如何编写 ObjectiveC 完成块

我所处的情况是，需要从视图控制器调用一个类方法，让它做它该做的事情，但只有在类方法完成后才能执行一些操作.

(我想我需要的是一个完成块，但如果我错了，请纠正我.)

情况如下:

我在用Parse.我的应用程序后端的com.当用户注册帐户时，他们会在弹出窗口中输入姓名、公司和其他信息，然后单击提交.submit按钮链接到一个类方法(如下所示)，该类方法接受他们的PFUser对象和公司名称，并创建一些数据库对象.函数完成后，使用委托关闭弹出窗口.

问题是，我需要以特定的顺序创建这些对象，因为它们彼此依赖objectId的存在.问题是，取消弹出窗口的委托方法在单击submit后立即被调用，因为它是堆栈上的下一个.

保存解析对象时，调用如下所示的方法:

[someParseObject saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
    // Code here runs AFTER the method completes.
    // This also happens on another thread which
    // I'd like to implement as well.
}];

所以，我需要弄清楚如何做以下事情:

SignUpViewController.m

myUserOrg *userOrg = [myUserOrg object]; // myUserOrg = Custom PFObject Subclass

// My method that takes in a user object and a string, creates
// the database objects in order.
[userOrg registerNewUserOrgWithUser:(PFUser*) andCompanyName:(NSString*) companyName withBlock(somethingHere)block {

    if(error) {
        NSLog(@"Unable to create org!");
    } else {
        NSLog(@"Created Org!");
        [self.delegate dismissSignupView];
}

如果您需要更多信息或澄清，请告诉我.

提前谢谢！

---------编辑一个----------

好的，那么几个相当大的时间单位之后，这就是我想到的.整个实现可以得到更好的简化，并进行少得多的api调用，但将在这方面起作用.它还有其他几个突出的问题，但这只是第一步.

方法调用:

[testOrg registerNewUserOrgWithUser:currentUser
         creatingOrgContactWithName:@"MyBigHappy Corp."
                          withBlock:^(BOOL succeeded, NSError *error) {
                              if (error) {
                                  NSLog(@"Not working");
                              } else {
                                  NSLog(@"Working!");
                              }
                          }];

方法实现:

@implementation MYUserOrg

@dynamic orgContact;
@dynamic orgDisplayName;
@dynamic members;
@dynamic contacts;

+ (NSString *)parseClassName {
    return @"MYUserOrg";
}

dispatch_queue_t NewUserOrgRegistrationQueue;

-(void)registerNewUserOrgWithUser:(MYUser*)user
       creatingOrgContactWithName:(NSString*) orgContactName
                        withBlock:(MYBooleanResultBlock) block {

    NewUserOrgRegistrationQueue = dispatch_queue_create("com.myapp.initialOrgCreationQueue", NULL);

    dispatch_async(NewUserOrgRegistrationQueue, ^{

        NSMutableArray *errors = [[NSMutableArray alloc] init];

        // Initial org save to generate objectId
        NSError *orgSaveError = nil;
        [self save:&orgSaveError];

        if (orgSaveError) {
            [errors addObject:@"Initial Org save Failed"];
        }

        // Create and Relate Org Contact
        NSError *saveOrgContactError = nil;
        MYontact *orgContact = [MYContact object];
        [orgContact setContactType:MYContactTypeUserOrganization];
        [orgContact setDisplayName:orgContactName];
        [orgContact setParentOrg:self];
        [orgContact save:&saveOrgContactError];

        if (saveOrgContactError) {
            [errors addObject:@"Saving Org Contact Failed"];
        } else {
            // If Org contact saved, set it;
            [self setOrgContact:orgContact];
        }

        // Create amd Relate User Contact
        NSError *saveUserContactError = nil;
        MYContact *userContact = [MYContact object];
        [userContact setFirstName:user.firstName];
        [userContact setLastName:user.lastName];
        [userContact setContactType:MYcontactTypeUser];
        [userContact setParentOrg:self];
        [userContact save:&saveUserContactError];

        if (saveUserContactError) {
            [errors addObject:@"Saving user contact failed"];
        }

        NSError *saveUserError = nil;
        [user setParentOrg:self];
        [user setUserContact:userContact];
        [user save:&saveUserError];

        if (saveUserError) {
            [errors addObject:@"Saving User failed"];
        }

        // Return if block succeeded and any errors.
        NSError *error = nil;
        BOOL succeeded;
        if (errors.count > 0) {

            NSDictionary *userInfo = @{@"error" : errors};
            errors = [NSError errorWithDomain:@"MyAppErrorDomain"
                                         code:1
                                     userInfo:userInfo];
            succeeded = NO;
        } else {
            succeeded = YES;
        }
        block(succeeded, error);
    });

}

@end