{"id":2631,"date":"2018-04-20T17:28:30","date_gmt":"2018-04-20T13:28:30","guid":{"rendered":"https:\/\/blog.alwawee.ru\/?p=2631"},"modified":"2018-04-20T17:32:06","modified_gmt":"2018-04-20T13:32:06","slug":"using-raccommand-and-creating-custom-racsignals-in-objective-c","status":"publish","type":"post","link":"https:\/\/blog.alwawee.ru\/?p=2631","title":{"rendered":"Using RACCommand and creating custom RACSignals in Objective C"},"content":{"rendered":"

To bind some action to the button click one can use just a custom RACSignal. But then you have to add three more things in every case:
\n1. Disable button, while action is performing;
\n2. Show, that action is in progress;
\n3. Disable button, if input is incorrect and button should not be able to be tapped. <\/p>\n

Instead, if you use RACCommand, you get all these things in a box. <\/p>\n

Let’s say, we want to bind RACCommand verifyPhoneCommand to a button. We can create a command in a lazy property in a ViewModel: <\/p>\n

\r\n- (RACCommand *)verifyPhoneCommand\r\n{\r\n    if (! _verifyPhoneCommand) {\r\n        _verifyPhoneCommand = [[RACCommand alloc] initWithEnabled:self.phoneValidSignal\r\n                                                      signalBlock:^RACSignal * _Nonnull(id  _Nullable input) {\r\n                                                          return [self verifyPhone];\r\n                                                      }];\r\n    }\r\n    return _verifyPhoneCommand;\r\n}\r\n<\/pre>\n
Here phoneValidSignal is this signal, that is formed by observing a phone variable: <\/p>\n
\r\n- (RACSignal *)phoneValidSignal\r\n{\r\n    if (!_phoneValidSignal) {\r\n        _phoneValidSignal = [RACObserve(self, phone) map:^id(NSString *phone) {\r\n            return @(phone.length > 0);\r\n        }];\r\n    }\r\n    return _phoneValidSignal;\r\n}\r\n<\/pre>\n
We pass a RACSignal verifyPhone to the RACCommand to do a job: <\/p>\n
\r\n- (RACSignal *)verifyPhone\r\n{\r\n    return [RACSignal createSignal:^RACDisposable * _Nullable(id  _Nonnull subscriber) {\r\n\r\n        [[PhoneManager sharedManager]\r\n         requestVerifyPhone:self.phone\r\n         success:^{\r\n\r\n             [subscriber sendNext:@(YES)];\r\n             [subscriber sendCompleted];\r\n             \r\n         } failure:^(NSError *error) {\r\n             \r\n             [subscriber sendError:error];\r\n             \r\n         }];\r\n        \r\n        return nil;\r\n    }];\r\n}\r\n<\/pre>\n
This is how we bind a RACCommand to a button: <\/p>\n
\r\nself.smsRequestButton.rac_command = self.viewModel.verifyPhoneCommand;\r\n<\/pre>\n
To track execution of a RACCommand and show an activity indicator we can use executing property: <\/p>\n
\r\n[self.viewModel.verifyPhoneCommand.executing subscribeNext:^(NSNumber*  _Nullable x) {\r\n        if (x.boolValue) {\r\n            [self.spinnerView startAnimating];\r\n        }\r\n        else {\r\n            [self.spinnerView stopAnimating];\r\n        }\r\n    }];\r\n<\/pre>\n
If errors happen during RACCommand execution we can process those errors: <\/p>\n
\r\n[self.viewModel.verifyPhoneCommand.errors subscribeNext:^(NSError * _Nullable error) {\r\n        [ErrorUtil showError:error from:self onRepeat:^{\r\n            \r\n        }];\r\n    }];\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
To bind some action to the button click one can use just a custom RACSignal. But then you have to add three more things in every case: 1. Disable button, while action is performing; 2. Show, that action is in progress; 3. Disable button, if input is incorrect and button should not be able to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[206,205,194],"class_list":["post-2631","post","type-post","status-publish","format-standard","hentry","category-ios","tag-objective-c","tag-raccommand","tag-reactivecocoa"],"yoast_head":"\nUsing RACCommand and creating custom RACSignals in Objective C - Denis Kutlubaev<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.alwawee.ru\/?p=2631\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Using RACCommand and creating custom RACSignals in Objective C - Denis Kutlubaev\" \/>\n<meta property=\"og:description\" content=\"To bind some action to the button click one can use just a custom RACSignal. But then you have to add three more things in every case: 1. Disable button, while action is performing; 2. Show, that action is in progress; 3. 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