NSUserDefaults的使用

- (void)viewDidLoad {    [super viewDidLoad];    //需求一：不同的类型数据存入文件    //1.准备数据    NSArray *array = @[@"Bob", @20, @[@"Shell", @"Python", @"Objective-C"]];    BOOL isLogIn = YES;    NSInteger gradeValue = 4;    //2.获取单例对象，选择方法，指定不同的key    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];    [defaults setObject:array forKey:@"arrayKey"];    [defaults setBool:isLogIn forKey:@"isLogInKey"];    [defaults setInteger:gradeValue forKey:@"gradeValueKey"];    //3.调用同步方法(强制写入文件)    [defaults synchronize];    //需求二：将存入的数据读取出来    //1.获取单例对象，给定key(取决于存入指定key), 选择方法    NSArray *readArray = [defaults objectForKey:@"arrayKey"];    BOOL readLogIn = [defaults boolForKey:@"isLogInKey"];    NSInteger readInteger = [defaults integerForKey:@"gradeValueKey"];    //验证    NSLog(@"array:%@; bool:%d; integer:%ld", readArray, readLogIn, (long)readInteger);    //了解：可以删除指定key的value值    [defaults removeObjectForKey:@"gradeValueKey"];}