskeyedarchiver , nskeyedunarchiver did trick. here swift code xcode 8b4:

override func willactivate() {     var imagearray: [uiimage] = []      let filename: string = "therings"     let filemanager = filemanager.default     let url = filemanager.urls(for: .documentdirectory, in: .userdomainmask).first! nsurl     let theurl: url = url.appendingpathcomponent(filename)!       if let rings = nskeyedunarchiver.unarchiveobject(withfile: theurl.path) as? [uiimage]     {         print("retrieving rings - found rings")         imagearray = rings     }     else     {         print("retrieving rings - can't find rings, building new ones")          imagenumber in 1...250         {             let newimage: uiimage = drawimage(fade: cgfloat(imagenumber)/250.0)             imagearray.append(newimage)         }          nskeyedarchiver.archiverootobject(imagearray, tofile: theurl.path)     }      let animatedimages = uiimage.animatedimage(with:imagearray, duration: 10)      colourgroup.setbackgroundimage(animatedimages)     let imagerange: nsrange = nsrange(location: 0, length: 200)     colourgroup.startanimatingwithimages(in: imagerange, duration: 10, repeatcount: 0)      super.willactivate() }