IssueTracker

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

commit c60f33e229e31ab328ef6b59dab63b264954831c
Author: Alexandre Elias <aelias@google.com>
Date:   Fri Jul 10 16:23:09 2020

    Semantics no-op cleanups
   
    Partly in response to lmr's broad code review, I did a pass of
    superficial API/implementation cleanup.  The main changes are:
   
    - I changed each Boolean SemanticsProperty where false is equivalent to
      not being present to take "Unit" instead.  This is conceptually
      clearer: it avoids questions like "can I cancel out a semantics from a
      merged child by setting it to false?"  Because "property = Unit" looks
      weird, I also changed the style of these to "property()".
   
    - I moved the Semantics id generator closer to where it's used, in
      SemanticsModifierCore.  I made it internal and an AtomicInt.
      (Note that integer ids are heavily used in the Android
      AccessibilityNodeInfo APIs so I can't simply remove them entirely.)
   
    - I deleted dead code.  Some examples include SemanticsHintOverrides,
      a public API not connected to anything, and SemanticsPropertyKey
      merge() open method which is never called.  (In both cases I have
      a different plan in mind for accessibility.)
   
    Fixes: 145951226
    Fixes: 145955412
    Test: existing tests
    Relnote: "Single-value semantics properties now use a calling style.
    For example, 'semantics { hidden = true }' is now written as:
    'semantics { hidden() }'."
   
    Change-Id: Ic1afd12ea22c926babc9662f1804d80b33aa0cfc

M       ui/integration-tests/benchmark/src/androidTest/java/androidx/ui/benchmark/test/LayoutNodeModifierBenchmark.kt
M       ui/ui-core/api/0.1.0-dev15.txt
M       ui/ui-core/api/current.txt
M       ui/ui-core/api/public_plus_experimental_0.1.0-dev15.txt
M       ui/ui-core/api/public_plus_experimental_current.txt
M       ui/ui-core/api/restricted_0.1.0-dev15.txt
M       ui/ui-core/api/restricted_current.txt
M       ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/graphics/vector/VectorTest.kt
M       ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/semantics/SemanticsTests.kt
M       ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidActuals.kt
M       ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeView.kt
M       ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeViewAccessibilityDelegateCompat.kt
M       ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidPopup.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/Expect.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsConfiguration.kt
D       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsHintOverrides.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsModifier.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsNode.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsOwner.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsWrapper.kt
M       ui/ui-core/src/commonMain/kotlin/androidx/ui/semantics/SemanticsProperties.kt
M       ui/ui-foundation/api/0.1.0-dev15.txt
M       ui/ui-foundation/api/current.txt
M       ui/ui-foundation/api/public_plus_experimental_0.1.0-dev15.txt
M       ui/ui-foundation/api/public_plus_experimental_current.txt
M       ui/ui-foundation/api/restricted_0.1.0-dev15.txt
M       ui/ui-foundation/api/restricted_current.txt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Selectable.kt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
M       ui/ui-foundation/src/main/java/androidx/ui/foundation/semantics/FoundationSemanticsProperties.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/ButtonTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/CardTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/CheckboxScreenshotTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/RadioButtonScreenshotTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/ScaffoldTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/SnackbarTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/SurfaceTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/ripple/RippleIndicationTest.kt
M       ui/ui-material/src/androidTest/java/androidx/ui/material/textfield/TextFieldScreenshotTest.kt
M       ui/ui-material/src/main/java/androidx/ui/material/AppBar.kt
M       ui/ui-material/src/main/java/androidx/ui/material/TextFieldImpl.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/AssertsTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/CallSemanticsActionTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/ErrorMessagesTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/FindersTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/PrintToStringTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/ScrollToTest.kt
M       ui/ui-test/src/androidTest/java/androidx/ui/test/TextActionsTest.kt
M       ui/ui-test/src/main/java/androidx/ui/test/Actions.kt
M       ui/ui-test/src/main/java/androidx/ui/test/Filters.kt
M       ui/ui-text/api/0.1.0-dev15.txt
M       ui/ui-text/api/current.txt
M       ui/ui-text/api/public_plus_experimental_0.1.0-dev15.txt
M       ui/ui-text/api/public_plus_experimental_current.txt
M       ui/ui-text/api/restricted_0.1.0-dev15.txt
M       ui/ui-text/api/restricted_current.txt
M       ui/ui-text/src/commonMain/kotlin/androidx/ui/text/CoreTextField.kt
M       ui/ui-text/src/commonMain/kotlin/androidx/ui/text/TextSemanticsProperties.kt

https://android-review.googlesource.com/1360099

Could you provide a minimal sample app for the issue you're facing? It'll help us investigate.

Thanks for pointing out the issue with my approach, will have to play around with it a bit more. I have attached a small sample project. It has two flavours: androidx and modified. The former is the unmodified adapter where as the later is with the changes I have made earlier (have not done any further experiments to fix the issue use case you were describing).

Modified the sample a bit to include some state saving. For a simple rotations, backgrounding and foregrounding the app I could not see anything in the first couple of runs. If you could also please give it a go and let me know what sequence of events reveal any issues I'd greatly appreciate it.

We've filed a bug on Navigation.

In the meantime, as a workaround, instead of creating a NavHostFragment directly as a page, create a regular Fragment subclass instance with a container inside it, and place NavHostFragment inside that container.
Container can be something simple, e.g. a FrameLayout with an id, e.g. generated by ViewCompat.generateId()

Note that the id on your FrameLayout should *not* use ViewCompat.generateId() as the ID needs to be stable across configuration changes. The issue filed against Navigation (https://issuetracker.google.com/issues/139421197) has been fixed for the upcoming Navigation 2.2.0-alpha02 - when using that version of Navigation, you wouldn't have to make any modifications to your ViewPager2 adapter and it would work with any version of ViewPager2.

Fixed in https://developer.android.com/jetpack/androidx/releases/navigation#2.2.0-alpha02