I couldn't get any replies on my previous (related) question, so I'm wondering if slightly paraphrasing it will be of any help.
I'm encoding a few complex objects with NSKeyedArchiver and saving it to disk. Say, something like -
Class member {
int *id;
NSString *name;
NSMutableArray *array;
TempClass *object;
}
The functionality I'm trying to build is for the user to be able to save his work, lets say, while creating a new member and come back to it later. When the user finishes up, he clicks post and the data will be transmitted to a web service. If not, he just clicks save and leaves the screen and the data is persisted, so that the app can resume from that point when the user comes back. Now, once I've posted the data to the web service, I do not want to keep the data in the disk anymore and I can't really find a way to delete it.
Now, my encoding and decoding classes are functioning fine. I can use NSKeyedArchiver to save the data to disk and retrieve it using NSKeyedUnarchiver. But, my question is, how can I delete the data that I don't need anymore? Do I have to manually delete the file on the disk? Is there any way to get NSKeyedUnarchiver to delete the data that's it's returning?
Thanks,
Teja.
A very simple way to just delete it programmatically once you have posted the data:
- (BOOL) deleteFile:(NSString *) pathOfFileToDelete error:(NSError *)err {
BOOL exists = [[NSFileManager defaultManager] fileExistsAtPath: pathOfFileToDelete];
if(exists) {
[[NSFileManager defaultManager]removeItemAtPath: pathOfFileToDelete error:err];
}
return exists;
}
A Swift3 example:
do {
try FileManager.default.removeItem(atPath: path)
} catch {
// catch potential error
}
For Swift 2.0:
func deleteFile(path: String) -> Bool{
let exists = NSFileManager.defaultManager().fileExistsAtPath(path)
if exists {
do {
try NSFileManager.defaultManager().removeItemAtPath(path)
}catch let error as NSError {
print("error: \(error.localizedDescription)")
return false
}
}
return exists
}
For Swift 3.0 -> 4.1:
let fileManager = FileManager()
let fileName = "your_file_name"
//In Order to get your file path correctly
getFileURL(_ fileName: String) -> String? {
let fileURL = fileManager.urls(for: fileManager.SearchPathDirectory.documentDirectory, in: fileManager.SearchPathDomainMask.userDomainMask).first
return (fileURL?.appendingPathComponent(fileName).path)
}
//Persist Data
func persistData(_ data : Data) -> Bool{
return NSKeyedArchiver.archiveRootObject(data, toFile: getFileURL(fileName)!)
}
//Get Persisted Data
func getArchivedData() -> Data?{
return NSKeyedUnarchiver.unarchiveObject(withFile: getFileURL(fileName)!) as? Data
}
//Delete Persisted Data
func deleteArchivedUser() -> Bool{
do {
try fileManager.removeItem(atPath: getFileURL(fileName)!)
return true
} catch _ {
return false
}
}
For Swift 2.0:
do {
try NSFileManager.defaultManager().removeItemAtPath("Your_PATH")
} catch {
}
Related
I am trying to make a document based app in swiftUI with a custom UI. I want iCloud capabilities in my app. I am trying to use iCloud Document (No cloudKit) way for storing data on iCloud container. I am using UIDocument and it's working. It's storing data to iCloud and I am able to retrieve it back.
Now the thing is when I run the app on two devices (iphone and iPad) and make changes to a file on one device, the changes are not reflecting on the other device while the file or say app is open. I have to close the app and relaunch it to see the changes.
I know I have to implement NSMetadataQuery to achieve this but I am struggling with it. I don't know any objective-C. I have been searching on the internet for a good article but could not find any. Can you please tell how do I implement this feature in my app. I have attach the working code of UIDocument and my Model class.
Thank you in advance !
UIDocument
class NoteDocument: UIDocument {
var notes = [Note]()
override func load(fromContents contents: Any, ofType typeName: String?) throws {
if let contents = contents as? Data {
if let arr = try? PropertyListDecoder().decode([Note].self, from: contents) {
self.notes = arr
return
}
}
//if we get here, there was some kind of problem
throw NSError(domain: "NoDataDomain", code: -1, userInfo: nil)
}
override func contents(forType typeName: String) throws -> Any {
if let data = try? PropertyListEncoder().encode(self.notes) {
return data
}
//if we get here, there was some kind of problem
throw NSError(domain: "NoDataDomain", code: -2, userInfo: nil)
}
}
Model
class Model: ObservableObject {
var document: NoteDocument?
var documentURL: URL?
init() {
let fm = FileManager.default
let driveURL = fm.url(forUbiquityContainerIdentifier: nil)?.appendingPathComponent("Documents")
documentURL = driveURL?.appendingPathComponent("savefile.txt")
document = NoteDocument(fileURL: documentURL!)
}
func loadData(viewModel: ViewModel) {
let fm = FileManager.default
if fm.fileExists(atPath: (documentURL?.path)!) {
document?.open(completionHandler: { (success: Bool) -> Void in
if success {
viewModel.notes = self.document?.notes ?? [Note]()
print("File load successfull")
} else {
print("File load failed")
}
})
} else {
document?.save(to: documentURL!, for: .forCreating, completionHandler: { (success: Bool) -> Void in
if success {
print("File create successfull")
} else {
print("File create failed")
}
})
}
}
func saveData(_ notes: [Note]) {
document!.notes = notes
document?.save(to: documentURL!, for: .forOverwriting, completionHandler: { (success: Bool) -> Void in
if success {
print("File save successfull")
} else {
print("File save failed")
}
})
}
func autoSave(_ notes: [Note]) {
document!.notes = notes
document?.updateChangeCount(.done)
}
}
Note
class Note: Identifiable, Codable {
var id = UUID()
var title = ""
var text = ""
}
This is a complex topic. Apple do provide some sample swift code, the Document-Based App Programming Guide for iOS and iCloud Design Guide.
There is also some good third party guidance: Mastering the iCloud Document Store.
I would recommend reading the above, and then return to the NSMetaDataQuery API. NSMetaDataQuery has an initial gathering phase and a live-update phase. The later phase can remain in operation for the lifetime of your app, allowing you to be notified of new documents in your app's iCloud container.
I've Googled for a while and still cannot find the answer.
In my app, there's a function to back up the data for a user. Here's the problem: even though a user's iCloud storage is full, one can still successfully back up. However, he/she shouldn't be able to back up when his/her iCloud is full.
What I want to ask is whether it is possible to detect the remaining storage space in iCloud.
Here is the backup code:
func save(data: Data, completion: #escaping (Result<Date, Error>) -> Void) {
guard let cloudURL = cloudURL else { // cloudURL: URL?
completion(.failure(ChatBackupError.notAvailable))
return
}
let document = ChatBackupDocument(fileURL: cloudURL) // ChatBackupDocument: UIDocument
document.open { _ in
document.data = data
document.updateChangeCount(.done)
document.save(to: cloudURL, for: .forOverwriting) { success in
guard success else {
completion(.failure(ChatBackupError.saveFailed))
return
}
document.close { _ in
guard let fileModificationDate = document.fileModificationDate else {
completion(.failure(ChatBackupError.saveFailed))
return
}
completion(.success(fileModificationDate))
}
}
}
}
Thank you.
Answer is below, image is here:
I was searching how to do this for a couple of days and was only able to find people who stored UILocalNotificaations in NSUserDefaults. Saving these in NSUserDefaults seemed wrong to me because it is supposed to be used for small flags. I just now finally figured out how to store notifications in CoreData. This is Using Xcode 7.3.1 and Swift 2.2
First off you need to create a new entity in your CoreDataModel
and then add a single attribute to it. the attribute should be of type Binary Data I named my table/entity "ManagedFiredNotifications" and my attribute "notification". it should look like this:
Image linked in Question above.
Next you need to add an extension to UILocalNotification it should go like this:
extension UILocalNotification {
func save() -> Bool {
let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate
let firedNotificationEntity = NSEntityDescription.insertNewObjectForEntityForName("ManagedFiredNotifications", inManagedObjectContext: appDelegate!.managedObjectContext)
guard appDelegate != nil else {
return false
}
let data = NSKeyedArchiver.archivedDataWithRootObject(self)
firedNotificationEntity.setValue(data, forKey: "notification")
do {
try appDelegate!.managedObjectContext.save()
return true
} catch {
return false
}
}
}
Now for saving a notification all you need to do is call
UILocalNotification.save()
On the notification you would like to save. my notifications were named 'notification' so I would call notification.save()
To retrieve a notification you need a method like this
func getLocalFiredNotifications() -> [UILocalNotification]? {
let managedObjectContext = (UIApplication.sharedApplication().delegate as? AppDelegate)!.managedObjectContext
let firedNotificationFetchRequest = NSFetchRequest(entityName: "ManagedFiredNotifications")
firedNotificationFetchRequest.includesPendingChanges = false
do {
let fetchedFiredNotifications = try managedObjectContext.executeFetchRequest(firedNotificationFetchRequest)
guard fetchedFiredNotifications.count > 0 else {
return nil
}
var firedNotificationsToReturn = [UILocalNotification]()
for managedFiredNotification in fetchedFiredNotifications {
let notificationData = managedFiredNotification.valueForKey("notification") as! NSData
let notificationToAdd = NSKeyedUnarchiver.unarchiveObjectWithData(notificationData) as! UILocalNotification
firedNotificationsToReturn.append(notificationToAdd)
}
return firedNotificationsToReturn
} catch {
return nil
}
}
Note that this returns an array of UILocalNotifications.
When retrieving these if you plan on removing a few of them and then storing the list again you should remove them when you get them something like this works:
func loadFiredNotifications() {
let notifications = StudyHelper().getLocalFiredNotifications()
if notifications != nil {
firedNotifications = notifications!
} else {
// throw an error or log it
}
classThatRemoveMethodIsIn().removeFiredLocalNotifications()
}
I hope this helps someone who had the same problems that I did trying to implement this.
I am trying to save an array of a user-created class named "TopTenData". The code I used follows. Running the code indicates the file is created, but the file is NOT created. When I navigate to the path I do not find the desired file. Any help would be appreciated.
func writeArrayToPlist(array: [TopTenData]) {
if let arrayPath: String = createArrayPath() {
(array as NSArray).writeToFile(arrayPath, atomically: false)
print("Array written successfully")
print(arrayPath) // navigating this path shows no files
}
}
func createArrayPath () -> String? {
if let docsPath: String = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true).last {
return ((docsPath as NSString).stringByAppendingPathComponent("myTopTenData") as NSString).stringByAppendingPathExtension("plist")
}
return nil
}
writeToFile method of NSArray has some limitations. For example it only support these data types:
NSString
NSData
NSDate
NSNumber
NSArray
NSDictionary
For custom data types you can use NSKeyedArchiver and NSKeyedUnarchiver
See this post
I have an app I've made that has a UITableView with todoItems as an array for it. It works flawlessly and I have an export button that creates a CSV file from the UITableView data and emails it out:
// Variables
var toDoItems:[String] = []
var convertMutable: NSMutableString!
var incomingString: String = ""
var datastring: NSString!
// Mail alert if user does not have email setup on device
func showSendMailErrorAlert() {
let sendMailErrorAlert = UIAlertView(title: "Could Not Send Email", message: "Your device could not send e-mail. Please check e-mail configuration and try again.", delegate: self, cancelButtonTitle: "OK")
sendMailErrorAlert.show()
}
// MARK: MFMailComposeViewControllerDelegate Method
func mailComposeController(controller: MFMailComposeViewController, didFinishWithResult result: MFMailComposeResult, error: NSError?) {
controller.dismissViewControllerAnimated(true, completion: nil)
}
// CSV Export Button
#IBAction func csvExport(sender: AnyObject) {
// Convert tableView String Data to NSMutableString
convertMutable = NSMutableString();
for item in toDoItems
{
convertMutable.appendFormat("%#\r", item)
}
print("NSMutableString: \(convertMutable)")
// Convert above NSMutableString to NSData
let data = convertMutable.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)
if let d = data { // Unwrap since data is optional and print
print("NSData: \(d)")
}
//Email Functions
func configuredMailComposeViewController() -> MFMailComposeViewController {
let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
mailComposerVC.setSubject("CSV File Export")
mailComposerVC.setMessageBody("", isHTML: false)
mailComposerVC.addAttachmentData(data!, mimeType: "text/csv", fileName: "TodoList.csv")
return mailComposerVC
}
// Compose Email
let mailComposeViewController = configuredMailComposeViewController()
if MFMailComposeViewController.canSendMail() {
self.presentViewController(mailComposeViewController, animated: true, completion: nil)
} else {
self.showSendMailErrorAlert() // One of the MAIL functions
}
}
My question is how do I create the same CSV file, but instead of emailing, save it to file? I'm new to programming and still learning Swift 2. I understand that the section of code (data!, mimeType: "text/csv", fileName: "TodoList.csv") creates the file as an attachment. I've looked online for this and trying to understand paths and directories is hard for me. My ultimate goal is to have another UITableView with a list of these 'saved' CSV files listed. Can someone please help? Thank you!
I added the following IBAction to my project:
// Save Item to Memory
#IBAction func saveButton(sender: UIBarButtonItem) {
// Convert tableView String Data to NSMutableString
convertMutable = NSMutableString();
for item in toDoItems
{
convertMutable.appendFormat("%#\r", item)
}
print("NSMutableString: \(convertMutable)")
// Convert above NSMutableString to NSData
let data = convertMutable.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)
if let d = data { // Unwrap since data is optional and print
print("NSData: \(d)")
}
let path = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString
func writeToFile(_: convertMutable, path: String, atomically useAuxiliaryFile: Bool, encoding enc: UInt) throws {
}
}
I was struggling to find a decent simple answer to this for ages.
Here is the best way that I've found to create a csv file and even the directory you want it to be it and write to it.
//First make sure you know your file path, you can get it from user input or whatever
//Keep the path clean of the name for now
var filePath = "/Users/Johnson/Documents/NEW FOLDER/"
//then you need to pick your file name
let fileName = "AwesomeFile.csv"
//You should probably have some data to put in it
//You can even convert your array to a string by appending all of it's elements
let fileData = "This,is,just,some,dummy,data"
// Create a FileManager instance this will help you make a new folder if you don't have it already
let fileManager = FileManager.default
//Create your target directory
do {
try fileManager.createDirectory(atPath: filePath!, withIntermediateDirectories: true, attributes: nil)
//Now it's finally time to complete the path
filePath! += fileName!
}
catch let error as NSError {
print("Ooops! Something went wrong: \(error)")
}
//Then simply write to the file
do {
// Write contents to file
try fileData.write(toFile: filePath!, atomically: true, encoding: String.Encoding.utf8)
print("Writing CSV to: \(filePath!)")
}
catch let error as NSError {
print("Ooops! Something went wrong: \(error)")
}
PS. Just noticed that question is from year ago, but I hope it helps a struggling newbie like myself when they inevitably stumble upon it like I did.
convertMutable can be easily written to disk with either fun writeToFile(_ path: String, atomically useAuxiliaryFile: Bool, encoding enc: UInt) throws or func writeToURL(_ url: NSURL, atomically useAuxiliaryFile: Bool, encoding enc: UInt) throws. All you have to do is create a path or URL to write the string out to. If you are using iCloud things will be more challenging but for locally stored files you can use let path = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString to get the root path of the documents directory.
Update: Based on you first comment below here is some added info:
The first issue is that it appears as though you are looking for code you can just paste int your project without really understanding what it does. My appologies if I'm wrong, but if I'm right this is not a good route to take as you will have many issues down the road when things change.
At the bottom of your last code section you are trying to create a function inside a function which is not going to do what you want. The above mentioned functions are the declarations of two NSString functions not functions that you need to create. As NSMutableString is a subclass of NSString you can use those functions on your convertMutable variable.
Another thing you need to deal with is creating a name for the file you want to save, currently you have pasted in the line above that gets the Documents directory but does not have a file name. You will need to devise a way to create a unique filename each time you save a CSV file and add that name to the end of path. Then you can use writeToFile… or writeToURL… to write the string to the desired location.
If you find you don't fully comprehend the code you are adding then consider getting a book or finding classes about Swift (Coursera.org has a class that may be of use). There are plenty of resources out there learn the basics of software development and Swift, it will take effort and time but it will be worth it in the end if this is something you want to pursue.