访问ABAddressBook时出错

Question

我使用以下代码访问ABAddressBook：

+ (void)connectToAddressBook {
    if(!_addressBook)
    {
        CFErrorRef error;
        _addressBook = ABAddressBookCreateWithOptions(NULL, &error);
        NSLog(@"Address book %@", _addressBook);

        if (error != nil) {
            NSLog(@"ERROR WHILE ACCESSING ADDRESS BOOK: %@", CFBridgingRelease(error));
            CFRelease(error);
        }

        if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
            ABAddressBookRequestAccessWithCompletion(_addressBook, ^(bool granted, CFErrorRef error) {
                _isAccessToContactsAllowed = granted;
            });
        }
        else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
            _isAccessToContactsAllowed = YES;
        }
        else {
            _isAccessToContactsAllowed = NO;
        }
    }
}

通讯簿很好地打开，但出于某种原因，错误不是零，而是记录当前类的名称：

ERROR WHILE ACCESSING ADDRESS BOOK: MyContactManager

为什么错误不是零？我的代码有错吗？在发生真正的错误时，我如何检测并停止访问地址簿？

Answer 1

这是我的固定方法，感谢Ilesh的反馈：

+ (void)connectToAddressBook {
    if(!_addressBook) {
        CFErrorRef *error = nil;
        _addressBook = ABAddressBookCreateWithOptions(NULL, error);

        // To test if error is not nil:
        //error = CFErrorCreate(NULL, CFSTR("Hello, world."), 111, NULL);

        if (error != nil) {
            NSLog(@"ERROR WHILE ACCESSING ADDRESS BOOK: %@", CFBridgingRelease(error));
            CFRelease(error);
        }
        else {
            if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
                ABAddressBookRequestAccessWithCompletion(_addressBook, ^(bool granted, CFErrorRef error) {
                    _isAccessToContactsAllowed = granted;
                });
            }
            else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
                _isAccessToContactsAllowed = YES;
            }
            else {
                _isAccessToContactsAllowed = NO;
            }
        }
    }
}

编辑：

看来，我最初的错误不是将错误分配给零。地址簿创建不会设置错误，除非实际存在错误。因此，我的未赋值变量指向内存中的某个随机位置，这就是我第一次尝试时出现随机错误的原因。

此外，如果有错误，ABAddressBookCreateWithOptions将返回零，所以正确的方法是：

if(_addressBook) {
    // do something
}
else {
    // there is an error
}

Answer 2

将您的全部代码替换为

+ (void)connectToAddressBook {
    if(!_addressBook)
    {
_addressBook = ABAddressBookCreateWithOptions(NULL, NULL);
    if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
        ABAddressBookRequestAccessWithCompletion(addressBook,
                                                 ^(bool granted, CFErrorRef error) {
                                                     if (granted)
                                                      dispatch_async(dispatch_get_main_queue(), ^{
                                                        _isAccessToContactsAllowed = granted; 
                                                     });

                                                         });


    }
    else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
        dispatch_async(dispatch_get_main_queue(), ^{
_isAccessToContactsAllowed = YES;

    });
    }
    else {
        UIAlertView *alert=[[UIAlertView alloc] initWithTitle:Nil message:@"You don't have permission of access contacts for access go to Setting-" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
    }
}}