- (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"];
    
    
}