How to overwrite/delete saved images in app - ios

Question

I am developing an app where user can save 13 screenshots and display them on a single view as thumbnails or as a full screen image. This is how I save the screenshots:
let fileName:String = self.stickerUsed + "saved" + ".png"
var arrayPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as! NSString
var pngFileName = arrayPaths.stringByAppendingPathComponent(fileName)
UIImagePNGRepresentation(resizeImage(screenshot!, newSize: CGSizeMake(self.view.frame.width, self.view.frame.height))).writeToFile(pngFileName, atomically:true)
NSUserDefaults.standardUserDefaults().setObject(pngFileName, forKey: self.stickerUsed)
NSUserDefaults.standardUserDefaults().synchronize()
and this is how i retrieve them:
var defaultName:String = self.stickerUsed + "saved" + ".png"
let path = NSSearchPathForDirectoriesInDomains(
.DocumentDirectory, .UserDomainMask, true)[0] as! NSString
let fileName = NSUserDefaults.standardUserDefaults()
.stringForKey(stickerUsed) ?? defaultName
let imagePath = path.stringByAppendingPathComponent(fileName)
let image = UIImage(named: imagePath )
How do i overwrite the saved images ? When i use the code to save imageof a different screenshot with same filename and then retrieve it i get the previous image that was initially saved and new image is not overwritten!

Answer 1

I made your code cleaner and fixed the problem! Comments will help you learn some basic stuff about how it works.
First, define function that gives you full filepath from filename:
func documentsPathWithFileName(fileName : String) -> String {
// Get file path to document directory root
let documentsDirectoryPath = NSSearchPathForDirectoriesInDomains(.CachesDirectory, .UserDomainMask, true)[0] as! String
return documentsDirectoryPath.stringByAppendingPathComponent(fileName)
}
And then, function that takes UIImage and saves it, or replaces it, depending:
func saveOverrideImage(screenshot : UIImage, stickerName : String) {
// Get file path poining to documents directory
let filePath = documentsPathWithFileName(stickerName)
// We could try if there is file in this path (.fileExistsAtPath())
// BUT we can also just call delete function, because it checks by itself
NSFileManager.defaultManager().removeItemAtPath(filePath, error: nil)
// Resize image as you want
let image : NSData = UIImagePNGRepresentation(resizeImage(screenshot!, newSize: CGSizeMake(self.view.frame.width, self.view.frame.height)))
// Write new image
image.writeToFile(filePath, atomically: true)
// Save your stuff to
NSUserDefaults.standardUserDefaults().setObject(stickerName, forKey: self.stickerUsed)
NSUserDefaults.standardUserDefaults().synchronize()
}
Also, following the same style, you can get image:
func imageForStickerName(stickerName : String) -> UIImage? {
// Get file path poining to documents directory
let filePath = documentsPathWithFileName(stickerName)
// Get image from file on given local url
return UIImage(contentsOfFile: filePath)
}
Hope it helps!

Answer 2

Try You can use
var error:NSError?
var resultingURL:NSURL?
let oldURL:NSURL = NSURL.fileURLWithPath("<old path>")!
let newURL:NSURL = NSURL.fileURLWithPath("<new path>")!
fileManager.replaceItemAtURL(oldURL,
withItemAtURL: newURL,
backupItemName: nil,
options: .UsingNewMetadataOnly,
resultingItemURL: &resultingURL,
error: &error)
or you can delete old file and write new on, for more details on FileManager visit here