Destroying custom scoped module

[sergejsha]

I have following use-case. I create a custom scope (@PerActivity) which creates a single module per Android Activity. Some instances in this module are initialized with Activity instance and has to be bound to Activity lifecycle. Particularly they have to receive onDestroy() call, when Activity gets destroyed.

Would it be possible to call some kind of close() or destroy() methods on the module that it forwards this call to all created instances interested in such a callback?

If not, is there Dagger2 API allowing me to write an extension doing this? Thanks!

[adipascu]

The modules are referenced inside a component, they are free to be GC-ed when the component is not referenced anymore.

[ronshapiro]

I think this is probably custom functionality that you'll want to have yourself. You can use ActivityLifecycleCallbacks which might be able to assist. I've tried to think of a couple solutions that involve providing an instance of that in the module, but none seem so clean to me since the Module doesn't know which dependencies were previously requested or not in a particular activity, which might lead to some instances being provided eagerly or unnecessarily on activity teardown. I think managing this yourself in onDestroy() is probably your best bet. Just how finalizers are considered harmful and unclear, it's good to be actively thinking about how your objects need to clean up when they're done being used. If GC is enough (like for most objects) then great, but if it's something that requires reclaiming resources/closing files/etc you probably want to be managing this.

[netdpb]

Closing, as this is a question that I don't think we can do anything to solve except to continue this conversation here or elsewhere.

[tir38]

Did anything ever come of this? I'm having the same questions now. I need to clean up some provided objects, not just have them be GC'd. I would really love a way for dagger to help me "release" objects. Dagger has changed a lot in the four years since this question was asked. Maybe something like this is now easier to implement. I just can't imagine more people don't have this issue.