Use Bundles for saving FragmentManager's hierarchical state [207158202]

Fixed

Bug

androidx-ui-starter-projects

Status Update

No update yet.

Description

il...@google.com

created issue #1

Nov 19, 2021 10:18PM

Component used: Fragment

Version used: 1.4.0

There are tools like toolargetool that let you explore what is taking up space in your saved instance state. However, it has no visibility into custom Parcelables like the FragmentManagerState used to store the entire FragmentManager's hierarchy of saved state.

This makes it hard to differentiate between the state of the FragmentManager itself and the state of each individual fragment, and, within a particular fragment, differentiating the view state, arguments, state provided by onSaveInstanceState(), and the fragment's SavedStateRegistry.

Therefore the focus should be on exposing the hierarchy of fragments - the bookkeeping associated with an individual Fragment and the FragmentManager specific state can and should remain as separate Parcelable instances that don't expose their internal fields.

Comments

il...@google.com <il...@google.com> Jan 11, 2022 08:56PM

Reassigned to sa...@google.com.

ap...@google.com <ap...@google.com> #2Apr 13, 2022 08:29PM

I am not sure I understand what you are asking for here.

The contract of onPrepareMenu in MenuProvider is:

"Called by the MenuHost right before the Menu is shown. This should be called when the menu has been dynamically updated."

If you were using Toolbar prior to the MenuHost integration, this should be a no-op for you. And if you are now switching to Toolbar, the onPrepareMenu() call should be in the proper place.

But the contract is not being violated.

If you are seeing some unexpected behavior, please provide a sample app that reproduces the error that you are observing.

ap...@google.com <ap...@google.com> #3Apr 13, 2022 09:20PM

reuploading my previous sample app.

It's fairly simple.

Call order with AppCompat 1.5.0-alpha01:

onCreateMenu
onPrepareMenu
user opens menu
menu is displayed

According to the contract:

"Called by the MenuHost right before the Menu is shown.

it should be:

onCreateMenu
user opens menu
onPrepareMenu
menu is displayed

build and run the sample. It has examples for both activity and fragment. Follow the print out's in the log.

ap...@google.com <ap...@google.com> #4Apr 21, 2022 09:55PM

Project: platform/frameworks/support
Branch: androidx-main

commit 723f2ef10ea1de61e94de16b917cc6e939bfc211
Author: Jeremy Woods <jbwoods@google.com>
Date: Tue Aug 02 17:05:42 2022

Fix Toolbar onPrepareMenu timing with MenuHost

Instead of unconditionally calling onPrepareMenu() when Toolbar executes
onCreateMenu(), it should wait until the menu is about to be shown to
make the call.

This will ensure that Toolbar properly fulfills the MenuHost contract.

RelNote: "Toolbar will now call `onPrepareMenu()` before the menu is shown
instead of unconditionally when the menu is created."
Test: modified the ToolbarMenuHostTest
Bug: 232206677

Change-Id: I2a58df0064c08b9ae87962a41d87e7bc60073df0

M appcompat/appcompat/src/main/java/androidx/appcompat/widget/Toolbar.java
M appcompat/appcompat/src/androidTest/java/androidx/appcompat/widget/ToolbarMenuHostTest.kt

https://android-review.googlesource.com/2172951

ap...@google.com <ap...@google.com> #5May 6, 2022 07:19PM

This has been fixed internally and will be available in the AppCompat 1.6.0-beta01 release.

ap...@google.com <ap...@google.com> #6May 19, 2022 08:32PM

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ap...@google.com <ap...@google.com> #7May 27, 2022 12:54AM

Delete all old

ap...@google.com <ap...@google.com> #8Jun 17, 2022 08:06AM

Project: platform/frameworks/support
Branch: androidx-main

commit 79febb5c150c47c99d52b8708775c49220195bbd
Author: Sanura N'Jaka <sanura@google.com>
Date: Wed Jun 08 04:24:21 2022

Have saveFragmentInstanceState return full state bundle

FragmentManager's saveFragmentInstanceState should
return the entire state bundle, not just the bundle
that was constructed in
FragmentStateManager.saveBasicState().

RelNote: "`FragmentManager`'s
`saveFragmentInstanceState` now returns the entire
state of the fragment, segmented, and not just
the bundle contructed during the fragment's
`onSaveInstanceState` callback."

Test: ran all tests in

androidx.fragment.app
Bug: 207158202
Change-Id: I1ffaf774b7fcaf45686379e9aebeeba1416ab61f

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentState.java
M fragment/fragment/src/main/java/androidx/fragment/app/Fragment.java

https://android-review.googlesource.com/2118765

jb...@google.com <jb...@google.com> Jun 17, 2022 04:59PM

Reassigned to jb...@google.com.

il...@google.com <il...@google.com> Jun 21, 2022 09:30PM

Reassigned to il...@google.com.

ap...@google.com <ap...@google.com> #9Jun 23, 2022 11:40PM

Project: platform/frameworks/support
Branch: androidx-main

commit 08ba745b9fda03c8a6c08b3f5abd4dbcdbf60ff5
Author: Ian Lake <ilake@google.com>
Date: Thu Jun 23 22:56:52 2022

Move target fragment into FragmentState

Co-locate the target fragment's unique identifier
and request code with other library state in the
FragmentState object.

Test: existing tests pass
BUG: 207158202
Change-Id: If7ee5d7729335b1ff3c2fa5d671d698d7aebb433

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentState.java

https://android-review.googlesource.com/2134685

ap...@google.com <ap...@google.com> #10Jun 24, 2022 05:47PM

Project: platform/frameworks/support
Branch: androidx-main

commit 775876606f25d109a6833503514834b428f7bb1e
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 00:05:17 2022

Move Fragment savedInstanceState out of FragmentState

Rather than FragmentState having a mix of
library state and user saved state (i.e., the state
returned by onSaveInstanceState()), these should be
stored independently from one another.

Test: existing tests pass
BUG: 207158202
Change-Id: If158c0e860aa7463252bc179673658b7696c3371

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentState.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/Fragment.java
M fragment/fragment/src/main/java/androidx/fragment/app/BackStackState.java

https://android-review.googlesource.com/2134687

ap...@google.com <ap...@google.com> #11Jun 24, 2022 05:47PM

Project: platform/frameworks/support
Branch: androidx-main

commit bf62dd252aae22511da44fc8bb4975e57abedfa3
Author: Ian Lake <ilake@google.com>
Date: Thu Jun 23 23:07:37 2022

Move user visible hint into FragmentState

Co-locate the userVisibleHint flag with the
other library state in the FragmentState object.

Test: existing tests pass
BUG: 207158202
Change-Id: I8bdd5ee138aa1d6505df9e806635eb78bca69729

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentState.java

https://android-review.googlesource.com/2134686

ap...@google.com <ap...@google.com> #12Jun 24, 2022 07:01PM

Project: platform/frameworks/support
Branch: androidx-main

commit 1deb87b58f32ad191ba066ab5d48740d45c95464
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 17:53:01 2022

Move Fragment View State out of savedInstanceState Bundle

Rather than include the Fragment's SparseArray<Parcelable>
of its view's state or the Fragment View's SavedStateRegistry
bundle as part of the Bundle returned by onSaveInstanceState,
store those as separate values in the Fragment's
saved state Bundle.

Test: existing tests pass
BUG: 207158202
Change-Id: I3abfc7db186e6a921b00193fff27c62199687976

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java

https://android-review.googlesource.com/2135874

ap...@google.com <ap...@google.com> #13Jun 25, 2022 12:20AM

Project: platform/frameworks/support
Branch: androidx-main

commit 8a019327ad267d6251167e400ea79cb8a54243b3
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 20:53:15 2022

Move childFragmentManager state out of savedInstanceState

Migrate the childFragmentManager state out of the same
Bundle as is passed to onSaveInstanceState(). Instead,
store that Bundle as a separate value in the Fragment's
saved state Bundle.

Test: existing tests pass
BUG: 207158202
Change-Id: I456259053dfc833d39c4f648e23735b98cb65714

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/Fragment.java

https://android-review.googlesource.com/2135877

ap...@google.com <ap...@google.com> #14Jun 25, 2022 12:21AM

Project: platform/frameworks/support
Branch: androidx-main

commit 3ccf9b6e609c6f2130689bb2f8c4bff6e2907df3
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 21:38:19 2022

Use all initial state when saving an initializing fragment

With the state split across multiple fields, saving the
state of an Fragment still in the INITIALIZING state should
use the entire saved state Bundle set by
setInitialSavedState() rather than only extracting the
onSaveInstanceState() bundle out of it.

Test: existing tests pass
BUG: 207158202
Change-Id: I95868473b28b179d7cc0b0e606427928982dc96c

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java

https://android-review.googlesource.com/2135880

ap...@google.com <ap...@google.com> #15Jun 25, 2022 12:21AM

Project: platform/frameworks/support
Branch: androidx-main

commit f7ec0cc1786b4a16c0569cc07ecf5093693bcab0
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 21:30:15 2022

Skip empty/null keys when saving Fragment state

Each key in the Fragment's saved state Bundle takes up
space in the limited resource that is the total
saved instance state. By removing empty or null keys,
we can ensure that the set of saved key/values is
minimized.

Test: existing tests pass
BUG: 207158202
Change-Id: I4e0f4772982406bfe10e64d78d26e93f4e2bc387

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java

https://android-review.googlesource.com/2135879

ap...@google.com <ap...@google.com> #16Jun 25, 2022 12:21AM

Project: platform/frameworks/support
Branch: androidx-main

commit 5cc7478b61c2f48452770285d7ba8c74be907b19
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 21:18:57 2022

Move SavedStateRegistry state out of savedInstanceState

Migrate the SavedStateRegistry's state out of the same
Bundle as is passed to onSaveInstanceState(). Instead,
store that Bundle as a separate value in the Fragment's
saved state Bundle.

Test: existing tests pass
BUG: 207158202
Change-Id: I903d56901e6c5a5caf2890a4dbe5471c73169b56

M fragment/fragment/src/main/java/androidx/fragment/app/FragmentStateManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
M fragment/fragment/src/main/java/androidx/fragment/app/Fragment.java

https://android-review.googlesource.com/2135878

ap...@google.com <ap...@google.com> #17Jun 25, 2022 12:40AM

Project: platform/frameworks/support
Branch: androidx-main

commit 28e7a78343af524c7854a3f951809448a8457dd1
Author: Ian Lake <ilake@google.com>
Date: Fri Jun 24 21:58:43 2022

Move and rename _TAG constants to _KEY

Rename all constants used as Bundle keys to use
the _KEY suffix rather than _TAG to prevent mistaking
them for debug tags.

Also moves all keys associated with the Fragment's state
into FragmentStateManager, which is responsible for
saving the Fragment's state. Keys associated with saving
the FragmentManager's state are still in FragmentManager.

Test: existing tests pass
BUG: 207158202
Change-Id: I6e47a4a0ec84c708f9a3c984e737ed7314530156

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

https://android-review.googlesource.com/2135883

il...@google.com <il...@google.com> #18Jun 27, 2022 11:46PM

Marked as fixed.

The saved state of Fragments has been split entirely between private library state (custom Parcelable classes) and state provided by you, the developer, which is now always stored in a Bundle that allows determining exactly which part of the fragment's state is too large.

The final structure is as follows:

In the Activity's onSaveInstanceState, the "android:support:fragments" key now contains a Bundle that contains the following information:

"state" - the private Parcelable storing the FragmentManager's saved state (e.g., the fragment back stack info)
For each Fragment Result that has been set via setFragmentResult but has not yet been delivered: "result_$name" -> (user defined Bundle)
For each Fragment (where the fragment_id matches the UUIDs found in the debug logging): "fragment_$fragment_id" -> Bundle
- "state" -> the private Parcelable storing the Fragment's saved state (e.g., the class name, max lifecycle, etc.)
- "arguments" -> (Bundle of arguments)
- "savedInstanceState" -> (onSaveInstanceState filled Bundle)
- "registryState" -> (SavedStateRegistry filled Bundle)
- "childFragmentManager" -> The “android:support:fragments” equivalent Bundle of the child FragmentManager, which would lead us recursively down the tree
- "viewState" -> the SparseArray<Parcelable> returned by View.saveHierarchyState representing the Fragment View state
- "viewRegistryState" -> (View SavedStateRegistry filled Bundle)

This will be fully available in Fragment 1.6.0-alpha01.