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android / platform / frameworks / support / f958564f327d27b02f262d56fa3ebb29fd04ad05
commitf958564f327d27b02f262d56fa3ebb29fd04ad05[log] [tgz]
authorDustin Lam <dustinlam@google.com>Fri Aug 27 17:10:23 2021 -0700
committerDustin Lam <dustinlam@google.com>Tue Sep 21 09:49:28 2021 -0700
treea3e3fe212ed6684c6676918695692814a96e7a2e
parent15c82ee9ef29e6bb396010bd4b8b4e3a051aaf99 [diff]
Do not track remote states locally within PageFetcher for PageEvents

Previously from fetcher side, we locally tracked remote load states
per-generation to inject them into the page event stream, however this
leads to issues between generations, where the local state is incorrect
before it receives an event from either the source or remote stream.

This CL changes .injectRemoteEvents into a custom .combine operator so
that we always wait for a real event from both remote and source flows,
so that we are guaranteed to have valid states for both. We also now
immediately send REFRESH=Loading from source so that it is less likely
to drop remote events due to waiting on source flow from .combine.

The reason we use a custom .combine operator is to remove the "batching"
logic in .combine, which would normally output the latest values from
each Flow and can miss emissiosn when we get multiple emissions on the
same Flow, as opposed to alternating emissions.

Since it also affected some tests, this CL also fixes a longstanding
issue with cancellation on invalidation. Previously, a collector
would continue to receive remote events after invalidation, which
can make it difficult for Java users or those not using collectLatest to
switch to the next generation, since submitData would never return until
cancelled. We now eagerly cancel collection on the remote stream (within
a generation) to close the Flow<PageEvent> from a PagingData as soon as
we receive a new generation.

RelNote: "LoadStates from Paging now await valid values from both
  PagingSource and RemoteMediator before emitting downstream between
  generations. This prevents new generations of PagingData from sending
  NotLoading in CombinedLoadStates.source.refresh if it was already
  Loading; new generations of PagingData will now always correctly begin
  with Loading for refresh state instead of first resetting to NotLoading
  incorrectly in some cases.

  Cancellation on past generations now happen eagerly on invalidation /
  new generations. It should no longer be required to use .collectLatest
  on Flow<PagingData>, although it is still highly recommended to do so."

Fixes: 177351336
Fixes: 195028524
Test: ./gradlew paging:paging-common:test
Change-Id: I0b2b5e0120e2e3a677f65d40d3955a9bbbe2e1a9
11 files changed
tree: a3e3fe212ed6684c6676918695692814a96e7a2e
  1. .github/
  2. .idea/
  3. activity/
  4. ads/
  5. annotation/
  6. appcompat/
  7. appsearch/
  8. arch/
  9. asynclayoutinflater/
  10. autofill/
  11. benchmark/
  12. biometric/
  13. browser/
  14. buildSrc/
  15. buildSrc-tests/
  16. busytown/
  17. camera/
  18. car/
  19. cardview/
  20. collection/
  21. collection2/
  22. compose/
  23. concurrent/
  24. contentpager/
  25. coordinatorlayout/
  26. core/
  27. cursoradapter/
  28. customview/
  29. datastore/
  30. development/
  31. docs/
  32. docs-public/
  33. docs-tip-of-tree/
  34. documentfile/
  35. draganddrop/
  36. drawerlayout/
  37. dynamicanimation/
  38. emoji/
  39. emoji2/
  40. enterprise/
  41. exifinterface/
  42. external/
  43. fakeannotations/
  44. fragment/
  45. frameworks/
  46. glance/
  47. gradle/
  48. gridlayout/
  49. health/
  50. heifwriter/
  51. hilt/
  52. inspection/
  53. interpolator/
  54. jetifier/
  55. leanback/
  56. lifecycle/
  57. lint-checks/
  58. lint-demos/
  59. loader/
  60. localbroadcastmanager/
  61. media/
  62. media2/
  63. mediarouter/
  64. navigation/
  65. paging/
  66. palette/
  67. percentlayout/
  68. placeholder-tests/
  69. playground-common/
  70. preference/
  71. print/
  72. profileinstaller/
  73. recommendation/
  74. recyclerview/
  75. remotecallback/
  76. resourceinspection/
  77. room/
  78. samples/
  79. savedstate/
  80. security/
  81. sharetarget/
  82. slice/
  83. slidingpanelayout/
  84. sqlite/
  85. startup/
  86. swiperefreshlayout/
  87. test/
  88. testutils/
  89. text/
  90. textclassifier/
  91. tracing/
  92. transition/
  93. tvprovider/
  94. vectordrawable/
  95. versionedparcelable/
  96. viewpager/
  97. viewpager2/
  98. wear/
  99. webkit/
  100. window/
  101. work/
  102. .gitignore
  103. .mailmap
  104. build.gradle
  105. cleanBuild.sh
  106. code-review.md
  107. CONTRIBUTING.md
  108. gradle.properties
  109. gradlew
  110. include-composite-deps.gradle
  111. include-support-library.gradle
  112. LICENSE.txt
  113. OWNERS
  114. PREUPLOAD.cfg
  115. README.md
  116. settings.gradle
  117. studiow
README.md

Android Jetpack

Jetpack is a suite of libraries, tools, and guidance to help developers write high-quality apps easier. These components help you follow best practices, free you from writing boilerplate code, and simplify complex tasks, so you can focus on the code you care about.

Jetpack comprises the androidx.* package libraries, unbundled from the platform APIs. This means that it offers backward compatibility and is updated more frequently than the Android platform, making sure you always have access to the latest and greatest versions of the Jetpack components.

Our official AARs and JARs binaries are distributed through Google Maven.

You can learn more about using it from Android Jetpack landing page.

Contribution Guide

For contributions via GitHub, see the GitHub Contribution Guide.

Note: The contributions workflow via GitHub is currently experimental - only contributions to the following projects are being accepted at this time:

Code Review Etiquette

When contributing to Jetpack, follow the code review etiquette.

Accepted Types of Contributions

  • Bug fixes - needs a corresponding bug report in the Android Issue Tracker
  • Each bug fix is expected to come with tests
  • Fixing spelling errors
  • Updating documentation
  • Adding new tests to the area that is not currently covered by tests
  • New features to existing libraries if the feature request bug has been approved by an AndroidX team member.

We are not currently accepting new modules.

Checking Out the Code

NOTE: You will need to use Linux or Mac OS. Building under Windows is not currently supported.

  1. Install repo (Repo is a tool that makes it easier to work with Git in the context of Android. For more information about Repo, see the Repo Command Reference)
mkdir ~/bin
PATH=~/bin:$PATH
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a+x ~/bin/repo
  1. Configure Git with your real name and email address.
git config --global user.name "Your Name"
git config --global user.email "you@example.com"
  1. Create a directory for your checkout (it can be any name)
mkdir androidx-main
cd androidx-main
  1. Use repo command to initialize the repository.
repo init -u https://android.googlesource.com/platform/manifest -b androidx-main --partial-clone --clone-filter=blob:limit=10M
  1. Now your repository is set to pull only what you need for building and running AndroidX libraries. Download the code (and grab a coffee while we pull down the files):
repo sync -j8 -c

You will use this command to sync your checkout in the future - it’s similar to git fetch

Using Android Studio

To open the project with the specific version of Android Studio recommended for developing:

cd path/to/checkout/frameworks/support/
ANDROIDX_PROJECTS=MAIN ./gradlew studio

and accept the license agreement when prompted. Now you're ready to edit, run, and test!

You can also the following sets of projects: ALL, MAIN, COMPOSE, or FLAN

If you get “Unregistered VCS root detected” click “Add root” to enable git integration for Android Studio.

If you see any warnings (red underlines) run Build > Clean Project.

Builds

Full Build (Optional)

You can do most of your work from Android Studio, however you can also build the full AndroidX library from command line:

cd path/to/checkout/frameworks/support/
./gradlew createArchive

Testing modified AndroidX Libraries to in your App

You can build maven artifacts locally, and test them directly in your app:

./gradlew createArchive

And put the following at the top of your ‘repositories’ property in your project build.gradle file:

maven { url '/path/to/checkout/out/androidx/build/support_repo/' }

NOTE: In order to see your changes in the project, you might need to clean your build (Build > Clean Project in Android Studio or run ./gradlew clean).

Continuous integration

Our continuous integration system builds all in progress (and potentially unstable) libraries as new changes are merged. You can manually download these AARs and JARs for your experimentation.

Running Tests

Single Test Class or Method

  1. Open the desired test file in Android Studio.
  2. Right-click on a test class or @Test method name and select Run FooBarTest

Full Test Package

  1. In the project side panel open the desired module.
  2. Find the directory with the tests
  3. Right-click on the directory and select Run androidx.foobar

Running Sample Apps

The AndroidX repository has a set of Android applications that exercise AndroidX code. These applications can be useful when you want to debug a real running application, or reproduce a problem interactively, before writing test code.

These applications are named either <libraryname>-integration-tests-testapp, or support-\*-demos (e.g. support-v4-demos or support-leanback-demos). You can run them by clicking Run > Run ... and choosing the desired application.

Password and Contributor Agreement before making a change

Before uploading your first contribution, you will need setup a password and agree to the contribution agreement:

Generate a HTTPS password: https://android-review.googlesource.com/new-password

Agree to the Google Contributor Licenses Agreement: https://android-review.googlesource.com/settings/new-agreement

Making a change

cd path/to/checkout/frameworks/support/
repo start my_branch_name .
# make needed modifications...
git commit -a
repo upload --current-branch .

If you see the following prompt, choose always:

Run hook scripts from https://android.googlesource.com/platform/manifest (yes/always/NO)?

If the upload succeeds, you'll see output like:

remote:
remote: New Changes:
remote:   https://android-review.googlesource.com/c/platform/frameworks/support/+/720062 Further README updates
remote:

To edit your change, use git commit --amend, and re-upload.

Getting reviewed

  • After you run repo upload, open r.android.com
  • Sign in into your account (or create one if you do not have one yet)
  • Add an appropriate reviewer (use git log to find who did most modifications on the file you are fixing or check the OWNERS file in the project's directory)

Handling binary dependencies

AndroidX uses git to store all the binary Gradle dependencies. They are stored in prebuilts/androidx/internal and prebuilts/androidx/external directories in your checkout. All the dependencies in these directories are also available from google(), jcenter(), or mavenCentral(). We store copies of these dependencies to have hermetic builds. You can pull in a new dependency using our importMaven tool.