Saving Array Using Nsuserdefaults Crashes App

Saving array using NSUserDefaults crashes app

Looks like your code should work fine even with some really weird forced casting going on in your decoder method. Try like this:

class Task: NSObject, NSCoding {
    var name = String()
    var notes = String()
    var date: NSDate
    var taskCompleted: Bool
    init(name: String, notes: String, date: NSDate, taskCompleted: Bool){
        self.name = name
        self.notes = notes
        self.date = date
        self.taskCompleted = taskCompleted
    }
    required init(coder decoder: NSCoder){
        self.name = decoder.decodeObjectForKey("name") as! String
        self.notes = decoder.decodeObjectForKey("notes") as! String
        self.date = decoder.decodeObjectForKey("date") as! NSDate
        self.taskCompleted = decoder.decodeBoolForKey("taskCompleted")
    }
    func encodeWithCoder(coder: NSCoder) {
        coder.encodeObject(name, forKey: "name")
        coder.encodeObject(notes, forKey: "notes")
        coder.encodeObject(date, forKey: "date")
        coder.encodeBool(taskCompleted, forKey: "taskCompleted")
    }
}

Testing with plist files:

let task1 = Task(name: "task1", notes: "note a", date: NSDate(), taskCompleted: false)
let task2 = Task(name: "task2", notes: "note b", date: NSDate(), taskCompleted: true)

let documentsDirectory = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first!
let fileURL = documentsDirectory.URLByAppendingPathComponent("data.plist")

if let filePath = fileURL.path {
    NSKeyedArchiver.archiveRootObject([task1,task2], toFile: filePath)
    if let loadedArray = NSKeyedUnarchiver.unarchiveObjectWithFile(filePath) as? [Task] {
        print(loadedArray.count)

        print(loadedArray.first?.name ?? "")
        print(loadedArray.first?.notes ?? "")
        print(loadedArray.first!.date )
        print(loadedArray.first!.taskCompleted)

        print(loadedArray.last?.name ?? "")
        print(loadedArray.last?.notes ?? "")
        print(loadedArray.last!.date )
        print(loadedArray.last!.taskCompleted)
    }
}

App crashes when storing NSArray in NSUserDefaults

Yes they can not be saved like this in NSUserDefaults.

I am writing a code below please have a look and for more study go look apple docs okay.

Code is here:

//For Saving

NSData *dataSave = [NSKeyedArchiver archivedDataWithRootObject:yourArrayToBeSave]];
[[NSUserDefaults standardUserDefaults] setObject:dataSave forKey:@"array"];

[[NSUserDefaults standardUserDefaults] synchronize]; // this will save you UserDefaults

//For retrieving

NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:@"array"];
NSArray *savedArray = [NSKeyedUnarchiver unarchiveObjectWithData:data];

App crashes when storing NSArray in NSUserDefaults

Yes they can not be saved like this in NSUserDefaults.

I am writing a code below please have a look and for more study go look apple docs okay.

Code is here:

//For Saving

NSData *dataSave = [NSKeyedArchiver archivedDataWithRootObject:yourArrayToBeSave]];
[[NSUserDefaults standardUserDefaults] setObject:dataSave forKey:@"array"];

[[NSUserDefaults standardUserDefaults] synchronize]; // this will save you UserDefaults

//For retrieving

NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:@"array"];
NSArray *savedArray = [NSKeyedUnarchiver unarchiveObjectWithData:data];

NSUserDefaults save two arrays leading to crash

NSUserDefaults can store NSMutableArrays, but will turn them into immutable arrays.

Same goes for NSDictionary and NSMutableDictionary.

That means if you want to add an object to an array that you just extracted from the NSUserDefaults, you will have to first make it mutable first, using -mutableCopy for example, or -initWithArray.

NSArray *array = [userDefault objectForKey:@"movie"];

//This works
NSMutableArray *arr = [NSMutableArray alloc]initWithArray:array];

//This works too and is more commonly used.
NSMutableArray *arr = [array mutableCopy];

You can now modify the array arr without any trouble, and you will be able to save it just like you did before. If you retrieve it afterwards, it will be the modified array. But be careful, arrays and dictionaries are always immutable when taken from NSUserDefaults. You will have to do that "trick" everytime you want to modify an array or dictionary from the NSUserDefaults.

EDIT : after testing your code, my only assumption is that your crash-free array is simply nil when you retrieve it. Debug with breakpoints to verify this but I'm close to 101% sure.

EDIT2 : trojanfoe got that faster than I did !

Save a fetchedObject NSArray to NSUserDefaults - app crashes at launch

The PROBLEM

Xcode was not reaction because the entire computer would freeze after I ran the app.

Fixing the NSArray

My fetch request was bringing a custom object, and NSUserDefaults does not support custom objects. So I am converting the NSArray to a NSData.

Saving to NSUserDefaults crashes app?

"Any idea why?". Yes:

[[NSUserDefaults standardUserDefaults] setObject:[[DIOSSession sharedSession] user]
                                          forKey:@"diosSession"];

I don't know what [[DIOSSession sharedSession] user] is, but only a NSArray, NSDictionary, NSString, NSData, NSNumber and NSDate may be stored.

So I guess that's why.

save in userdefaults is crashing app

You first have to serialise your object into a Data instance before actually storing to UserDefaults. Fortunately, Swift 4 provides built-in tools to easily do both serialisation and deserialisation (Codable protocol).

Have a look at this tutorial where the required steps are described in-depth.

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