How to set Dictionary in NSUserDefault in swift?

问题:

I've a mutable dictionary (in form of [Int:Int]) and want that to save it. I would use NSUserDefaults like that:

    var myDic: NSMutableDictionary = [:]
        myDic = [1:2]
        NSUserDefaults.standardUserDefaults().setObject(myDic, forKey: "myDic")

but with that I get an error:

Thread 1: signal SIGABRT

I have no idea why.

回答1:

setObject(_:forKey:) can’t accept Dictionary with a key which is integer type. The method requires property-list objects, but myDic = [1:2] is not property-list object.

There are two documents about it.

setObject(_:forKey:) of NSUserDefaults

The value parameter can be only property list objects: NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. For NSArray and NSDictionary objects, their contents must be property list objects.

About Property Lists

And although NSDictionary and CFDictionary objects allow their keys to be objects of any type, if the keys are not string objects, the collections are not property-list objects.

If you set a integer-key to Dictionary, the Dictionary object cannot be used for a value of setObject. You have to use a string for the key like this:

myDic = ["1": 2]