沙盒

沙盒根目录：NSString*home = NSHomeDirectory();

利用沙盒根目录拼接”Documents”字符串

NSString *home = NSHomeDirectory();

NSString*documents=[home stringByAppendingPathComponent:@"Documents"];

 

//创建文件

_filepath=[docPath stringByAppendingPathComponent:@"Date.text"];

 

//跳转到文件最后面

[filehandle seekToEndOfFile];

//打开个文件

NSFileHandle *filehandle=[NSFileHandlefileHandleForWritingAtPath:_filepath];

 

//将一个数据写入到文件中

[dateTime writeToFile:_filepathatomically:YES];

 

//将NSString转换成NSDate类型

NSDate *strDate=[str dataUsingEncoding:NSUTF8StringEncoding];

 

偏好设置

读取上次保存的设置

NSUserDefaults *defaults = [NSUserDefaultsstandardUserDefaults];

NSString *username = [defaults stringForKey:@"username"];

float textSize = [defaults floatForKey:@"text_size"];

BOOL autoLogin = [defaults boolForKey:@"auto_login"];