fix(thumbail): generation

[alperozturk96]

Issue

Thumbnail for video files were not visible on Upload and Media tab. Code was duplicated for every class and was error prone.

Changes

• Unifies thumbnail generation logic for files and folder in one class
• Unifies cache key usages
• Deduplicates cache key and Bitmap
• Checks remote file preview availability before attempting to download preview
• Saves remote file preview availability after upload
• Replaces deprecated API usages
• Fixes and unifies thumbnail generation for media, upload, file listing screens
• Eliminates DisplayUtils.setThumbnail calls with a lot of parameters. For example:

Note

Reasons to unify thumbnail logic:

DisplayUtils.setThumbnail was already covering all cases for folders and files, but it required many parameters. For each missing class, we had to inject and pass those parameters through multiple classes just to call the setThumbnail function. With this approach, only one injection is needed to access that logic, for example, in the Upload screen.

Reasons to unify keys:

Currently, keys are generated with long static class calls from ThumbnailCacheManager, and later the bitmap is checked and retrieved again from the same ThumbnailCacheManager. This repeated pattern exists across many classes. Instead, we can unify this logic and simply call methods like getSmallBitmap or getBigBitmap.

Additionally, a single incorrect usage of a key prefix can cause the cached bitmap to be missed. For example, using remotePath or hashCode instead of remoteId for an OCFile cached bitmap will result in a cache miss. Therefore, we should avoid hardcoding these values and copying them across the application.

For local file hashCode needs to be used this change also will prevent this.

Screenshot

Before Upload Screen	After Upload Screen

[Copilot]

Pull request overview

This PR centralizes thumbnail generation across the legacy com.owncloud.android.* UI surfaces by introducing a DI-managed ThumbnailGenerator (file + folder) and migrating callers away from the large DisplayUtils.setThumbnail(...) logic and ad-hoc cache-key handling. It also standardizes cache key access via OCFile/extension helpers and persists server preview availability after upload.

Changes:

• Introduces ThumbnailGenerator / FileThumbnailGenerator / FolderThumbnailGenerator and migrates multiple adapters/fragments/activities to use it.
• Unifies thumbnail cache key usage (small/big) via OCFile helpers and FileExtensions functions; updates call sites and tests accordingly.
• Adds preview-availability checks to avoid pointless remote preview downloads and persists previewAvailable on upload.

Reviewed changes

Copilot reviewed 38 out of 38 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
app/src/test/java/com/owncloud/android/ui/adapter/GalleryAdapterTest.kt	Updates unit test construction to pass the new ThumbnailGenerator dependency.
app/src/main/java/com/owncloud/android/utils/DisplayUtils.java	Removes the large thumbnail-setting implementation now replaced by the new generator classes.
app/src/main/java/com/owncloud/android/ui/preview/PreviewImageFragment.kt	Switches preview thumbnail and resized-image cache key usage to OCFile helpers.
app/src/main/java/com/owncloud/android/ui/fragment/UnifiedSearchFragment.kt	Injects ThumbnailGenerator and passes it into the unified search adapter.
app/src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java	Injects ThumbnailGenerator and wires it into file list adapter construction.
app/src/main/java/com/owncloud/android/ui/fragment/GalleryFragment.kt	Passes ThumbnailGenerator into GalleryAdapter.
app/src/main/java/com/owncloud/android/ui/fragment/FileDetailFragment.java	Uses OCFile thumbnail helpers for preview/thumbnail display.
app/src/main/java/com/owncloud/android/ui/dialog/ConflictsResolveDialog.kt	Uses ThumbnailGenerator instead of DisplayUtils.setThumbnail(...).
app/src/main/java/com/owncloud/android/ui/adapter/uploadList/UploadListAdapter.kt	Replaces custom thumbnail generation with ThumbnailGenerator, adds async OCFile lookup.
app/src/main/java/com/owncloud/android/ui/adapter/UnifiedSearchListAdapter.kt	Replaces OverlayManager with ThumbnailGenerator in adapter dependencies.
app/src/main/java/com/owncloud/android/ui/adapter/UnifiedSearchItemViewHolder.kt	Uses ThumbnailGenerator for folder overlays and file thumbnails.
app/src/main/java/com/owncloud/android/ui/adapter/UnifiedSearchCurrentDirItemViewHolder.kt	Uses ThumbnailGenerator for current-directory item thumbnails.
app/src/main/java/com/owncloud/android/ui/adapter/TrashbinListAdapter.java	Switches trashbin thumbnail lookups to getSmallThumbnail() helper.
app/src/main/java/com/owncloud/android/ui/adapter/OCFileListDelegate.kt	Removes DisplayUtils thumbnail path and delegates thumbnailing to ThumbnailGenerator.
app/src/main/java/com/owncloud/android/ui/adapter/OCFileListAdapter.java	Plumbs ThumbnailGenerator through and routes cancellation to generator task cancellation.
app/src/main/java/com/owncloud/android/ui/adapter/LocalFileListAdapter.java	Uses FileExtensionsKt.getSmallThumbnail(...) for local thumbnail reads.
app/src/main/java/com/owncloud/android/ui/adapter/GalleryAdapter.kt	Uses ThumbnailGenerator for task cancellation and list thumbnail generation flow.
app/src/main/java/com/owncloud/android/ui/activity/UploadListActivity.kt	Injects and passes ThumbnailGenerator into UploadListAdapter.
app/src/main/java/com/owncloud/android/ui/activity/ShareActivity.kt	Uses ThumbnailGenerator for file icon/thumbnail display.
app/src/main/java/com/owncloud/android/ui/activity/EditorWebView.java	Uses OCFile.getSmallThumbnail() for cached thumbnail reads.
app/src/main/java/com/owncloud/android/providers/DocumentsStorageProvider.java	Uses getSmallThumbnailKey() for thumbnail existence checks.
app/src/main/java/com/owncloud/android/providers/DiskLruImageCacheFileProvider.java	Uses small/big thumbnail helpers for disk-cache lookup.
app/src/main/java/com/owncloud/android/operations/UploadFileOperation.java	Persists previewAvailable from server metadata on upload completion.
app/src/main/java/com/owncloud/android/datamodel/ThumbnailsCacheManager.java	Switches to unified key helpers; skips remote download when server has no preview.
app/src/main/java/com/owncloud/android/datamodel/OCFile.java	Adds Java-level convenience methods for thumbnail keys and bitmap retrieval.
app/src/main/java/com/nextcloud/utils/thumbnail/ThumbnailGenerator.kt	New: single entry point choosing file vs folder vs offline thumbnail generation.
app/src/main/java/com/nextcloud/utils/thumbnail/FolderThumbnailGenerator.kt	Moves/renames overlay manager responsibilities into folder thumbnail generation.
app/src/main/java/com/nextcloud/utils/thumbnail/FileThumbnailGenerator.kt	New: centralized file thumbnail generation, task management, shimmer handling.
app/src/main/java/com/nextcloud/utils/ShortcutUtil.kt	Uses OCFile.smallThumbnail helper for shortcut icon generation.
app/src/main/java/com/nextcloud/utils/extensions/ImageViewExtensions.kt	Adds startShimmer/stopShimmer extensions used by new thumbnail code.
app/src/main/java/com/nextcloud/utils/extensions/FileExtensions.kt	Adds thumbnail key/bitmap helpers for ServerFileInterface and File.
app/src/main/java/com/nextcloud/ui/trashbinFileActions/TrashbinFileActionsBottomSheet.kt	Uses ThumbnailGenerator for bottom-sheet thumbnail display.
app/src/main/java/com/nextcloud/ui/fileInfo/ImageDetailInfo.kt	Uses OCFile.smallThumbnail for pin/avatar-style thumbnail composition.
app/src/main/java/com/nextcloud/ui/fileactions/FileActionsBottomSheet.kt	Uses ThumbnailGenerator for bottom-sheet thumbnail display.
app/src/main/java/com/nextcloud/client/jobs/gallery/GalleryImageGenerationJob.kt	Switches resized-image caching to bigThumbnailKey/getBigThumbnail().
app/src/main/java/com/nextcloud/client/di/AppModule.java	Provides FolderThumbnailGenerator instead of the old OverlayManager.
app/src/androidTest/java/com/owncloud/android/ui/fragment/GalleryFragmentIT.kt	Updates instrumented test to use bigThumbnailKey and bigThumbnail helper.
app/src/androidTest/java/com/owncloud/android/ui/adapter/UnifiedSearchListAdapterIT.kt	Updates IT to construct and pass ThumbnailGenerator instead of OverlayManager.

Suppressed comments (2)

app/src/main/java/com/owncloud/android/datamodel/ThumbnailsCacheManager.java:732

• In doFileInBackground(), the disk-cache key is now prefixed via FileExtensionsKt.getSmallThumbnailKey(file), but the code still reads/writes using the unprefixed imageKey (hashCode string). This breaks local thumbnail cache lookups via the new FileExtensionsKt.getSmallThumbnail() API (it looks up the prefixed key).

            final String imageKey = Objects.requireNonNullElseGet(mImageKey, () -> String.valueOf(file.hashCode()));

            // local file should always generate a thumbnail
            mImageKey = FileExtensionsKt.getSmallThumbnailKey(file);

            // Check disk cache in background thread
            Bitmap thumbnail = getBitmapFromDiskCache(imageKey);

app/src/main/java/com/nextcloud/utils/thumbnail/FolderThumbnailGenerator.kt:6

• SPDX header doesn’t match the repository’s documented template (see AGENTS.md:43-61). New files should use “Nextcloud GmbH and Nextcloud contributors” instead of a personal attribution line.

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[github-actions]

APK file: https://github.com/nextcloud/android/actions/runs/31163294377/artifacts/8988442890
To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.
(please click on link to get QR code displayed)

[github-actions]

Codacy

SpotBugs

Category	Base	New
Bad practice	32	32
Correctness	64	64
Dodgy code	215	213
Experimental	1	1
Malicious code vulnerability	2	2
Multithreaded correctness	25	25
Performance	40	40
Security	19	19
Total	398	396

[github-actions]

APK file: https://github.com/nextcloud/android/actions/runs/31164847648/artifacts/8988692318
To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.
(please click on link to get QR code displayed)

[github-actions]

blue-Light-Screenshot test failed, but no output was generated. Maybe a preliminary stage failed.

[github-actions]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17448-IT-master-10-06