I am trying to add Apple Pencil support to my mind mapping app. I already use Core Data within my app for data persistence which all works fine without any bugs.
I have my Apple Pencil features working fine but I'm having trouble storing the Apple Pencil data.
Ive tried to add a PKDrawing object to my MindMap data model but I keep getting a compile time error 'cannot find type 'PKDrawing' in scope'
As far as I am away I can store the PKDrawing object into core data and then fetch it back out when the app loads. But I'm obviously not doing something right.
Any help is greatly appreciated folks.
Thank you
Update:
So I've used:
func convertToData(pkdrawing: PKDrawing) -> Data {
let data = pkdrawing.dataRepresentation()
return data
}
Then updated my model data and savedContext which all seems to work ok. The problem is when I try and initialise the data on opening the app. I have:
func createDrawing(data: Data) -> PKDrawing {
var loadedDrawing: PKDrawing
do {
try loadedDrawing = PKDrawing.init(from: data as! Decoder)
return loadedDrawing
} catch {
print("Error loading drawing object")
return PKDrawing()
}
}
which gives me error:
Could not cast value of type 'Foundation.Data' (0x1f3851a98) to 'Swift.Decoder' (0x1ee5381a8).
2021-09-24 06:22:58.912173+0100 MindMappingApp[1137:612856] Could not cast value of type 'Foundation.Data' (0x1f3851a98) to 'Swift.Decoder' (0x1ee5381a8).
I tried:
try loadedDrawing = PKDrawing.init(from: data as! Decoder)
as:
try loadedDrawing = PKDrawing.init(from: data)
but I kept getting:
Argument type 'Data' does not conform to expected type 'Decoder'
any ideas? Thanks in advance :)
Instead of trying to store the PKDrawing directly, store the Data associated with it instead.
Your Core Data model will have a field with the type Data (or Binary Data if you're using the GUI).
When you need to actually use that data and covert to/from the PKDrawing, you can use:
init(data:) https://developer.apple.com/documentation/pencilkit/pkdrawing/3281882-init
dataRepresentation() https://developer.apple.com/documentation/pencilkit/pkdrawing/3281878-datarepresentation
Related
This question already has answers here:
Returning data from async call in Swift function
(13 answers)
Closed last year.
I am building a mobile app with swift, and am having some syntax issues as I am not a developer. The structure and logic of the application is really rough and surely incorrect, however we just need something that functions. (It is a school project and my team got no devs).
Anyways, we have a MySQL database that will be used as a middleman between our badge server/admin app, and our mobile app. Currently when you go to https://gatekeeperapp.org/service.php , you will see the current database data, taken by a php script and hosted there as JSON. Currently in Swift I have a struct with a function that takes this JSON data, and maps it to variables. The idea is to then pass these pulled variables into a separate set of functions that will check the pulled long/lat against the mobile devices location, and then return whether they match or not. This value would be updated, re-encoded to JSON, and pushed to a web service that would go about changing the values in the database so the badge server could use them.
Where I am currently I can see that values are being pulled and mapped and I can set a variable in a separate function to the pulled value, but then I can only seem to output this value internally, rather than actually use it in the function. I get a type error saying that the pulled values are of type (). How can I properly use these values? Ultimately I think I would want to convert the () to a double, so I could properly compare it to the Long/Lat of the device, and then will need to re-encode the new values to JSON.
Swift Code -- struct function
Swift code -- JSON struct
Swift code -- using pulled data
Your closure is called asynchronously, which means that the outer function where you are expecting to use the values has already returned by the time the closure is called. Instead, you probably need to call some other function from the closure, passing the values you've received.
class MyClass {
func fetchUserData() {
UserData().fetchUser { [weak self] user, error in
DispatchQueue.main.async {
if let user = user {
self?.handleSuccess(userID: user)
} else if let error = error {
self?.handleError(error)
}
}
}
}
private func handleSuccess(userID: String) {
print(userID)
// Do something with userID. Maybe assign it to a property on the class?
}
private func handleError(_ error: Error) {
print(error)
// Handle the error. Maybe show an alert?
}
}
I am currently going through the processes of migrating swift 2.3 to 3 using the most updated Kinvey SDK (version 3.3.5). They have done a ton of updates since the 1x versions. My question is has anyone successfully been able to query on the PersistableKeyID field and pull multiple objects?
I use to be able to use the "loadObjects" function which would take an array of strings as an argument. This function has since been depreciated and replaced with find(byId). See below:
dataStore.find(byId: "only takes one") { uClass, error in
if let uClass = uClass {
//succeed
print("UClass: \(uClass)")
} else {
//fail
}
The issue is, it will only take a single string as an argument. I have attempted to use the query functionality, but I cannot get it to take the "_id" field as a parameter. Using the following code:
//Just statically creating the sectionID array for now. This will dynamically be created
testIDs = ["58668307206c11177e5ab0d4", "58668307206c11177e5ab0d4", "57ad00a505a2bb55632659c3"]
let sectionStore = DataStore<Section>.collection()
let sectionQuery = Query(format: "_id IN %#", testIDs)
sectionStore.find(sectionQuery) {sectionResult, error in
if let sectionResult = sectionResult {
self.sectionsTest = sectionResult
self.sectionCollectionView.reloadData()
} else{
//Error
}
}
I receive the error:
'Invalid property name', reason: 'Property '_id' not found in object of type 'Section'
Anyone have an idea on how to perform this now that "loadObjects" has been depreciated? There is no delivered "find(byIds)" that I could find.
Jbone107,
I was able to get results with this, let me know if the below works for you.
let id:[String] = ["5855026650a816ec29012908","5855024a21400c5b492bea20"]
let query = Query(format: "_id IN %#", id)
dataStore.find(query) { data, error in
if let data = data {
//succeed
print(“Data: \(data)")
} else {
//fail
print("fetching failed")
}
}
Thanks,
Pranav,
Kinvey
Answered: Per the Data Store Guide for iOS, by default the ".collection()" is of type "cache". The "Cache" type will store data locally. This must be why "Realm" is now included with the version 3x SDK.
I updated my DataStore collection to:
let sectionStore = DataStore<Section>.collection(.network)
I added ".network" to force the query to pull from the backend rather than the cache file. This actually identified "_id" as a property and the query worked successfully. For some reason the "cache" file isn't storing this as a property.
Additional SDK Question Answered
I was having an issue pulling NSNumber from the Kinvey backend. This ended up being a similar issue related to the "cache" query. I reviewed the Realm support site as a last resort effort to try and figure this out. I found that Realm doesn't actually support type "NSNumber".
Excerpt taken from: https://realm.io/docs/swift/latest/
Realm supports the following property types: Bool, Int8, Int16, Int32, Int64, Double, Float, String, NSDate, and NSData.
Unfortunately, Kinvey doesn't support "Int" types. As a work around, I have changed them to string and am just converting back to "Double" or another type after I pull the data. However, if I just use ".network" collection types, then NSNumber still works.
Thanks,
James
I was trying to pass my swift object from the iOS app to the Watch. However, I found it works for basic types like NSString, but my custom object type.
My custom object is able to cast to NSData
I've made my object implement NSObject and NSCoding, which works well. I can do following without problem:
let encodedChordProgression = NSKeyedArchiver.archivedDataWithRootObject(chordProgressions[1])
let decodedChordProgression = NSKeyedUnarchiver.unarchiveObjectWithData(encodedChordProgression) as! ChordProgression
NSLog("get decodedChordProgression = \(decodedChordProgression.description)")
WatchConnectivity code works for NSString
In iPhone:
try WatchSessionManager.sharedManager.updateApplicationContext(["data": "mystringishere"])
with Watch:
dispatch_async(dispatch_get_main_queue()) { [weak self] in
self?.dataSourceChangedDelegates.forEach { $0.dataSourceDidUpdate(applicationContext["data"] as! NSString)}
}
works.
My custom object with WatchConnectivity Failed
However, when I switch the object to my own object, it failed by not calling the dataSourceChangedDelegates callback function. That is:
In iPhone:
let encodedChordProgression = NSKeyedArchiver.archivedDataWithRootObject(chordProgressions[1])
try WatchSessionManager.sharedManager.updateApplicationContext(["data": encodedChordProgression])
with Watch:
dispatch_async(dispatch_get_main_queue()) { [weak self] in
self?.dataSourceChangedDelegates.forEach { $0.dataSourceDidUpdate(applicationContext["data"] as! NSData)}
}
and
func dataSourceDidUpdate(encodedChordProgression: NSData) {
let chordProgression = NSKeyedUnarchiver.unarchiveObjectWithData(encodedChordProgression) as! ChordProgression
NSLog("get something here: \(chordProgression.description)")
}
What I've tried & my problem
I've tried to read the system.log of both the iPhone app and Watch app, but I couldn't find any clue, which is the biggest problem I have now.
The full code is: here (checkout 7f2a72c6004f6580e2a38a2d7fd0ed2cef8a2b2e)
NSKeyedArchiver/NSKeyedUnarchiver won't work in this way unfortunately. This is because even though you may share class files between your watchkit and iOS targets, they are essentially different classes to the compiler because they are compiled for different architectures.
What I have done to get around this issue myself (because I initially tried to do the same thing) is serialize my custom objects to a json dictionary (or json NSData if you like) and send that. Here is a github project I have made that automatically serializes your swift objects to json for you (specifically with this use case in mind).
I tried with "NSKeyedArchiver/NSKeyedUnarchiver" and this is working perfectly.
no need to go for serialization and all.
your dictionary should have same type of data and Archiver is doing it very well.
I would like to have synchronized http request results with my Core Data database. For example very basic class:
class Category: NSManagedObject {
#NSManaged var id: NSNumber
#NSManaged var name: String
#NSManaged var imageUrl: String
}
And I have this method for getting results from request:
apiManager.getRequestJsonParse(Constants.Server.BackendUrl + "categories?lang=cs", completion: { (result, error) -> Void in
completion(categories: [], error: error)
})
Result is dictionary parsed from json. It's okay but now I want to parse dictionary to my class, check if exists in database, if it exists update properties and if not than add new category to database.
My approach that I was using in apps before was that I have two classes: Category and CategoryCD (CD like Core Data) and first I parse json to Category class than for all categories I check if any CategoryCD (saved in CD) has same Id and then update, or add or other things.
Now I am thinking if there is better way how can I do it. I could each time when I download new results delete my database for this class and then add all results. The problem with this way is that what if I have something for some classes that I want keep. Like if I download and save images then I would rather still have connection between class and saved image.
I was thinking about my old approach but reduce 2 almost same classes (1 for Core Data and 1 same but for parsing) to 1 Core Data class. But then there is a problem when I init this class I must always create in database right? So It could be complicated.
What are you using for this? I think it's very common problem. You have list of items and I would like to have them available offline (with all data I downloaded before) but than when I connect to internet I would like to update with new results (not download all from server, just responses which I requested).
It is a very common problem and it has been solved hundreds of ways. BTW, This is not "synchronizing" it is "caching" for offline use.
Do not create two objects as that is redundant. Create just the Core Data objects as part of the parse.
A standard JSON parse would look like this:
Convert to Objects using NSJSONSerializer.
Fetch all unique IDs from the JSON objects using KVO
Fetch all existing objects from Core Data based on uniqueIDs
Insert all objects that do not currently exist
If you are going to update objects then #4 would do both.
Search on Stackoverflow and you will find plenty of examples of how to do this.
I do something similar in one of my apps.
Here is some generic code to fetch an item and update it. If it doesn't exist, it creates it.
func insertOrUpdateManagedObject(id: Int16, name: String) -> YourManagedObject? {
var managedObject: YourManagedObject?
if let context = self.managedObjectContext {
if let fetchResult = fetchManagedObjectWithId(id) {
managedObject = fetchResult
managedObject?.name = name
}
else {
managedPhrase = NSEntityDescription.insertNewObjectForEntityForName("YourManagedObject", inManagedObjectContext: context) as? YourManagedObject
managedObject?.id = id
managedObject?.name = name
}
}
println("Created a managed object \(managedObject)")
return managedObject
}
Just trying to update some Core Data apps with Continuity and have run into a bit of an issue with using the selected objects ID in the userInfo dictionary to display the correct data on the continuing device.
My first thought was to use the ObjectID, however on the receiving device this would never find a corresponding object in the Core Data store.
As it turns out the URL representation of the objectID contains the UUID of the store itself, and because the two stores UUID's are different this is obviously going to fail.
So I guess I could replace the Core Data store's UUID in the URL with the continuing devices UUID and use this, and no doubt it would work.
The Url seems to be of the following format
Does anyone know what the correct way would be to pass a reference to an object between two devices with core data stores that are synchronised via iCloud?
I'll answer this one myself and see if there are any better answers...
I pass the url of the objectID (from objectID.URIRepresentation) using Continuity API and on the receiving device create a new URL using the following:
url is the url passed in the NSUserActivity.userInfo dictionary
let storeUUID = self.identifierForStore()
// Switch the host component to be the local storeUUID
let newURL = NSURL(scheme: url.scheme!, host: storeUUID, path: url.path!)
func identifierForStore()->NSString? {
if let store = self.persistentStoreCoordinator?.persistentStores[0] as? NSPersistentStore {
return store.identifier
} else {
return nil
}
}
This seems to work just fine - hope it helps someone