NSUserDefaults - save/laod/clear simple rample

NSUserDefaultsSample.m

// 定義名稱 define key
#define kIsActive        @"isActive"
#define kUserName        @"userName"

// 讀取資料
-(void)loadInfo {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSLog(@"Name : %@", [defaults stringForKey:kUserName]);
    NSLog(@"isActive : %@", ([defaults boolForKey:kIsActive] ? @"YES" : @"NO"));
}

// 儲存資料
-(void)saveInfo {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *userName = @"Hank";
    BOOL isActive = YES;
    [defaults setObject:userName forKey:kUserName];
    [defaults setBool:isActive forKey:kIsActive];
}

// 清除資料
-(void)clearInfo {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    
    [defaults removeObjectForKey:kUserName];
    [defaults removeObjectForKey:kIsActive];
}

// 執行
- (void)viewDidLoad
{
    [super viewDidLoad];
    
    [self saveInfo];
    [self loadInfo];
    
    [self clearInfo];
    [self loadInfo];
}