Files

T

SoftwareApp 667a85f80c Remember what is in the trash, and add a screen to restore from it

The staged-delete work left a hole. The undo handle lived in BrowserUiState, so a delete from an earlier session was unreachable even though the files were sitting on the volume; and because nothing on disk recorded which folder an item came from, not even the user could put one back by hand with confidence. Adding a Trash screen alone would not have fixed it: the recovery data did not survive the process. So the origin is now written at delete time.

data/ gains its first persistence: a SQLite index (staged path, original path, name, type, size, timestamp). SQLite rather than Room because an annotation processor is a large addition to this build for one table and three queries, and behind a TrashIndex port so domain/Trash keeps no Context while the tests drive it with a map and the real one is still tested against real SQLite. New Trash entry in the overflow menu lists batches and restores a whole one.

The index is an index, not the truth: the staged files are the truth, and the two can disagree if a user empties the folder by hand or pulls a card. Reconciled both ways - restorableFrom drops entries whose file has gone, purgeExpired forgets entries whose folder has gone and sweeps folders no entry mentions - and rows are written after the move, so a crash leaves an unindexed folder (harmless, swept) rather than an entry that could never restore. Verified on hardware: delete, force-stop, relaunch, restore.

Also corrects the docs where they claimed input swipe x y x y 900 is delivered as a plain tap on MIUI. It does open the selection bar - it was driven that way - but it has also landed as a tap, so it is flaky rather than impossible.

2026-10-15 10:25:37 +02:00

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File Manager

An ad-free, one-time-paid Android file manager. It browses and manages the files on your device — locally, with no ads, no account and no analytics.

Nothing ever leaves the device: the app declares no network permission and contains no advertising or tracking SDKs.

Working title. The display name and the store listing are decided before the first Play upload (see docs/ROADMAP.md, M10). The applicationId is already fixed and can never change after the first release.

Status

M10 — store assets: done. The app is named Plain Files, the icon and feature graphic are generated from the app's own vectors, and docs/STORE_LISTING.md holds length-checked listing copy. The screenshots are captured: 5 phone (1080×2160), 4 on a 7-inch tablet (1200×1920) and 4 on a 10-inch tablet (2560×1600).

Tech stack

Area	Choice
Language	Kotlin 2.4.10 (using AGP 9 built-in Kotlin)
UI	Jetpack Compose, BOM 2026.06.01, Material 3
Build	Gradle 9.3.1, Android Gradle Plugin 9.1.0
Storage access	`MANAGE_EXTERNAL_STORAGE` ("All files access") with a Storage Access Framework fallback
Archives	Apache Commons Compress + XZ for Java (both pure Java — no NDK)
SDK levels	`compileSdk`/`targetSdk` 36, `minSdk` 26

targetSdk is 36 because Google Play requires new apps and updates to target Android 16 (API 36) from 31 August 2026.

Project layout

app/src/main/java/de/softwareapp_hb/filemanager/
├── core/      Pure-Kotlin engine (no Android imports!) — paths, sorting, formatting,
│              search matching, copy/move planning, conflict policy
├── data/      Storage backends (all-files access + SAF), volumes, shares coming in
│              from other apps, the trash index (SQLite), file operations, archives,
│              deletion
├── domain/    Browser + operation controllers, models, permission state
├── service/   Foreground service for long-running file operations
├── ui/        Compose theme, browser screen, components, ViewModels
└── text/      Domain enum → string-resource mapping
app/src/test/java/…            JVM unit tests for the core engine

core/ deliberately has no Android dependencies, so the trickiest logic is covered by fast JVM tests.

Building

Prerequisites:

JDK 17+ (JDK 25 verified)
Android SDK with platforms;android-36 and build-tools;36.0.0

# Tell Gradle where the SDK lives (this file is git-ignored)
echo "sdk.dir=$HOME/Android/Sdk" > local.properties

./gradlew :app:assembleDebug        # debug APK
./gradlew :app:testDebugUnitTest    # JVM unit tests for the engine
./gradlew :app:lintDebug            # Android Lint
./gradlew :app:bundleRelease        # Play upload bundle (.aab)

Release signing is optional and driven by a git-ignored keystore.properties (see keystore.properties.example); without it the release build still runs R8/minification but produces an unsigned artefact.

Tracked in git

Source, resources and Gradle build files.
docs/ — roadmap and release documentation.
PRIVACY.md, CHANGELOG.md, and (from M10) store-assets/.

Not tracked: local.properties, keystore.properties, *.jks, build outputs.

Releasing

Release signing is driven by the git-ignored keystore.properties (see keystore.properties.example). Without that file the release build still runs R8 and resource shrinking, but produces an unsigned artefact that cannot be uploaded.

./gradlew :app:bundleRelease                      # Play upload bundle (.aab)
./gradlew :app:assembleRelease                    # APK, for local checks

# Audit what is actually shipped — in particular that there is no INTERNET permission:
$ANDROID_HOME/build-tools/36.0.0/aapt2 dump permissions \
  app/build/outputs/apk/release/app-release.apk

Read docs/PLAY_RELEASE_CHECKLIST.md before uploading. Step 4 is the one that matters most for this app: a file manager must declare "All files access" through Play's Permissions Declaration Form, and have the core purpose documented in its store description. PRIVACY.md is written to match the shipped permissions.

Localisation

All user-visible text lives in app/src/main/res/values/strings.xml, with real <plurals> wherever a count can be one, and the screen and the progress notification resolve their labels through text/TextRes.kt so the two cannot drift apart. English is currently the only locale.

Adding a language is then a file, not a refactor:

app/src/main/res/values-de/strings.xml   # same keys, translated values

Deliberately not localised, and why:

Byte units ("KB", "MB") — symbols, not words, and every file manager and the system Settings app show them the same way.
The timestamp pattern (yyyy-MM-dd HH:mm) — a fixed, sortable format; the zone is passed in explicitly rather than assumed.

Checking that nothing was missed

Two things are easy to get wrong: a literal typed into a composable, and showing an enum constant directly (FileKind.name puts untranslatable English on screen — the details sheet used to do exactly that). The mechanical check is the pseudo-locale:

./gradlew :app:assembleDebug
# Settings > System > Languages > English (XA), then launch the debug build.

The debug build type sets isPseudoLocalesEnabled = true, so every string that came from strings.xml renders accented and bracketed ([Îmàgé]). Anything that looks normal is a string that never went through resources. The release build is unaffected.

One caveat: Google Play's automatic translation translates your store listing, not the app UI. Translated UI text has to be supplied in values-<locale>/.

Known limitations

The trash is a time window, not a bin you manage. A delete stages the item in a hidden .plainfiles-trash folder on the same volume and keeps it for 24 hours; the Trash entry in the overflow menu lists what is still there and puts a whole batch back. There is no "empty it now" action — expired batches are swept the next time something is deleted — and a name taken again in the meantime is never overwritten, so a restored item can arrive beside the new one rather than replacing it.
Where a trashed item came from is remembered in the app's own database, not on the volume. The staged files are the truth and the database is only an index, so the two are reconciled in both directions: an entry whose file has gone is not offered back, and a batch folder no entry mentions is swept.
Sharing a file out only works in the all-files mode. A SAF path is relative to the granted tree rather than a filesystem path, so it cannot be handed to FileProvider. Receiving a share and being picked from another app's chooser work either way: the first needs no filesystem path, and the second falls back to RESULT_CANCELED rather than returning a URI the caller could not read.
RAR, CAB, ISO and WIM are refused, not supported — they need native code, which this project deliberately does not ship. (The Commons Compress jar contains no RAR classes at all.) 7z is different: Commons Compress reads it in pure Java, so it is supported — but the format needs a seekable channel rather than a stream, because its header lives at the end of the file. All-files access can supply one; the SAF fallback cannot, so 7z extraction reports that plainly in folder mode instead of half-working.
7z files can be opened but not created — writing stays ZIP-only.
Archive extraction does not restore original timestamps or permissions, and there is no archive encryption or password support.
Cancellation happens between entries, so a single very large file finishes before a stop is honoured.
View state is not persisted across process death (SavedStateHandle is not wired up).
Long-press multi-select is awkward to script from the host. The gesture that opens the selection bar (input swipe x y x y 900) works on the MIUI test device but has also registered as a plain tap, so compress/extract from the UI wants a manual pass (see docs/EDGE_CASE_TESTING.md).
The display name is still the working title — decided before the first upload (M10).

Monetisation

One-time paid: €4.49 base, with a €2.29 launch price for the first 14 days. No ads, no subscription, no in-app purchases, no free tier.

The price lives on the Play listing, not in the build, which is why there is no Billing client in the dependencies and no com.android.vending.BILLING permission in the APK — that is what keeps "no network permission, nothing leaves your device" true of the shipped artefact rather than just the source. Rationale, market anchors, the rejected alternatives and the Console steps: docs/MONETISATION.md.

⚠️ The price must be set before the first upload — Play allows paid → free but never free → paid.

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