Fix part of #5663: Use local thumbnails in dev builds by harshsomankar123-tech · Pull Request #6136 · oppia/oppia-android

harshsomankar123-tech · 2026-03-09T18:55:54Z

Explanation

Fix #5663 Part 01: Fixes activity thumbnail loading in developer builds by introducing a debug-only ContentProvider.

Context:
Currently, when thumbnailFilename is set in the proto files, it constructs a GCS URL and tries to fetch the image from the internet. Because developer builds don't have access to these GCS assets, the thumbnail loading fails. (The JSON loading path previously avoided this by falling back to local LessonThumbnailGraphic drawables, but that path is being removed).

Changes in this PR:

Introduces a developer/debug-only ContentProvider that intercepts thumbnail requests. For developer builds, it serves the local drawable assets instead of attempting to fetch GCS images.
Adds a debug-only Dagger module to configure this specific behavior for developer builds, ensuring the current GCS pipeline remains completely unchanged in production.

(Note: This PR strictly handles the thumbnail fix for dev builds. The JSON loading path removal is handled separately).

Essential Checklist

The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
Any changes to scripts/assets files have their rationale included in the PR explanation.
The PR follows the style guide.
The PR does not contain any unnecessary code changes from Android Studio (reference).
The PR is made from a branch that's not called "develop" and is up-to-date with "develop".
The PR is assigned to the appropriate reviewers (reference).

harshsomankar123-tech · 2026-03-09T18:56:20Z

@BenHenning @adhiamboperes PTAL

BenHenning · 2026-03-17T05:26:35Z

Apologies--hoping to look at this tomorrow.

BenHenning

@harshsomankar123-tech I left one comment on the PR and another on the issue. I don't think that this is being approached quite the correct way, PTAL.

Also, your PR description says that you've solved this with a custom ContentProvider but no ContentProvider has actually been proposed in code here.

BenHenning · 2026-03-17T21:05:06Z

app/src/main/java/org/oppia/android/app/customview/LessonThumbnailImageView.kt

      listOf()
    }
-    if (lessonThumbnail.thumbnailFilename.isNotEmpty()) {
+    if (lessonThumbnail.thumbnailFilename.isNotEmpty() && loadThumbnailsFromGcs) {


Have you tested this with proto lessons @harshsomankar123-tech? I wouldn't expect this to work, actually. I left more thoughts in #5663 (comment). PTAL.

…ev builds

harshsomankar123-tech · 2026-03-19T18:13:27Z

@BenHenning Thanks for the suggestions. I’ve made the changes mentioned in your comments.PTAL

oppiabot · 2026-03-19T18:16:32Z

Unassigning @harshsomankar123-tech since a re-review was requested. @harshsomankar123-tech, please make sure you have addressed all review comments. Thanks!

BenHenning

Thanks @harshsomankar123-tech! This is definitely on the right track. I have a bunch of comments, PTAL.

Also, after you address all of my comments could you add a video to the PR description showing loading with protos having correct thumbnails? Please make sure to correctly set up loading via CachingModule since protos aren't loaded by default in local dev builds currently.

BenHenning · 2026-03-19T22:19:52Z

app/src/main/java/org/oppia/android/app/application/dev/ThumbnailContentProvider.kt

+    sortOrder: String?
+  ): Cursor? = null
+
+  override fun getType(uri: Uri): String = "image/png"


Is this correct? Perhaps these could be SVGs, instead?

BenHenning · 2026-03-19T22:20:31Z

app/src/main/java/org/oppia/android/app/utility/imageloading/ThumbnailContentProvider.kt

+      "baker.img" to R.drawable.lesson_thumbnail_graphic_baker,
+      "child_with_book.img" to R.drawable.lesson_thumbnail_graphic_child_with_book,
+      "child_with_cupcakes.img" to R.drawable.lesson_thumbnail_graphic_child_with_cupcakes,
+      "child_with_fractions_homework.img" to
+        R.drawable.lesson_thumbnail_graphic_child_with_fractions_homework,
+      "duck_and_chicken.img" to R.drawable.lesson_thumbnail_graphic_duck_and_chicken,
+      "person_with_pie_chart.img" to R.drawable.lesson_thumbnail_graphic_person_with_pie_chart


Perhaps it would be cleaner to represent these as SVGs? We converted them to drawables originally because of how they were hooked up, but SVGs could be embedded as assets and returned directly (avoiding any temporarily file creation or loading needed).

BenHenning · 2026-03-19T22:22:38Z

app/src/main/java/org/oppia/android/app/application/dev/ThumbnailContentProvider.kt

@@ -0,0 +1,111 @@
+package org.oppia.android.app.application.dev


I think org.oppia.android.app.utility.imageloading is probably an okay place for now. This is a new pattern so we don't have an obvious place for it to go, but the current package is meant for top-level application setup which doesn't seem like the correct place.

The new package will need to be a proper Bazel package (i.e. with a BUILD.bazel) file, and you'll need to reference that new library target as a dependency for the top-level //:oppia_dev target as one of its dependencies.

BenHenning · 2026-03-19T22:23:42Z

domain/src/main/assets/GJ2rLXRKD5hw.textproto

 is_published: true
 has_practice_questions: true
 topic_thumbnail {
+  thumbnail_filename: "child_with_fractions_homework.img"


Here & elsewhere: how did you decide on which thumbnails to use? We ought to match exactly the current JSON behavior to make it an easier before-and-after check.

BenHenning · 2026-03-19T22:26:45Z

app/src/main/AndroidManifest.xml

+    <provider
+      android:name=".app.application.dev.ThumbnailContentProvider"
+      android:authorities="org.oppia.android.provider"
+      android:exported="false" />


This needs to go into its own AndroidManifest.xml in the same package as the content provider. We will rely on the manifest merge to include this at the end. Adding it here means we need to ship the provider in production which we absolutely don't want to do.

BenHenning · 2026-03-19T22:28:36Z

utility/src/main/java/org/oppia/android/util/parser/image/DevImageParsingModule.kt

+  @DefaultGcsPrefix
+  @Singleton
+  fun provideDefaultGcsPrefix(): String {
+    return "content://org.oppia.android.provider"


Let's use content://org.oppia.android.provider/gcs so as to not pollute future content provider potential.

BenHenning · 2026-03-19T22:29:28Z

utility/src/main/java/org/oppia/android/util/parser/image/BUILD.bazel

+kt_android_library(
+    name = "dev_image_parsing_module",
+    srcs = [
+        "DevImageParsingModule.kt",


The convention in the codebase is to use 'debug' for developer dependencies, and to put it at the end of the name before module, e.g. ImageParsingDebugModule. Please make sure to also update the library target name.

BenHenning · 2026-03-19T22:31:11Z

app/src/main/java/org/oppia/android/app/application/dev/ThumbnailContentProvider.kt

+      addURI(AUTHORITY, "*/*/*/*/#", THUMBNAIL_MATCH)
+      addURI(AUTHORITY, "*/*/*/*", THUMBNAIL_MATCH)
+      addURI(AUTHORITY, "thumbnail/*", THUMBNAIL_MATCH)
+      addURI(AUTHORITY, "#", THUMBNAIL_MATCH)


Are all of these needed? It seems like we will subpath based on <entity_type>/<entity_id>/assets/<image|thumbnail>/<file.name> which seems like it only needs a single URI matcher, or am I missing something?

…arsingDebugModule, update authority

oppiabot · 2026-03-28T00:14:16Z

Hi @harshsomankar123-tech, I'm going to mark this PR as stale because it hasn't had any updates for 7 days. If no further activity occurs within 7 days, it will be automatically closed so that others can take up the issue.
If you are still working on this PR, please make a follow-up commit within 3 days (and submit it for review, if applicable). Please also let us know if you are stuck so we can help you! If you're unsure how to reassign this PR to a reviewer, please make sure to review the wiki page that details the Guidance on submitting PRs.

adhiamboperes · 2026-04-08T08:07:30Z

@harshsomankar123-tech, please feel free to share any issues you are facing with this PR here or in Github Discussions.

harshsomankar123-tech · 2026-04-08T13:48:53Z

@adhiamboperes The CI is failing right now. I’ll work on fixing it and provide an update shortly.

Fix part of oppia#5663: Use local thumbnails in dev builds

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harshsomankar123-tech requested review from a team as code owners March 9, 2026 18:55

harshsomankar123-tech requested a review from adhiamboperes March 9, 2026 18:55

oppiabot bot assigned BenHenning Mar 9, 2026

BenHenning mentioned this pull request Mar 17, 2026

Fix part of #5663: Remove json lesson files #6143

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BenHenning assigned harshsomankar123-tech and unassigned BenHenning Mar 17, 2026

Fix part of oppia#5663: Use ContentProvider for local thumbnails in d…

e3d8a89

…ev builds

harshsomankar123-tech requested a review from a team as a code owner March 19, 2026 18:07

harshsomankar123-tech requested a review from BenHenning March 19, 2026 18:07

oppiabot bot assigned BenHenning and unassigned harshsomankar123-tech Mar 19, 2026

BenHenning requested changes Mar 19, 2026

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BenHenning assigned harshsomankar123-tech and unassigned BenHenning Mar 19, 2026

Address review comments: move ThumbnailContentProvider, rename ImageP…

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…arsingDebugModule, update authority

oppiabot bot added the stale Corresponds to items that haven't seen a recent update and may be automatically closed. label Mar 28, 2026

harshsomankar123-tech marked this pull request as draft March 28, 2026 00:44

oppiabot bot removed the stale Corresponds to items that haven't seen a recent update and may be automatically closed. label Mar 28, 2026

harshsomankar123-tech added 2 commits April 2, 2026 04:52

Fix CI: Remove duplicate Dagger module and add missing tests

b0a43e8

Fix CI: Resolve Bazel visibility and Kotlin lint errors

0cce034

Fix CI failures: Standardize KDoc and update textproto assets.

e9a0fc8

		@@ -0,0 +1,111 @@
		package org.oppia.android.app.application.dev

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harshsomankar123-tech commented Mar 9, 2026

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