Problems w/ Android 4.x

[brianegan]

Hello! Trying to get Injekt going with a test project of mine, and running into trouble. It works great on Lollipop+, but on Android 4.x I'm running into trouble.

The error I'm seeing:

java.lang.RuntimeException: Unable to instantiate application com.brianegan.bansa.counter.Application: uy.kohesive.injekt.api.InjektionException: No registered instance or factory for type com.brianegan.bansa.Store<com.brianegan.bansa.counter.ApplicationState, com.brianegan.bansa.Action>
    at android.app.LoadedApk.makeApplication(LoadedApk.java:526)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4390)
    at android.app.ActivityThread.access$1500(ActivityThread.java:139)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1260)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5105)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: uy.kohesive.injekt.api.InjektionException: No registered instance or factory for type com.brianegan.bansa.Store<com.brianegan.bansa.counter.ApplicationState, com.brianegan.bansa.Action>
    at uy.kohesive.injekt.registry.default.DefaultRegistrar.getInstance(DefaultRegistrar.kt:99)
    at uy.kohesive.injekt.api.InjektScope.getInstance(Scope.kt)
    at com.brianegan.bansa.counter.Application.<init>(Application.kt:30)
    at java.lang.Class.newInstanceImpl(Native Method)
    at java.lang.Class.newInstance(Class.java:1208)
    at android.app.Instrumentation.newApplication(Instrumentation.java:990)
    at android.app.Instrumentation.newApplication(Instrumentation.java:975)
    at android.app.LoadedApk.makeApplication(LoadedApk.java:521)
    ... 11 more

My code can be found here:
https://github.com/brianegan/bansa/blob/master/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/Application.kt

I also tried Injekting a module in onCreate instead of using a companion object, with no luck. Feeling like a bit of a n00b here though, trying to figure out what I'm doing wrong! Any advice would be much appreciated :)

[apatrida]

Hi, first a note on your code:

 val store = Injekt.get(fullType<Store<ApplicationState, Any>>())

should simply be a delegate when used as a property:

 val store: Store<ApplicationState, Any> by injectLazy() // or injectValue()

Or can be assigned:

 val store: Store<ApplicationState, Any> = Injekt.get()

and in the injekt registration:

 addSingleton(
                    fullType<Store<ApplicationState, Any>>(),
                    createStore(ApplicationState(), counterReducer));

can be:

  addSingleton<Store<ApplicationState, Any>>(createStore(ApplicationState(), counterReducer))

Or if the return type of createStore is already Store<ApplicationState, Any> then just:

 addSingleton(createStore(ApplicationState(), counterReducer))

No need to use fullType anywhere. Reified generics will take care of this. If you cannot get the IDE to show the correct extension function, then import:

import uy.kohesive.injekt.api.*
import uy.kohesive.injekt.*

temporarily until you have everything in use and happy.

This shouldn't be your problem though unless the newer version of Android is causing the instance to be created without loading the reference to the companion object. With some magic in their VM they could do this, although evil it is possible.

If you only have one application instance anyway, just change it to a member as well:

val injektMain = object : InjektMain() {
        override fun InjektRegistrar.registerInjectables() {
            // ...
        }
    }

It is a small change and will make sure all registrations are done since members are instantiated and initialized in the order they appear top to bottom. Let me know if this helps.

[brianegan]

Great, thanks for the tips! I tried a couple of similar patterns, but not this exact one. I'll give it a shot tonight :)

[apatrida]

How did this work out?

[brianegan]

Hey there! Sorry about the delay -- busy times from my side. Thanks so much again for the help. I made some time tonight to play around with it. Here my findings:

Good call on the code cleanup -- addSingleton and by injectLazy() are really cool improvements.

With regards to Android 4.x, I tried a few things.

Attempt 1 - InjektMain() becomes a field

I tried your suggestion of assigning the InjektMain object to a field in the Application class. Unfortunately, I ran into the same error as described in my original post. You can see this code here:

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-1/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/Application.kt

Attempt 2 - Move val store to onCreate

A slight variation on Attempt #1 -- I've simply moved the val store from a class field into the onCreate function to delay the access even further. This also didn't work. Same error.

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-2/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/Application.kt

Attempt 3 - importModule

A combination of #1, #2 and now I've introduced a StoreModule : InjektModule class and tried injecting that. This didn't work either :(

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-3/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/Application.kt

Attempt 4 - Don't inject in the application class

This isn't my favorite solution as someone might need to both register and then use a module inside the application init phase, but I wanted to give it a shot. I simply move the injection out of the Application class and into the RootActivity. Unfortunately, this also didn't work :(

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-4/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/Application.kt

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-4/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/RootActivity.kt

Attempt 5 - No Injekt (Control)

As a sanity check, I removed Injekt and the app worked on Android 4.x.

https://github.com/brianegan/bansa/blob/injekt-android-4.x-fix-5/examples/counter/src/main/kotlin/com/brianegan/bansa/counter/RootActivity.kt

Thanks again for helping me track this down! This is such a cool project, I hope we can get it working on Android 4.x.

Hopefully these branches will provide some helpful code samples. If I get a bit more time, I'll try to dig into the root of the problem.

[brianegan]

Another attempt: Tried injecting a basic Kotlin type String into the root activity and that worked... Not sure what it is about my types that work on Android 5+ vs 4.x :(

[apatrida]

can you add logging to see the order of operations, log inside the injekt registration, log inside your onCreate method. Is OnCreate called from the ancestor constructor? or is it called later?

[brianegan]

Sure, I also stepped through the app, and it runs through in this order (which seemed correct to me):

1. injektMain field is created, runs registerInjectables
2. registerInjectables runs importModule(StoreModule())
3. StoreModule#registerInjectables runs, executing the addSingleton<Store<ApplicationState, Any>>
4. Application#onCreate is called
5. RootActivity#onCreate is called, runs Injekt.get<Store<ApplicationState, Any>>()
6. App Crash with error message above

[apatrida]

1. the error must be different because you are asking for Any instead of Action as the second generic parameter. Can I see the current error with latest attempt?

[apatrida]

also can you try it as a addSingletonFactory and pass a lambda where you cast it to Any if you are going to do that cast.

 override fun InjektRegistrar.registerInjectables() {
            addSingletonFactory { 
                  createStore(ApplicationState(), counterReducer) as Store<ApplicationState, Any>
            }
        }

The compiler should give you warnings about this cast, or say it isn't needed, or something, I'd like to see what it tells you.

Also if you debug, you can look at the injekt registry and see what type is stored in the lookup hashmap which will also give a clue.

[apatrida]

I can mock these out and see if there is a problem with generics somewhere, but I've never seen one.

[brianegan]

Ah, sorry -- that error message above is slightly out of date as this library I'm working on has moved from Action to Any. The error is essentially the same (this is after moving all injection out of the app and into the activity):

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.brianegan.bansa.counter/com.brianegan.bansa.counter.RootActivity}: uy.kohesive.injekt.api.InjektionException: No registered instance or factory for type com.brianegan.bansa.Store<com.brianegan.bansa.counter.ApplicationState, java.lang.Object>

I'll give it a quick shot as a singletonFactory instead. Thanks again for your help debugging this!

I also think the types are correct overall, as it is working in Android 5+ -- I'm not sure if there's something unique to the 4.x environment?

[brianegan]

"Also if you debug, you can look at the injekt registry and see what type is stored in the lookup hashmap which will also give a clue."

Ah, cool -- I'll try this as well to see if it's a weird type mismatch! Thanks again.

[brianegan]

"The compiler should give you warnings about this cast, or say it isn't needed, or something, I'd like to see what it tells you."

Compiler: "No cast needed"

[apatrida]

I'm writing a test case now. Back in a bit with results, maybe something happens when two generics are present.

[brianegan]

Cool, Thanks!