Ensure the new state manager respects view visibility changes [164481490]

Fixed

Bug

Status Update

No update yet.

Description

jb...@google.com

created issue #1

Aug 14, 2020 07:56PM

When using the new state manager released in fragment 1.3.0-alpha08, if you manually (without using the hide/show fragment transactions) set the visibility state of your view after the SpecialEffectsController has started any animations/transitions on your view, the visibility changes are ignored.

The reason this happens is because the new state manager saves the visibility state of the view in onViewCreated() as the final state and then restores that visibility state once the special effect completes after onStart(). This means that any changes made by the user to the view visibility state between onViewCreate() and onStart() are completely ignored.

This becomes apparent in two particular cases:

There is a fragment that is always added, but has its visibility state updated based on some internal data (i.e. an error screen that is set to View.INVISIBLE when there is no error and View.VISIBLE when there is one). If the view state changes to INVISIBLE in onStart(), the fragment should not be shown once the add transaction completes.
A entering fragment is postponed and while it is postponed, its view visibility state is set to View.INVISIBLE. Even once the fragment is no longer postponed, its view should still be INVISIBLE until the user changes it again manually.

The new state manager should defer view visibility state control to the user no matter when the state is changed. Doing so would ensure that the user always has the source of truth for their Fragment's view visibility.

Comments

il...@google.com <il...@google.com> Aug 14, 2020 09:56PM

Assigned to jb...@google.com.

jb...@google.com <jb...@google.com> #2Aug 25, 2020 07:18PM

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

commit 92bd7222fcfd7523e8fa80b7f72e967b8bbf4750
Author: Ian Lake <ilake@google.com>
Date: Tue Aug 27 10:07:52 2019

Split LifecycleCallbacks from FragmentManager

Create a separate FragmentLifecycleCallbacksDispatcher
object that is responsible for dispatching
FragmentLifecycleCallbacks events.

Test: existing FragmentLifecycleTest pass
BUG: 139536619
Change-Id: I64cc2b364af65760b0008efb317a742df2c0718d

A fragment/fragment/src/main/java/androidx/fragment/app/FragmentLifecycleCallbacksDispatcher.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java

https://android-review.googlesource.com/1110155

https://goto.google.com/android-sha1/92bd7222fcfd7523e8fa80b7f72e967b8bbf4750

jb...@google.com <jb...@google.com> #3Aug 25, 2020 07:19PM

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

commit 092d14cd22c174405221b930665869f7c9fc8b65
Author: Ian Lake <ilake@google.com>
Date: Tue Aug 27 14:46:02 2019

Remove FragmentState mInstance

Make FragmentState a simple Parcelable by removing
its mInstance field and its instantiate() method.

This required we change the order of restoring:
instead of reconnecting retained Fragments with their
FragmentState instances, we first iterate through
all FragmentState instances and do one of two things:
1) Reconnect the retained fragment if it exists
2) Create a new fragment from the FragmentState

This allows us to do just one pass through our
FragmentState objects and run the edge case of
detecting retained fragments created after the
state was saved after creating the set of active
fragments.

Test: all existing tests pass
BUG: 139536619
Change-Id: Iba7cc300c127bc05127d122fa5acc1ccc871a76b

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManagerViewModel.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentState.java

https://android-review.googlesource.com/1108716

https://goto.google.com/android-sha1/092d14cd22c174405221b930665869f7c9fc8b65

ap...@google.com <ap...@google.com> #4Aug 26, 2020 06:55PM

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

commit 66d98b470d8887fdd16461c2da0df69ec62dd8d8
Author: Ian Lake <ilake@google.com>
Date: Fri Aug 16 13:22:20 2019

Add skeleton for FragmentStateManager

Store a HashMap of mWho to FragmentStateManager
instances. This serves as the minimal starting
point for moving logic that interacts with a
single Fragment from FragmentManager into
FragmentStateManager.

Test: existing tests pass, new FragmentStateManagerTest
BUG: 139536619
Change-Id: Ifaea272a3202e918143f65245fb98157ad971827

A fragment/fragment/src/androidTest/java/androidx/fragment/app/FragmentStateManagerTest.kt
M fragment/fragment/src/main/java/androidx/fragment/app/BackStackState.java
M fragment/fragment/src/main/java/androidx/fragment/app/Fragment.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
A fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java

https://android-review.googlesource.com/1109796

https://goto.google.com/android-sha1/66d98b470d8887fdd16461c2da0df69ec62dd8d8

il...@google.com <il...@google.com> #5Aug 28, 2020 12:17AM

Marked as fixed.

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

commit 92d322f39a3436da8ce0e59f55194c70abe1fb8e
Author: Ian Lake <ilake@google.com>
Date: Tue Aug 27 16:46:05 2019

Move saving/restore Fragment state to FragmentStateManager

Separate the saving and restoring of Fragment
instances from FragmentManager, allowing
FragmentStateManager to fully manage the
restoration of Fragments.

Test: new FragmentStateManagerTest, existing tests
BUG: 139536619
Change-Id: Iba0df8f617d7805995612eaad52e26f5f2e99707

M fragment/fragment/src/androidTest/java/androidx/fragment/app/FragmentStateManagerTest.kt
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java

https://android-review.googlesource.com/1109797

https://goto.google.com/android-sha1/92d322f39a3436da8ce0e59f55194c70abe1fb8e

Issue 164481490