Update documentation for dagger-android in order to show how to use custom scopes

[roshakorost]

In Android world most apps have authorization. Dagger helps with that a lot, as it allows to create custom subcopoments/scopes for authorized user.

The following setup is very usedfull for me:

• ApplicationScope and AplicationComponent - the root compontent with some basic AndroidDependecies.
• NonAuthorizedScope and corresponding component, which is used accross login, sign up and screens that doesn't need authorization.
• AuthorizedScope and its compoent, which is created after login and is kept untill logout. It is very helpfull for storing access token and some user preferences.
• And some per screen components, which are usually unscoped.

For long time I thought that such setup is not possible to achieve by dagger-android. The documentation suggests that you should have application component and subcomponents per activity and per fragment.
However, I just found ssue #1267 which has suggestions how to organize simmialr component hirereachy and how to use it with dagger-android.

It would be wonderfull to update the documentation with such example. Also example app will be helpfull a lot.

[roshakorost]

I created sample app how to use custom scopes with dagger-android https://github.com/roshakorost/Dagger-Android-Cookbook/tree/master/customscopes

The overall aproach is very simple, basically you should detect what component to use in your application.
@ContributesAndroidInjector works normally with subcomponents.

I am going to create severall small projects with varios injection stuff, related to dagger android. Please, create issues in case you want something to see.

[damirmiljkovic]

Is it possible to have two fragments with different scopes in same activity(which is in same scope as one of the fragments). I asked this question on stackoverflow(https://stackoverflow.com/questions/53761310/dagger-2-fragments-with-different-scope)

[rcmkt]

@roshakorost Thanks a lot for sharing the example :)
I thought that's impossible as well. In the meantime, can I use dagger-android and custom scopes using relatives between components like this:

@Component(
        dependencies = [ApplicationProvider::class]
)

instead of Subcomponent?

[Chang-Eric]

I'm going to close this because dagger-android isn't really being developed now that Hilt is released. While we are still keeping dagger-android maintained, I think this topic is probably complex enough that it would be a fair amount of documentation to write that unfortunately would be a fairly large amount of work.