简单的数据存储

> 1.简单的存储字符串，状态，数据类型

// 存储数据

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

// 字符串

- (void)setObject:(id)value forKey:(NSString *)defaultName;

( [defaults setObject:self.accountField.text forKey:MJAccountKey]; )

// 开关状态

- (void)setBool:(BOOL)value forKey:(NSString *)defaultName;

 [defaults synchronize];

// 读取数据

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

// 字符串

self.accountField.text = [defaults objectForKey:MJAccountKey];

// 开关状态

- (BOOL)boolForKey:(NSString *)defaultName;

> 2.对象存储到文件中的数组中

// 文件路径

#define MJContactsFilepath [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"contacts.data"]

// 从文件中读取数组

contacts = [NSKeyedUnarchiver unarchiveObjectWithFile:MJContactsFilepath]

// 归档,将数组存放到文件中

[NSKeyedArchiver archiveRootObject:self.contacts toFile:MJContactsFilepath];