如何使用 NSUserDefault 将 NSArray 存储在 NSDictionary 中

Question

First of all I want to say that I am new in iOS. I am facing a problem. I've tried many things but have not achieved any success. In my app I declared a NSDictionay in my .pch file like so:

#define Default_InCategory @{@[@"Other",@"other_icon.png"], @[@"Salary",@"salary_icon.png"]]} 

These are some default values for a category. I also have an option from which the user can add custom values in this category. Due to some restrictions I am storing New Custom category in another separate key with name Custom_InCategory same as the above format. But I have not achieved any success. I am trying with the below code:

#define USERDEFAULT [NSUserDefaults standardUserDefaults]

NSMutableDictionary *tempDic =[[NSMutableDictionary alloc]initWithDictionary:[USERDEFAULT objectForKey:Custom_InCategory]];

NSArray *tempArr =@[@"CategoryName",@"imageName"];

[tempDic setObject:tempArr forKey:@"newCat"];

[USERDEFAULT setObject:tempDic Custom_InCategory];
[USERDEFAULT synchronize];

Answer 1

If you're going to store single key-value paired dictionary then we can directly store in UserDefaults.

If your dictionary is collection of dictionaries then it will throw an error while storing.

For that situation, you need to Archive your Dictionary into data and then store it to UserDefaults. When you need the dictionary, then Unarchive the data back to Dictionary as following:

Archive Dictionary to Data:

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:yourDictionary];

Store this Data to UserDefaults as following:

[[NSUserDefaults standardUserDefaults]setObject:data forKey:@"yourData"];

Get the Data from UserDefaults:

NSData *archivedData = [[NSUserDefaults standardUserDefaults]objectForKey:@"yourData"];

Unarchive Dictionary from Data:

NSDictionary *dictionary = [NSKeyedUnarchiver unarchiveObjectWithData:archivedData];

Hope it helps..

Answer 2

This code works fine:

NSMutableDictionary *tempDic = [[NSMutableDictionary alloc]init];
NSArray *tempArr =@[@"CategoryName",@"imageName"];

[tempDic setObject:tempArr forKey:@"newCat"];

NSUserDefaults *myDefaults = [NSUserDefaults standardUserDefaults];

[myDefaults setObject:tempDic forKey:@"myKey"];

NSLog(@"%@",[myDefaults objectForKey:@"myKey"]);

In the console it prints:

{
newCat =     (
    CategoryName,
    imageName
);
}

Update as per comment:

You should use Different key to store different objects like, newCat, newCat1, newCat2 etc or you can use mutablearray instead of dictionary and can add multiple object and retrieve it by it's index.

Answer 3

Swift version:

Save an array of Dictionary in UserDefaults

func save(arr: NSArray) {
    guard let data = try? NSKeyedArchiver.archivedData(withRootObject: arr , requiringSecureCoding: false) as Data
    else { fatalError("Can't encode data") }
    UserDefaults.standard.set(data, forKey: "ReferredBy")
}

Get an array of Dictionary from UserDefaults

func get() -> NSArray {

    if let unarchivedObject = UserDefaults.standard.object(forKey: "ReferredBy") as? Data {
        guard let nsArray = try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(unarchivedObject) as! NSArray else {
            return NSArray()
        }
        return nsArray            
    }
    return NSArray()
}