SavedStateRegistryOwner should describe the implementing classes' responsibilities [228887344]

Fixed

Bug

Status Update

No update yet.

Description

il...@google.com

created issue #1

Apr 11, 2022 10:47PM

Component used: SavedState

Version used: 1.2.0-alpha02

The docs on SavedStateRegistryOwner do not explain the responsibilities and contract that the owner has on how they should implement SavedStateRegistryOwner or when they should call the methods on SavedStateRegistryController.

Ideally the class docs should talk through:

That performAttach() should be called only once, usually as part of the initialization of the owner. It must be called on the main thread.
That performRestore should be called unconditionally (either with null if no state is being restored or the Bundle of state to restore) either directly before moving the Lifecycle to CREATED or as part of a LifecycleObserver that is added as part of the initialization of the owner.
When the state of the owner is saved, performSave() must be called. The Bundle saved there should be what is later sent to performRestore().

Comments

il...@google.com <il...@google.com> Apr 14, 2022 04:58PM

Assigned to cl...@google.com.

cl...@google.com <cl...@google.com> Apr 14, 2022 04:59PM

Accepted by cl...@google.com.

ap...@google.com <ap...@google.com> #2Apr 19, 2022 10:44PM

Marked as fixed.

Looks to be the same issue as

https://github.com/androidannotations/androidannotations/issues/1208 where after being parceled and unparceled, the type swaps to Parcelable[] which is indeed a different type than CustomModel[]. The same thing can be seen with Fragment destinations if you:
1. turn on the Developer Option of "Don't keep activities"
2. Navigate to the Fragment destination (it won't crash)
3. Hit the home button
4. Use the recents button to relaunch the app (it will crash)

It seems like the only viable work around is to create a new array of the correct type (CustomModel[]), then System.arraycopy() the objects over. We can do this automatically as part of the Args class. We should also double check to see if this same problem exists with Serializable.

le...@gmail.com <le...@gmail.com> #3Oct 21, 2022 02:20AM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 72631a760ebfb23990c42440d0c1f8c67fafe5ed
Author: Daniel Santiago Rivera <danysantiago@google.com>
Date: Thu Feb 07 14:11:06 2019

Copy & Cast Parcelable array items when reading NavArgs from Bundle

Bundle#getParcelableArray() return Parcelable[] which NavArgs was
failing to cast to Item[] where Item is an app defined Parcelable. This
CL changes the generated code so that the Parcelable[] items are copied
into an array of the defined type in the nav graph.

This issue doesn't exist for Serializable since there is no
Bundle#getSerializableArray().

Bug: 123963545
Test: Manual test with sample app provided in issue.
Change-Id: Ibfcb703a1ad48929a0731b82a13a1f33813187b5

M navigation/safe-args-generator/src/main/kotlin/androidx/navigation/safe/args/generator/java/JavaTypes.kt
M navigation/safe-args-generator/src/main/kotlin/androidx/navigation/safe/args/generator/kotlin/KotlinTypes.kt
M navigation/safe-args-generator/src/tests/test-data/expected/java_nav_writer_test/MainFragmentArgs.java
M navigation/safe-args-generator/src/tests/test-data/expected/kotlin_nav_writer_test/MainFragmentArgs.kt

https://android-review.googlesource.com/898454

https://goto.google.com/android-sha1/72631a760ebfb23990c42440d0c1f8c67fafe5ed

le...@gmail.com <le...@gmail.com> #4Oct 21, 2022 02:21AM

This is fixed internally and will be available in Navigation 1.0.0-beta02

le...@gmail.com <le...@gmail.com> #5Oct 21, 2022 02:22AM

Something like mono

le...@gmail.com <le...@gmail.com> #6Oct 21, 2022 02:22AM

AB+ blood type