How to Store Levels Data - ios

Question

Im creating a game using SpriteKit but I’m not using sks files fore levels. I don’t to enter in details about the idea of the game before I release it but basically each level is auto generated based on a few numbers. So essentially what defines a level would be these numbers I would like to know where I could store this numbers. If I used sks files I would just have a file per level but in this case should I have them sorted in an array of levels? Should the array be in the level selection viewcontroller ? Should it be in a singleton class?
Basically what would be a good way to go about storing these values?

Answer 1

So the levels are auto-generated at runtime?
You could use an array of levels, or a file per level. I would just write them to one or more files in your app's documents directory. (I'd probably use one file per level, just to keep it simple and make it so you can easily add more levels without rewriting the whole game layout file each time.)
If you build your level structures out of scalar types, arrays, and dictionaries, (property list objects) then you can write the "object graph" to a property list using the NSArray or NSDictionary method write(to:).
Alternately you could make your level object conform to the Codable protocol, convert it to JSON, and save the JSON data to a file. The Codable protocol is easy to use, it's well documented by Apple, and there are tons of tutorials online.
EDIT
Note that you could also write your data to a property list using the Codable protocol. Just like the JSONEncoder and JSONDecoder classes, there are PropertyListEncoder and PropertyListDecoder classes that will convert your object graph back and forth to property list format. (Binary properties lists are more compact and faster to read and write than JSON.)
Below is a sample playground that defines a custom struct FooStruct, makes it Codable, and then uses a PropertyListEncoder to write the data to the playground's shared data directory (which you will have to set up if you want to test this code)
import UIKit
import PlaygroundSupport
struct FooStruct: Codable {
let aString: String
let anotherString: String
let anInt: Int
}
let fooArray: [FooStruct] = [FooStruct(aString: "Foo 1",
anotherString: "String 1", anInt: 4),
FooStruct(aString: "Foo 2",
anotherString: "String 2", anInt: 7)
]
let encoder = PropertyListEncoder()
encoder.outputFormat = .binary
do {
print(fooArray)
let data = try encoder.encode(fooArray)
let plistURL = playgroundSharedDataDirectory.appendingPathComponent("property list.plist")
try data.write(to: plistURL)
print("Data written to \(plistURL.path)")
} catch {
print (error)
}