Dagger2 Provider in koin

Question

Is there any alternative to javax.inject.Provider in koin?

To react to actions, I am injecting Commands to my activity. Command is a single-run object, for example WriteToFile.

In dagger I could make it like this:

class MainPresenter : Presenter() {

  @Inject
  lateinit var writeFile: Provider<WriteFileCommand>

  fun onSaveClicked() {
    writeFile.get().run()
  }
}

in koin, when I try to use:

class MainPresenter : Presenter() {

  lateinit var writeFile: Provider<WriteFileCommand> by inject()

  fun onSaveClicked() {
    writeFile.get().run()
  }
}

My koin module:

val appModule = module {
  factory { WriteFileCommand(get(), get()) }
  factory { FileProvider() }
  single { DataStore() }
}

Than I got error saying:

Can't create definition for 'Factory [name='WriteFileCommand',class='com.test.WriteFileCommand']' due to error : No compatible definition found. Check your module definition

I understand that I can call:

var command: WriteFileCommand = StandAloneContext.getKoin().koinContext.get()
command.run()

But It looks so cumbersome

Answer 1

There's nothing like a provider directly. If you use inject, you'll use a lazy delegate. If you use get, you'll create a new instance you declared the dependency with a factory. So get is what you need in your case. Just let your MainPresenter implement KoinComponent and you'll be able to use get directly:

class MainPresenter : Presenter(), KoinCompontent {
  fun onSaveClicked() = get<WriteFileCommand>().run()
}