rac_command only responds to single click - ios

Question

I am trying to detect clicks on an UIElement like a button using Reactive Cocoa, using RAC for the first time in MVVM architecture.
I set the rac_command for my button in my ViewController.
addContactBtn.rac_command = viewModel.addContact
My ViewModel does the following:
func init(){
self.addContact = RACCommand() {
(any:AnyObject!) -> RACSignal in
return RACSignal.createSignal({
(subscriber: RACSubscriber!) -> RACDisposable! in
print("creating viewModel")
let viewModel = ContactAddViewModel(services: self.services)
self.services.pushViewModel(viewModel)
return RACDisposable(block: {
})
})
}
}
However, the command is executed only once and then the button is in disabled state when I pop the view controller and come back to original viewController. How can detect the button click any number of times?

Answer 1

Obviously, you missed something and had a simple mistake.
RACCommand expects to a signal which will be alive when the button clicked and be disposed after click-business-logic (like create viewModel, then pushViewModel in the above) executed. That is to say each button clicking-event associates a signal, not shares one unique signal, but has common signal inner logic. If a signal does not achieve completion or error, the responding clicking-event is not finished such that the button is disabled.
The below modified codes could be correct.
func init(){
self.addContact = RACCommand() {
(any:AnyObject!) -> RACSignal in
return RACSignal.createSignal({
(subscriber: RACSubscriber!) -> RACDisposable! in
print("creating viewModel")
let viewModel = ContactAddViewModel(services: self.services)
self.services.pushViewModel(viewModel)
// if you like to expose some value
// subscriber.sendNext(value)
subscriber.sendCompleted() // which makes clicking-event finished
// maybe error occurs
// subscriber.sendError()
return RACDisposable(block: {
})
})
}
}
I would like to advise you to checkout CocoaAction and Action in ReactiveSwift, which are replacement for RACCommand of legacy ReactiveObjC.