Killion File Manager

A modern file manager for Android 13+, built entirely with Kotlin and Jetpack Compose.

Featuring a Material Design 3 interface, with privileged access, full-featured archiving, a private space, and file management capabilities.

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Project Overview

Killion File Manager (package com.killion.files) is a versatile file management tool whose goal is to combine "local file access + remote file access + privacy protection + file cleanup + root/shizuku support" into a single lightweight, smooth app:

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Supported Languages

The Killion interface is available in 25 languages (English is the default fallback):

• Arabic · Chinese (Simplified & Traditional) · Czech · Danish · Dutch
• English (default) · Finnish · French · German · Hebrew
• Hindi · Indonesian · Italian · Japanese · Korean
• Malay · Norwegian · Polish · Portuguese · Russian
• Spanish · Swedish · Thai · Turkish · Ukrainian · Vietnamese -Translated by AI; please correct any errors.

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Key Features

Privileged Access

• Dual channel: ROOT and Shizuku: Built on libsu and the Shizuku API, it can safely access restricted directories without unlocking the bootloader.
• Direct access to root: Browse the system root directory and protected paths via ROOT / Shizuku privilege escalation.
• Multiple storage volume switching: Long-press the "root directory" in the breadcrumb navigation bar to quickly select the current storage volume (internal / external SD / root).

Archive Management

• Multi-format extraction and creation: ZIP, 7Z, TAR.XZ, TAR.GZ.
• Encrypted compression: ZIP uses zip4j for AES-256 encryption; 7Z has built-in strong encryption.
• Split (volume) compression: Large files can be split into multiple volumes for easier transfer and storage.
• Smart thread scheduling: 7Z runs via a native 7zr subprocess and automatically injects -mmt (governing thread count by available cores); multiple tasks run in parallel via a unified scheduler (up to 3 concurrent tasks), balancing throughput and device smoothness.

Private Space

• Independent vault: Files moved into the private space are isolated from the normal list.
• Hideable entry: The private space entry can be hidden in settings so others won't notice it.
• Discreet entry: Long-press and swipe down on the home screen to invoke the private space, leaving no trace in the UI.

File Manager

• Junk cleanup: Scan caches, leftovers, and invalid files, and free up space with one tap.
• Similar-file filtering: Identify duplicate and near-duplicate images/files by content / hash for batch cleanup.
• Image / video compression: Built-in compression to shrink multimedia size and save storage, with native (CMake) acceleration.

Remote Files & Sharing

• Remote protocol clients: Supports FTP(S), SMB, WebDAV(S), natively managing remote storage (browse / download / upload / delete).
• FTP server: Launch an FTP / FTPS service on the device with one tap (apache-ftpserver, FTPS uses a self-signed BKS certificate) to share files over the local network.

Built-in Viewers

• Image viewer: Based on Coil 3 + Telephoto, supports zoom and subsampled tiled decoding so large images don't lag.
• Video / audio player: Based on Media3 (ExoPlayer), supports common formats.
• Reader: Built-in document reading capability for quick preview of text and common documents.

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Navigation & Tasks

Navigation Stack (Navigation 3)

• Type-safe routing: Built on AndroidX Navigation 3 (the latest Jetpack navigation framework), with strongly typed NavKey throughout,告别 string-routing typos.
• Multi-back-stack: Each bottom Tab independently preserves deep navigation state (subdirectory breadcrumbs, scroll position); switching Tabs and back loses no position.
• Directory as the real path stack: File browsing is maintained by DirectoryNavigator as a single source of truth — an "ancestor chain" — so the breadcrumb always reflects the real hierarchy, and popTo jumps back to any upper level with one tap.
• Unified back entry: The system back gesture and the top-bar back button share the same onBack logic (UnifiedBack), avoiding the regression of "two inconsistent back behaviors".
• Safe root boundary: Reaching the storage volume root is the floor; long-pressing the breadcrumb "root directory" switches the storage volume (internal / external SD / root), without accidentally leaving the volume.

Task Panel (FileJobManager)

• Background task engine: Copy / move / delete / compress / extract / private-space import-export all go through FileJobManager, decoupled from the UI lifecycle — tasks keep running in the background even after you close the page.
• Parallel multitasking: Up to 3 concurrent worker threads pull tasks from the queue; extras are queued automatically and executed in submission order, without blocking each other.
• Always-on progress panel: A small task panel (FileJobPanel) stays in the file page, showing each task's progress, speed, ETA, and queue position in real time; a system notification also shows progress, visible even on the lock screen.
• Smart core scheduling for archive ops: ArchiveCpuGovernor allocates a unified CPU-core budget for all heavy archive operations (reserving 1 core for the system). 7Z uses a native 7zr subprocess and auto-injects -mmt (splitting threads across remaining cores); single-core engines like ZIP / TAR only register a slot, avoiding over-subscription from "7Z eating all cores + multiple ZIPs each taking 1 core". Multiple formats can run in parallel without slowing each other down.
• Cancelable / retryable: Cancel a single task or all at once; on a wrong password it enters a "waiting for password" suspended state — re-enter to continue, without the whole batch failing.

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Acknowledgements

The design and implementation of this project draw heavily on the following excellent open-source projects, to which we extend our gratitude:

• Material Files: The main reference for the navigation architecture — the TrailData path chain (NaviState), the data-only FileItem model (FileInfoData), the WebDAV / FTP design, and the idea of driving canNavigateUpBreadcrumb with the back key all originate here.
• Prism File Explorer: The source of many interaction and implementation ideas, including the video player state, the text editor toolbar (undo / redo / save / more menu), stable secondary sorting and naturalCompare, list-state-by-path mapping, and the ActionCard design of the "open source" page.
• Amaze File Manager: Reference for the file task queue model (the parallel queue of FileJobManager), deep search, history clearing, and the FTP timeout default.
• Ghost Commander: The design idea of persisting credentials as ciphertext (plaintext exists only in memory for an instant, never on disk).
• Sandbox (AOSP packages_apps_Sandbox): The source of the private space SecurityType (PIN mechanism).

Thanks also to the following open-source libraries and components: zip4j, Apache Commons Compress, libsu, Shizuku, SMBJ, sardine-android (WebDAV), Media3 (ExoPlayer), Coil 3 + Telephoto, Apache FtpServer, and AndroidX (Hilt / Navigation 3 / Compose / DataStore, etc.).