How to save images in ascending order in swift? - swift

Question

I am building an application in which i am using FileManager to save some images using device camera. So for Now I am saving file name as Doc-Time.
I am using below code,
func saveImageToDocumentDirectory(image: UIImage ) {
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "hh:mm:ss"
let fileName = "Doc-" + dateFormatter.string(from: Date())
let fileURL = documentsDirectory.appendingPathComponent(fileName
)
if let data = image.jpegData(compressionQuality: 1.0),!FileManager.default.fileExists(atPath: fileURL.path){
do {
try data.write(to: fileURL)
print("file saved")
} catch {
print("error saving file:", error)
}
}
}
But Here i want to as, Doc-1,Doc-2, Doc-3....
How can i do that?

Answer 1

You can achieve this by simply storing the next index of the image. Like first the index should be 1 when you used named the image as Doc-1 then the index has 2 in it and so on....
One way to store this index in UserDefaults like:
var nextImageIndex: Int {
UserDefaults.standard.integer(forKey: "NextImageIndex") + 1 //+1 if you want to start with 1
}
func incrementImageIndex() {
UserDefaults.standard.setValue(nextImageIndex, forKey: "NextImageIndex")
}
Put the above code somewhere in UIViewController to see it works.
Here is your updated method...
func saveImageToDocumentDirectory(image: UIImage ) {
guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
return
}
let fileName = "Doc-\(nextImageIndex)"
let fileURL = documentsDirectory.appendingPathComponent(fileName)
let fileAlreadyExists = FileManager.default.fileExists(atPath: fileURL.path)
if let data = image.jpegData(compressionQuality: 1.0), !fileAlreadyExists {
do {
try data.write(to: fileURL)
incrementImageIndex()
print("file saved")
} catch {
print("error saving file:", error)
}
}
}

Answer 2

Create a variable to store the document count and increment it every time your save to the document directory, then use that value in the string.
let documentKey = "documentIndex"
#objc var documentIndex: Int {
get { UserDefaults.value(forKey: documentKey) as? Int ?? 0 }
set { UserDefaults.setValue(newValue, forKey: documentKey) }
}
func saveImageToDocumentDirectory(image: UIImage ) {
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
documentIndex += 1
let fileName = "Doc-\(documentIndex)"
let fileURL = documentsDirectory.appendingPathComponent(fileName
)
if let data = image.jpegData(compressionQuality: 1.0),!FileManager.default.fileExists(atPath: fileURL.path){
do {
try data.write(to: fileURL)
print("file saved")
} catch {
print("error saving file:", error)
}
}
}