如何编写Objective-C完成块

我需要从我的视图控制器调用类方法,让它做它的事情,但然后只在类方法完成后执行一些操作.

(我认为我需要的是一个完成块,但如果我错了请纠正我.)

情况如下:

我正在使用Parse.com作为我的应用程序的后端.当用户注册帐户时,他们会在弹出窗口中输入他们的姓名,公司和其他信息,然后单击"提交".提交按钮链接到一个类方法(如下所示),该方法获取其PFUser对象和公司名称并创建一些数据库对象.函数完成后,使用委托解除弹出窗口.

问题是我需要按特定顺序创建这些对象,因为它们依赖于彼此对象的存在.问题是,在单击提交后立即调用解除弹出窗口的委托方法,因为它是堆栈中的下一个.

保存Parse对象时,会调用一个看起来像这样的方法:(这是我希望编写的,我认为可以解决我的问题)

[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:(与块有关的一切都是完全错误的我确定)

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];
}

如果您需要其他信息或说明,请与我们联系.

先感谢您!

---------编辑一个----------

好吧,以后几个相当大的时间单位,这就是我想出来的.整个实现可以更好地简化,并减少api调用,但会对此有所帮助.其他几个明显的问题也是第一步.

方法调用:

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

方法实施:

@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

CW0007007.. 82

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