feat: updates `@DevicePreviews` to use the Devices object constants by telpirion · Pull Request #2038 · android/nowinandroid

telpirion · 2026-01-15T21:38:47Z

What I have done and why

The NiaApp.kt file lacked @Preview annotations; I added a preview.
The ForYouScreen.kt file lacked a preview for onboarding & not populated; I added a preview.
The @DevicePreviews annotation didn't show different form factors; they were always portrait. I changed the annotation so that it uses the constants from the Devices object.

gemini-code-assist · 2026-01-15T21:39:06Z

Summary of Changes

Hello @telpirion, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the preview capabilities within the application by updating the @DevicePreviews annotation to leverage standard device constants, ensuring a more accurate representation of UI across different form factors. It also introduces new previews for key screens and refactors build configurations, streamlining the development and testing process for Compose UI components.

Highlights

Enhanced Device Previews: The @DevicePreviews annotation has been updated to utilize constants from the androidx.compose.ui.tooling.preview.Devices object, ensuring that previews now correctly display various form factors beyond just portrait mode.
New Previews Added: Previews have been added for NiaApp.kt and ForYouScreen.kt (specifically for the onboarding and not-populated states) to improve visual testing and development workflow.
Build Configuration Update: The core/datastore-proto/build.gradle.kts file has been cleaned up by removing redundant source set registration for protobuf generated files, and a new androidx-navigationevent-compose dependency has been added to app/build.gradle.kts.
Conditional Rendering for Previews: The ForYouEntryProvider.kt now includes conditional rendering logic using LocalInspectionMode.current to provide mock data for ForYouScreen when in preview mode, simplifying preview setup.

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Code Review

This pull request significantly improves the Jetpack Compose previews by updating @DevicePreviews to use standard Devices constants and adding new previews for NiaApp and ForYouScreen. The changes make the previews more robust and easier to maintain. I've also included a suggestion to refactor the preview setup in ForYouEntryProvider.kt to improve code clarity and reduce verbosity.

...n/com/google/samples/apps/nowinandroid/feature/foryou/impl/navigation/ForYouEntryProvider.kt

telpirion

Bad Code Assist, no donut

dturner

Thanks for the PR. Made a few suggestions and have a few questions.

dturner · 2026-01-26T19:22:12Z

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/NiaApp.kt

                    ),
                )
            },
+            // Fix for render issue: Scaffold crashes with "List is empty" when contentWindowInsets is set


Please add a link to the issue so we can remove this workaround when it's fixed.

dturner · 2026-01-26T19:24:10Z

app/src/testDemo/screenshots/compactWidth_compactHeight_showsNavigationBar.png

The news cards are an important part of the screenshots because they improve test fidelity - is there a reason why they've been removed from all the screenshots?

That change wasn't intentional, I assure you. Perhaps one of the GitHub bots made this change? I'll look into it.

No worries. There is a step in the build workflow that generates new screenshots based on the changes in your PR. This is so that you, the PR owner, can visually verify that the changes you've made have the desired effect, or allows you to spot when you've changed something that inadvertently changes the UI.

In this case, it sounds like the latter so you need to fix the news resources being displayed. The current screenshots will be removed from the PR after you push the code changes and the build workflow completes.

dturner · 2026-01-26T19:28:18Z

core/datastore-proto/build.gradle.kts

    }
 }

-androidComponents.beforeVariants {


Why has this been removed? Usually if it's not directly related to the PR it should go in a separate PR.

This change was made by Gemini. I believe it was done to address a build error. I'll see if I can revert this without breaking the PR.

This change has already been made on main in #2051. You can revert the changes made to this file and rebase.

dturner · 2026-01-26T19:32:58Z

...n/com/google/samples/apps/nowinandroid/feature/foryou/impl/navigation/ForYouEntryProvider.kt

-        ForYouScreen(
-            onTopicClick = navigator::navigateToTopic,
-        )
+        if (LocalInspectionMode.current) {


This pollutes the production code with code that is only used for previews. Are there any alternatives to doing this? Maybe have a different entryProvider that is used for previews instead?

dturner · 2026-01-26T19:38:23Z

gradle/libs.versions.toml

 androidx-navigation-testing = { group = "androidx.navigation", name = "navigation-testing", version.ref = "androidxNavigation" }
 androidx-navigation3-runtime = { group = "androidx.navigation3", name = "navigation3-runtime", version.ref = "androidxNavigation3" }
 androidx-navigation3-ui = { group = "androidx.navigation3", name = "navigation3-ui", version.ref = "androidxNavigation3" }
+androidx-navigationevent-compose = { group = "androidx.navigationevent", name = "navigationevent-compose", version = "1.0.1" }


Please follow the convention for all other dependencies by moving the version number into a variable at the top of the file.

dturner · 2026-01-26T19:45:29Z

...mpl/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/foryou/impl/ForYouScreen.kt

+        ForYouScreen(
+            isSyncing = true,
+            onboardingUiState = OnboardingUiState.Shown(
+                topics = emptyList(),


If there is a justification for adding this preview, using topics = emptyList() here means this is not a realistic preview of the ForYouScreen when the onboarding UI is shown. There's code from the other previews that can be copied here to load the topics.

As mentioned previously, it's realistic in the sense that it's a state I encountered. Specifically when running on a tablet.

You encountered a state where the onboarding was shown but there were no topics in it? If so, that's a bug, and we shouldn't provide previews for buggy states.

The correct state to preview should be that the onboarding has topics in it.

...mpl/src/main/kotlin/com/google/samples/apps/nowinandroid/feature/foryou/impl/ForYouScreen.kt

feat: updates @DevicePreviews to use the Devices object constants

dfc6a17

telpirion requested a review from dturner as a code owner January 15, 2026 21:38

gemini-code-assist bot reviewed Jan 15, 2026

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...n/com/google/samples/apps/nowinandroid/feature/foryou/impl/navigation/ForYouEntryProvider.kt Show resolved Hide resolved

telpirion commented Jan 15, 2026

View reviewed changes

telpirion and others added 3 commits January 15, 2026 13:51

fix linter issues

2ef8430

🤖 Updates baselines for Dependency Guard

1e43a41

🤖 Updates screenshots

e490faa

dturner requested changes Jan 26, 2026

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telpirion commented Jan 15, 2026

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gemini-code-assist bot commented Jan 15, 2026

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dturner Jan 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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dturner Jan 26, 2026 •

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