ios从NSUserdefaults保存和检索NSNumber

Question

I've searched but I can't find a good explanation as to why I'm still not getting the right value from my saved Integer.

This is how I saved my event Id.

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setInteger:eventSelected.eventId forKey:@"currentEvent"];

This is how I'm trying to retrieve it.

NSLog(@"user dfault %@", [NSNumber numberWithUnsignedInt:[[[NSUserDefaults standardUserDefaults] objectForKey:@"currentEvent"] unsignedIntegerValue]]);

I'm gettin gthis.

user dfault 123581200

Also, to note, event if I did intValue instead of unsignedIntegerValue , it would still give me a random id number. was wondering what I'm doing wrong.

Answer 1

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
// Convert your value to IntegerValue and Save it
[prefs setInteger:[eventSelected.eventId integerValue] forKey:@"currentEvent"];
// Dont forget to synchronize UserDefaults
[prefs synchronize];

// To Access this value
NSLog(@"%d",[prefs integerForKey:@"currentEvent"]);

Answer 2

Instead of this code NSLog(@"user dfault %@", [NSNumber numberWithUnsignedInt:[[[NSUserDefaults standardUserDefaults] objectForKey:@"currentEvent"] unsignedIntegerValue]]);

Use this

NSLog(@"user dfault %@", [[NSUserDefaults standardUserDefaults]  integerForKey:@"currentEvent"]);

Answer 3

To retrieve the integer you should use below function:

[[NSUserDefaults standardUserDefaults]  integerForKey:@"currentEvent"];

when you ask for objectForKey, it box it first and then return the object. Posting intValue will convert the address of that object into integer. Hence each time you will receive different number.

Answer 4

NSNumber给出一个指针值，而不是整数值。

Answer 5

NSNumber *number;

store:

[[NSUserDefaults standardUserDefaults] setValue:number forKey:@"Number"];

retrieving:

number = [NSNumber numberWithInteger:[[NSUserDefaults standardUserDefaults] integerForKey:@"Number"]];