NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

// saving an NSInteger
[prefs setInteger:42 forKey:@"integerKey"];

// saving a Double
[prefs setDouble:3.1415 forKey:@"doubleKey"];

// saving a Float
[prefs setFloat:1.2345678 forKey:@"floatKey"];

// This is suggested to synch prefs, but is not needed (I didn't put it in my tut)
[prefs synchronize];

检索

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

// getting an NSInteger
NSInteger myInt = [prefs integerForKey:@"integerKey"];

// getting an Float
float myFloat = [prefs floatForKey:@"floatKey"];

NSString *valueToSave = @"someValue";
[[NSUserDefaults standardUserDefaults] setObject:valueToSave forKey:@"preferenceName"];
[[NSUserDefaults standardUserDefaults] synchronize];

然后再拿回来

NSString *savedValue = [[NSUserDefaults standardUserDefaults]
    stringForKey:@"preferenceName"];

下面是如何对Swift做同样的事情;

var valueToSave = "someValue"
NSUserDefaults.standardUserDefaults().setObject(valueToSave, forKey: "preferenceName")

以后把它拿回来;

if let savedValue = NSUserDefaults.standardUserDefaults().stringForKey("preferenceName") {
    // Do something with savedValue
}

在Swift 3.0中

var valueToSave = "someValue"
UserDefaults.standard.set(valueToSave, forKey: "preferenceName")

if let savedValue = UserDefaults.standard.string(forKey: "preferenceName") {

}

斯威夫特更新了:

let userID = "BOB"  

宣布userDefaults:

let defaults = UserDefaults.standard
defaults.setValue(userID, forKey: "userID")

并得到它:

let userID = defaults.object(forKey: "userID")

-(void)saveToUserDefaults:(NSString*)string_to_store keys:(NSString *)key_for_the_String
{
    NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];

    if (standardUserDefaults) {
        [standardUserDefaults setObject:string_to_store forKey:key_for_the_String];
        [standardUserDefaults synchronize];
    }
}

叫它:

[self saveToUserDefaults:@"string_to_store" : @"key_for_the_string"];

使用以下方法检索字符串:

NSString * stored_string = [[NSUserDefaults standardUserDefaults] stringforkey:key_for_the_String]

就像这样:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

然后检索:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

你应该看看苹果的NSUserDefaults类参考，也可以看看这个教程:iPhone编程教程-使用NSUserDefaults保存/检索数据