Make it easy to register for activity results from a Composable [172690553]

Fixed

Feature Request

Status Update

No update yet.

Description

il...@google.com

created issue #1

Nov 6, 2020 11:36PM

Jetpack Compose release version: 1.0.0-alpha06

The Activity Result API and specifically the ActivityResultRegistry APIs are currently much easier to work with from activities and fragments as they implement ActivityResultCaller and provide an easy to use registerForActivityResult() API.

Something similar should be directly available for Composables. I don't think it is important to specifically implement ActivityResultCaller, but perhaps just providing a Compose specific version of registerForActivityResult():

@Composable
fun <I, O> registerForActivityResult(
    contract: ActivityResultContract<I, O>,
    onResult: (O) -> Unit
) : ActivityResultLauncher<I>

As demonstrated in this StackOverflow answer. This would handle the appropriate register and unregister calls given the lifetime of the composable.

Comments

lo...@gmail.com <lo...@gmail.com> #2Jan 31, 2021 06:42AM

Besides usage in Compose, it'd be great for that API to be less coupled to Activity and Fragment for the cases you want your code to be modular and it relies on activity results.

il...@google.com <il...@google.com> #3Jan 31, 2021 06:57AM

Re #2 - it isn't tied to Activity or Fragment as per the guide for receiving an activity result in a separate class.

ez...@gmail.com <ez...@gmail.com> #4Jan 31, 2021 07:36AM

It is tied to the Activity or Fragment's lifecycle, but a Composable's lifecycle is dependand of the Activity or Fragment.

And simply providing the Registery for the Composable will cause an exception because you can only register a new caller before onStart

lo...@gmail.com <lo...@gmail.com> #5Jan 31, 2021 08:53AM

Exactly, the API façade doesn't show it being tied to an Activity or a Fragment, but the actual implementation is definitely coupled to it because of this requirement, which I guess should be replaced with an alternative mechanism that can be registered later on (though the fastest is the best, for the cases where the process was killed).

il...@google.com <il...@google.com> #6Feb 1, 2021 01:10AM

Re #4, #5 - tying it to a Lifecycle is totally optional convenience and has always been totally optional (that's why there's a second version of register that doesn't take a Lifecycle).

You'll see from the StackOverflow answer listed in comment#1 that it works fine from a composable, using its DisposableEffect and unregistering in onDispose, no Lifecycle required.

ap...@google.com <ap...@google.com> #7Feb 4, 2021 07:36PM

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

commit 1675fd6d1a791b8b236a2a89af1c85ade809abb8
Author: Jeremy Woods <jbwoods@google.com>
Date: Wed Feb 03 14:21:24 2021

Improve integration between ActivityForResult and Compose

Adding a CompositionLocal for getting an ActivityResultRegistryOwner
from a composable and a registerForActivityResult helper method to make
it easier to get ActivityResults from Composables.

RelNote: "There is a now a Composable registerForActivityResult function
for getting results from activities within composables."
Test: ActivityResultRegistryTest
Bug: 172690553

Change-Id: Ia78515f6693ebf6f1997ee0109df87dcc388dda7

M activity/activity-compose/api/current.txt
M activity/activity-compose/api/public_plus_experimental_current.txt
M activity/activity-compose/api/restricted_current.txt
M activity/activity-compose/build.gradle
A activity/activity-compose/samples/src/main/java/androidx/activity/compose/samples/RegisterForActivityResultSample.kt
A activity/activity-compose/src/androidTest/java/androidx/activity/compose/ActivityResultRegistryTest.kt
A activity/activity-compose/src/main/java/androidx/activity/compose/ActivityComposeUtils.kt
A activity/activity-compose/src/main/java/androidx/activity/compose/ActivityResultRegistry.kt
M activity/activity-compose/src/main/java/androidx/activity/compose/BackHandler.kt

https://android-review.googlesource.com/1569321

il...@google.com <il...@google.com> #8Feb 11, 2021 12:14AM

Marked as fixed.

This didn't land in Activity Compose 1.3.0-alpha02, but it will be available in an upcoming Activity Compose 1.3.0-alpha03 release.

no...@gmail.com <no...@gmail.com> #9Mar 18, 2021 10:11AM

After migrating from the old activity.registerForActivityResult to this mechanism, I received this error from down the call stack:

java.lang.IllegalArgumentException: Can only use lower 16 bits for requestCode

If someone else has this problem, it can be fixed by adding the following dependency, as suggested in this SO answer:

implementation 'androidx.fragment:fragment:1.3.0'

il...@google.com <il...@google.com> #10Mar 18, 2021 03:57PM

Re #9 - this is also specifically called out in the Activity release notes:

Note: when upgrading to Activity 1.2.0, you must upgrade to Fragment 1.3.0 to fix issues with invalid request codes and ensure that permission requests are delivered correctly. The InvalidFragmentVersionForActivityResult Lint check will warn you if you do not upgrade to an appropriate Fragment version.