Android debugging in VS Code and Windows Subsystem for Linux (WSL)

5 min readNov 6, 2020

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The Windows Subsystem for Linux (WSL) has been a game-changer for software development on Windows. Paired with VS Code and its remote development feature, it is a powerful alternative to the traditional MacOS and Linux development environments. Having all my projects in VS Code within WSL has been a great development experience.

Recently, working with BookSloth on their Android app, I wanted to run and debug the app locally. One option was using Android Studio, but that meant giving up the uniformity of my development process. So I started setting up the project and the Android SDK in the WSL only. The problem came when running the emulator. WSL does not support virtualization out-of-the-box, and adding virtualization required experimental configurations. The solution was to run the emulator on the Windows host and bridging it to the WSL setup.

With this configuration, you’ll be able to do all your development inside the WSL with VS Code and debug your application on an emulator running on the Windows host.

Requirements

Android SDK Command Line Tools
Android VS Code extension
Code project is cloned inside the WSL file system

Setup is required for both the Windows host and the WSL in order to make this work. This was set up using the Ubuntu 20.04 for the WSL machine and probably works for other Linux distros. Commands for Windows are being run in PowerShell and bash in the WSL.

Feel free to customize names or directory locations in the following steps where necessarily to meet your requirements or accommodate them to your existing development environment.

SDK Setup

WSL and Windows — Create a directory called android wherever you specify your SDK files
WSL and Windows — Download the latest Command Line Tools from the link above and extract the .zip
WSL and Windows — Move cmdline-tools into the android directory
WSL and Windows — Move contents of cmdline-tools into a sub-folder called latest (assuming you’re using the latest version of the command line tools)
WSL and Windows — Configure the PATH location of the sdkmanager and other SDK tools:

Windows PATH

path\to\cmdline-tools\latest\bin
path\to\platform-tools
path\to\emulator

WSL Bash:

WSL — Install the build and platform tools for the target version. Check the app/build.gradle project file for the targetSdkVersion

sdkmanager "build-tools;<TARGET_VERSION>" "platforms;android-<TARGET_VERSION>" "platform-tools"

Windows — Install the platform and emulator tools and packages for the target version

sdkmanager "platforms;android-<TARGET_VERSION>" "platform-tools" "emulator"

WSL and Windows — Accept SDK licenses

sdkmanager — licenses

Emulator Setup

Windows — Download an Android Virtual Device (AVD) image

sdkmanager "system-images;android-<TARGET_VESION>;default;x86_64"

Windows — Create a new AVD using the avdmanager

avdmanager create avd -name [AVDName] -package "[PACKAGE]" -device "[DEVICENAME]"

Windows — Add Firewall Rules to allow port traffic to and from WSL. Click here and here for more information on how to do so.

WSL — Install the Android VS Code extension by adelphes

WSL — Change the host IP address in the adbSocket property in the .vscode/launch.json to the WSL host IP. This can be obtained using cat /etc/resolv.conf | grep nameserver | cut -d' '-f2

"adbSocket": "[WSL_HOST_IP]:5037"

Debugging

WSL — Build your project
Windows — Start the Android emulator

emulator -avd [AVDName]

Windows — Open port 5037 communication from Windows host to WSL

adb -a -P 5037 nodaemon server

WSL — Start debugging in VS Code by running the debug configuration created by the Android extension. Happy debugging!

Common Errors

Emulator — Dev computer keyboard not working in emulator

Go to path\to\.android\avd\AVDName.avd
In the config.ini file, change hw.keyboard to yes

Debug — Launch failed: ADBSocket Socket connect failed.

Check your debug launcher and emulator device are using the same port (defaulted to 5037)

Debug — Launch failed: No devices are connected

Check emulator is running
Check adb server is running in WSL
Check you installed the SAME version of adb on both Windows and WSL using adb - - version
Check you are using the adb command installed in the WSL. To avoid PATH mix-ups in WSL, disable importing your Windows PATH into WSL by creating the file /etc/wsl.conf/ and adding the lines

[interop]
enabled=false
appendWindowsPath=false

Check adb -a -P 5037 nodaemon server is running in Windows host
Check in Windows host Firewall is not blocking traffic from adb or WSL
Check the launch configuration has the correct WSL host IP and port in the adbSocket property