I'm using 4 extensions within my app and use a group in combination with UserDefaults.init(suiteName:) to share settings between the extensions and the app.
However I've just tried adding an unwanted communications extension and found that data writing to the defaults, using the exact same way as its written in the other extensions, isn't saved.
At first I noticed data written by the UCE wasn't present when the app tried to read it, so performed an experiment and found that while the extension is running it can write data to user defaults and read it back, but the next time the extension runs, all that data has gone.
I've tried using the old UserDefaults.synchronize() method after writing the data but that makes no difference.
Why is the UC extension different from every other extension? Is it possible to write and persist data from within it?
let groupName = "group.com.mycompany.appName"
let sharedDefaults = UserDefaults.init(suiteName: groupName)
var theValue = sharedDefaults!.value(forKey: "some key")
NSLog("\(theValue)") // prints nothing, despite the extension having previously run
sharedDefaults!.set("some value", forKey: "some key"))
sharedDefaults!.synchronize()
theValue = sharedDefaults!.value(forKey: "some key")
NSLog("\(theValue)") // prints "some value"
Related
I have an app that displays and plays a list of podcasts that is fetched from a json file, I would like to add a download feature but to do this I would like to only show a download icon if the podcast has not been downloaded already, is there a way that I can save something like the id element as well as the podcast title so I could then check to see if its been downloaded and saved on the phone already? Or is there an easier way? Obviously I would like to do this before the list is shown.
You can use UserDefaults for that.
Here's an example on how to read an array from UserDefaults
// Retrieves an array of strings from disk
func getDowloadedPodcasts() -> [String] {
UserDefaults.standard.array(forKey: "downloadedPodcasts") as? [String] ?? []
}
And here's an example on how to append a new value to an array on UserDefaults
func addDownloadedPodcast(podcastId: String) {
let downloadedPodcasts = getDowloadedPodcasts()
downloadedPodcasts.append(podcastId)
UserDefaults.standard.setValue(podcastId, forKey: "downloadedPodcasts")
}
Note that this functions alone won't solve your problem nor are the best solution of your problem, they are here jsut to show how easy it can be to work with UserDefaults and to read/write from non-volatile memory
An object that helps a user share data from one place to another within your app, and from your app to other apps.
This is the statement written at the very beginning of UIPasteboard docs. But when I try to use it in two different apps accessing data set by other app I am getting nil everytime
DispatchQueue.global(qos: .background).async {
var i = 1
while(i > 0) {
let v = UIPasteboard.general.string
sleep(1)
print("Task : \(i)")
print("Value: \(v)")
i = i + 1
}
}
I am fetching data in above code and setting data as in below code.
UIPasteboard.general.string = "Hello"
NB: I have tested locally in this app it is setting data
Are you running iOS >=10? There was a privacy change regarding passing value between apps. Try reading the UIPasteBoard api doc : (https://developer.apple.com/documentation/uikit/uipasteboard).
Tl:dr You need to have both apps to be in the same app group (Communicating and persisting data between apps with App Groups)
To note: iOS apps are sandboxed. So the change in iOS 10 just enforces that feature.
EDITED: Since you can't use App Groups (different developer and/or products), you have to send data via a different channel. Try searching urlSchemes or store/fetch through a common server(tedious tho)
I am new to Swift.
I am trying to make a two-app project, where one app contains some data files and the other accesses those files.
The solution, I think, has been to use the App Groups entitlements to allow for this, and access the files through those means. I have been able to follow along with the example here: Communicating and persisting data between apps with App Groups. In particular, the 2nd answer, which is Swift-ish (maybe an older version I guess?). It does seem to work with the right entitlements. So, now the question is how can I access the file from one app, with it being apart of the another? I'm not familiar with the API's and correct functions that I can use (new to Swift, as I said).
The apps are basic. Setup as single view applications, with everything defaulted except the ViewController's, entitlements, and one has the test data. The Xcode project structure is:
testingData/
testingData/
testingData.entitlements
TestData/
testdata.txt
AppDelegate.swift
ViewController.swift
Main.storyboard
Assets.xcassets
LaunchScreen.storyboard
Info.plist
sharedContainerTest/
sharedContainerTest.entitlements
AppDelegate.swift
ViewController.swift
Main.storyboard
Assets.xcassets
LaunchScreen.storyboard
Info.plist
Products/
testingData.app
sharedContainerTest.app
The entitlements are both the same. They each have App Groups enabled, with the same string: group.com.example.name. On the testingData target, the ViewController has the following chunk in the viewDidLoad function from that example (modified for Swift 4.x):
var userDefaults = UserDefaults(suiteName: "group.com.example.name")!
userDefaults.set("user12345", forKey: "userId")
userDefaults.synchronize()
On the sharedContainerTest target, its ViewContoller has
var userDefaults = UserDefaults(suiteName: "group.com.example.name")
if let testUserId = userDefaults?.object(forKey: "userId") as? String {
print("User Id: \(testUserId)")
}
in its viewDidLoad function. As I said, this seems to work, but now what do I need to add to this to access the testdata.txt file from the testingData app? Does it need to be stored as a variable, perhaps? Or is there a Bundle object that can do this?
If this has been answered elsewhere, please kindly point me to it and I'll take this down.
After some trial and error, the answer is as follows:
Instead of passing in the string "user12345", you need to pass in the URL to the file you want to read for the userDefaults.set method as follows:
var userDefaults = UserDefaults(suiteName: "group.com.example.name")!
userDefaults.set(Bundle.main.url(forResource: "testdata", withExtension: ".txt"), forKey: "userId")
userDefaults.synchronize()
Then in the receiver app, you call that object and set the URL:
let userDefaults = UserDefaults(suiteName: "group.com.example.name")
let test = userDefaults?.object(forKey: "userId") as? String
let testURL = URL(fileURLWithPath: test!)
From here you can read in the contents as normal.
I wrote a custom Notification Content Extension for my Push Notifications like this:
The thing is, whenever the user is on a certain item in the carousel, I want the GO TO APP button to send a String to the app when it's opening, and from there, handle that string to move the user to the correct ViewController.
I already have the handling part inside the app, I just need to know how to pass that String from the Notification Content Extension to the container app.
Thanks! :)
Enable app groups in capabilities and use suite userDefaults to write the key and read it in the app
NSUserDefaults*defaults= [[NSUserDefaults alloc] initWithSuiteName:#"group.com.company.appName"];
// Write in extension
[defaults setObject:#"anyThing" forKey:#"sharedContent"];
// Read in app
[defaults objectForKey:#"sharedContent"];
If your app is configured for Universal Links or you have defined a Custom URL Scheme for your app, you can also open your app's URL (e.g. with data in query parameters) by calling
extensionContext?.open(url)
in your NotificationViewController.
iOS 13, Swift 5.
Based on the answer by Sh_Khan, here is some Swift Syntax. Obviously I have added App Group as a capability to the target of the main app + the target of the extension, naming the group as "group.ch.Blah" for this example.
Setting your app group, saving a string in our case, needed to set the type as Any cause strings not a type that is available in groups.
let localK = getPrivateKey64() as Any
let defaults = UserDefaults.init(suiteName: "group.ch.Blah")
defaults?.set(localK, forKey: "privateK")
Setting your app group, and reading the string back, needed to recast it back to string.
let defaults = UserDefaults.init(suiteName: "group.ch.Blah")
let localK = defaults?.object(forKey: "privateK") as? String
Worked perfectly with a notification service extension.
This question already has answers here:
Delete all keys from a NSUserDefaults dictionary iOS
(18 answers)
Closed 5 years ago.
I have this code to remove all UserDefaults data from the app:
let domain = Bundle.main.bundleIdentifier!
UserDefaults.standard.removePersistentDomain(forName: domain)
print(Array(UserDefaults.standard.dictionaryRepresentation().keys).count)
But I got 10 from the print line. Shouldn't it be 0?
The problem is you are printing the UserDefaults contents, right after clearing them, but you are not manually synchronizing them.
let domain = Bundle.main.bundleIdentifier!
UserDefaults.standard.removePersistentDomain(forName: domain)
UserDefaults.standard.synchronize()
print(Array(UserDefaults.standard.dictionaryRepresentation().keys).count)
This should do the trick.
Now you don't normally need to call synchronize manually, as the system does periodically synch the userDefaults automatically, but if you need to push the changes immediately, then you need to force update via the synchronize call.
The documentation states this
Because this method is automatically invoked at periodic intervals, use this method only if you cannot wait for the automatic synchronization (for example, if your application is about to exit) or if you want to update the user defaults to what is on disk even though you have not made any changes.
This answer found here https://stackoverflow.com/a/6797133/563381 but just incase here it is in Swift.
func resetDefaults() {
let defaults = UserDefaults.standard
let dictionary = defaults.dictionaryRepresentation()
dictionary.keys.forEach { key in
defaults.removeObject(forKey: key)
}
}