android-tiling-wm

An i3/Hyprland-style tiling window manager for Android 16+ phones. No root required.

What is this?

Android 16 supports freeform windowing on the phone's primary display — complete with native caption bars (title bar, minimize/maximize/close, drag-to-move, resize handles). This project uses that capability to tile app windows automatically, like a desktop tiling WM.

Key discovery: Android 16 renders native window chrome on freeform windows on display 0. No LSPosed hooks, no custom ROM, no root. Just freeform mode + window resizing.

Current State

Proof of concept — an ADB-based shell script (tile.sh) that demonstrates tiling works. Tested on Pixel 7a running Android 16 (API 36).

The roadmap is a standalone Android app using Shizuku for privileged window management + AccessibilityService for window event tracking.

Quick Start

Prerequisites

• Android 16+ device
• ADB connected via USB or WiFi
• adb in your PATH

Setup

# Enable freeform windowing on the device
./scripts/tile.sh setup

# Launch some apps in freeform mode
./scripts/tile.sh launch com.android.settings
./scripts/tile.sh launch com.android.chrome
./scripts/tile.sh launch com.google.android.apps.messaging

# Tile them
./scripts/tile.sh tile

Commands

Command	Description
tile.sh setup	Enable freeform windowing settings on device
tile.sh launch <pkg>	Launch an app in freeform mode
tile.sh tile	Tile all visible freeform windows
tile.sh list	List visible freeform tasks
tile.sh layout <name>	Switch layout (master-stack, columns, monocle)
tile.sh close <taskId>	Close a task and re-tile remaining
tile.sh reset	Return all tasks to fullscreen
tile.sh screenshot	Capture and pull screenshot to /tmp/

Layouts

• master-stack (default) — One master pane on the left (55% width), remaining apps stacked vertically on the right
• columns — Equal-width vertical columns
• monocle — All windows fullscreen, last one on top

Environment Variables

Variable	Default	Description
TILE_LAYOUT	master-stack	Default layout
TILE_MASTER_RATIO	55	Master pane width as percentage

How It Works

1. am start --windowingMode 5 launches apps in freeform mode on the phone screen
2. am task resize <taskId> <left> <top> <right> <bottom> positions each window
3. Android 16 automatically renders native caption bars (drag handle, minimize, maximize, close) on freeform windows

That's it. The window management is built into Android — we're just driving it.

Roadmap

Phase 1: Tiling Engine (Standalone App)

• Shizuku UserService with resizeTask() + getTasks() + setTaskWindowingMode()
• AccessibilityService for window open/close/focus events
• Master+stack layout algorithm
• Event pipeline: accessibility event → debounce → get tasks → calculate layout → resize

Phase 2: Taskbar Fork Integration

• Fork Taskbar (Apache 2.0)
• Replace fire-and-forget launch with tiling-aware placement
• Layout switching UI
• Persistent tiling state

Phase 3: Polish

• Additional layouts (BSP, spiral)
• Keyboard shortcuts / gesture controls
• Per-app floating exceptions
• Gap/padding configuration

Requirements for the App (Future)

• Android 16+ (API 36)
• Shizuku running (no root needed — wireless ADB pairing works)
• Accessibility service enabled

Technical Details

See docs/research-spec.md for the full research spec, including:

• AOSP source analysis of the freeform decoration system
• Shizuku API surface (IActivityTaskManager methods)
• Taskbar codebase analysis and fork hook points
• Tiling engine architecture with AccessibilityService bridging
• Known gotchas and limitations

Device Settings

The setup command enables these (all persist across reboots):

Settings.Global.enable_freeform_support = 1
Settings.Global.force_resizable_activities = 1
Settings.Global.enable_non_resizable_multi_window = 1

Note: desktop_mode and force_desktop_mode_on_external_displays are intentionally not set — they lock Pixel Launcher to landscape and aren't needed for freeform windowing on the phone's primary display.

License

Apache 2.0