NSMutableDictionary* dict = [NSMutableDictionary dictionary];
    [dict setObject: (__bridge id) kSecClassGenericPassword  forKey: (__bridge id) kSecClass];
    [dict setObject: MYKEY           forKey: (__bridge id) kSecAttrService];
    [dict setObject: @"0" forKey: (__bridge id) kSecValueData];
    SecItemAdd ((__bridge CFDictionaryRef) dict,NULL);

哪个工作正常.如果我想更改此项,是否有人可以为SecItemUpdate提供准确的语法？

更新：具有以下内容：

NSMutableDictionary *query = [NSMutableDictionary dictionary];
NSMutableDictionary *attributesToUpdate = [NSMutableDictionary dictionary];

[query setObject: (__bridge id) kSecClassGenericPassword forKey: (__bridge id) kSecClass];
[query setObject: MYKEY forKey: (__bridge id) kSecAttrService];
[query setObject: (id) kcfBooleanTrue forKey: (__bridge id) kSecReturnData];

NSString *numberOfBalloonsString = [NSString stringWithFormat:@"%d",numberOfBalloonsUsed];
NSData *numberOfBalloonsData = [numberOfBalloonsString dataUsingEncoding:NSUTF8StringEncoding];

[attributesToUpdate setObject: numberOfBalloonsData forKey:(__bridge id)kSecValueData];

OSStatus error = SecItemUpdate ((__bridge CFDictionaryRef) query,(__bridge CFDictionaryRef) attributesToUpdate);
NSLog(@"Error #: %ld",error);

我收到错误代码-50 =

One or more parameters passed to the function were not valid.