FragmentContainerView's getFragment() should respect nullability of its generic class [189629145]

Fixed

Feature Request

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Description

ia...@gmail.com

created issue #1

May 30, 2021 04:26AM

Component used: Fragment

Version used: 1.4.0-alpha01

The getFragment() method on FragmentContainerView is currently defined as:

fun <F : Fragment!> getFragment(): F?

Where the nullability of the returned fragment is not based on whether the generic passed to it is nullable or not.

It is expected that passing a non-null generic would result in a non-null fragment:

val mainFragment = binding.fragmentContainer.getFragment<MainFragment>()
// This currently fails since it thinks mainFragment is a MainFragment?
mainFragment.callMethod()

And similarly, passing in a nullable generic would result in a nullable fragment:

val optionalFragment = binding.fragmentContainer.getFragment<OptionalFragment?>()
// This should be correctly inferred as nullable
optionalFragment?.callMethod()

I suspect that this might require that this method be written in Kotlin to actually respect the nullability in generics.

Comments

il...@google.com <il...@google.com> Jun 10, 2021 05:34PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #2Sep 3, 2021 07:11PM

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

commit 57ca221882695bd6a52549f4d9ea3b812e6fe87c
Author: Simon Schiller <simonschiller@users.noreply.github.com>
Date: Mon Mar 22 16:09:30 2021

[GH] [FragmentStrictMode] Detect <fragment> tag usage

## Proposed Changes

- Detect `<fragment>` tag usage inside XML layouts

## Testing

Test: See `FragmentStrictModeTest#detectFragmentTagUsage`

## Issues Fixed

Fixes: 153738235

This is an imported pull request from

https://github.com/androidx/androidx/pull/141.

Resolves #141
Github-Pr-Head-Sha: 4ea052596e4341b9f11bcf335e2bc38045a91f19
GitOrigin-RevId: 62e7487aa4874eef6bb556490e193717cf937251
Change-Id: Iae48578e85e4e4897f806d7ade2e2a660adf9479

M fragment/fragment/api/public_plus_experimental_current.txt
M fragment/fragment/api/restricted_current.txt
M fragment/fragment/src/androidTest/java/androidx/fragment/app/strictmode/FragmentStrictModeTest.kt
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentLayoutInflaterFactory.java
M fragment/fragment/src/main/java/androidx/fragment/app/strictmode/FragmentStrictMode.java
A fragment/fragment/src/main/java/androidx/fragment/app/strictmode/FragmentTagUsageViolation.java

https://android-review.googlesource.com/1649748

jb...@google.com <jb...@google.com> #3Sep 3, 2021 07:12PM

Marked as fixed.

FragmentContainerView has been converted to Kotlin internally, and will be available in the Fragment 2.4.0-alpha09 release.

Issue 189629145

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il...@google.com <il...@google.com> Jun 10, 2021 05:34PM

ap...@google.com <ap...@google.com> #2Sep 3, 2021 07:11PM

jb...@google.com <jb...@google.com> #3Sep 3, 2021 07:12PM

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