1.NSData-> NSString
NSString *aString = [[NSString alloc] initWithData:adataencoding:NSUTF8StringEncoding];
2.NSString->NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];
1.NSData-> NSString
NSString *aString = [[NSString alloc] initWithData:adataencoding:NSUTF8StringEncoding];
2.NSString->NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];