I'm using 5 beta, trying to make retainedKodein wo...

# kodein

[mate.herber]

I'm using 5 beta, trying to make retainedKodein work but it crashes for me:

Caused by: java.lang.IllegalStateException: Fragment org.kodein.android.KodeinFragment must be a public static class to be  properly recreated from instance state.
        at android.app.BackStackRecord.doAddOp(BackStackRecord.java:429)
        at android.app.BackStackRecord.add(BackStackRecord.java:409)
        at org.kodein.android.RetainedKt$retainedKodein$1.invoke(retained.kt:26)
        at org.kodein.android.RetainedKt$retainedKodein$1.invoke(Unknown Source:0)
        at kotlin.SynchronizedLazyImpl.getValue(Lazy.kt:131)
...

[mate.herber]

anybody experienced the same?

[mate.herber]

setting fragment to public seems to solve

[mate.herber]

or not, if I copy the retained.kt to my project it works even with private

[streetsofboston]

I’m surprised you can even build/compile it.
KodeinFragment is a private final class when looking at the kodein-framework-android dependency contents

This means you can’t instantiate nor subclass from it.

And every Android concrete Fragment must be public and have a public empty/default constructor.

[mate.herber]

https://github.com/SalomonBrys/Kodein/blob/5.0/framework/kodein-framework-android/src/main/java/org/kodein/android/retained.kt

[mate.herber]

nah I'm stupid

[streetsofboston]

Ah.... it is created privately by a factory (Activity.retainedKodein). Still, a concrete fragment must have a public empty/default constructor. If not, your app will crash when a configuration change (e.g rotation of the phone) happens. This seems to be a bug in Kodein. @salomonbrys Is this a bug?

[mate.herber]

retainedKodein is just a shortcut for having a simple kodein with everything scoped with activityRetainedScope right?

[salomonbrys]

@streetsofboston This is very weird. KodeinFragment is supposed to be registered as a retained fragment. So it should not be recreated by the system as it should be preserved between config changes.

[salomonbrys]

OK, so this is a Kodein Bug, thanks a lot for reporting it

[salomonbrys]

Whether it is a retained fragment or not, Android will complain if the fragment's class dpes not conforms to standard fragments form (from Nougat and over) as the code clearly shows here : https://github.com/aosp-mirror/platform_frameworks_base/blob/master/core/java/android/app/BackStackRecord.java#L429

[streetsofboston]

Yep. In short, the creation of Fragments is up to the Android Framework and when you try to fight that, you’ll get into trouble 🙂
To be sure the Android Framework can do this, Fragments must have public empty/default constructors.

Note that the Fragment may not be retained and the Android Framework creates a new one on a configuration change. To make sure it is retained between config changes, call setRetainInstance(true) on the Fragment

[salomonbrys]

Of course I do : https://github.com/SalomonBrys/Kodein/blob/5.0/framework/kodein-framework-android/src/main/java/org/kodein/android/retained.kt#L15

[salomonbrys]

😉

[streetsofboston]

Hah…. yep, you did set that retain-instance to true. And still, the platform likes to create one after a rotation… weird. I guess it is just pro-active in ‘warning’ you about not having a public default constructor 🙂

[salomonbrys]

AFAIU, the platform will not recreate it (because setRetainInstance(true)), but it does still check the conformity 😞

[streetsofboston]

I guess it does that in case the app needs to be restored after its process has being killed when it was in the background.

[salomonbrys]

...didn't think about that 😉