Narasimha-scandGitHub
147355b76a
On an incoming call the desktop window blinked continuously (FileNotFoundException
from SoundPlayer.start writing into a missing ...\Temp\simplex).
Root cause: Files.desktop top-level val initializers run in any process that
touches the facade class, including a transient second instance (which reaches
acquireSingleInstance -> dataDir). Two of them deleted shared state used by the
running primary:
- tmpDir had .also { deleteOnExit() } - the second instance's normal exit deleted
...\Temp\simplex, so the primary then failed to write call sounds/recordings.
- preferencesTmpDir had .also { deleteRecursively() } - the second instance's
<clinit> wiped configPath\tmp (same anti-pattern, firing even earlier).
Make both declarations pure and do the destructive cleanup in Main, past the
single-instance check, so only the owning instance performs it (preferencesTmpDir
kept early, before any settings write). The remaining val-initializer side effects
are idempotent creations (mkdirs) that destroy nothing and are left in place.
Android App Development
This is a guide to contributing to the develop of the SimpleX android and desktop apps.
Project Overview
This is the Kotlin Multiplatform (KMP) mobile and desktop client for SimpleX Chat, sharing code between Android and Desktop (JVM) platforms using Compose Multiplatform for UI.
Build Commands
# Android debug APK
./gradlew assembleDebug
# Android release APK
./gradlew assembleRelease
# Desktop distribution (current OS)
./gradlew :desktop:packageDistributionForCurrentOS
# Run desktop/JVM tests
./gradlew desktopTest
# Run Android instrumented tests (requires connected device/emulator)
./gradlew connectedAndroidTest
# Build native libraries for all platforms
./gradlew common:cmakeBuild -PcrossCompile
# Clean build
./gradlew clean
Architecture
Module Structure
common/- Shared code (Compose UI, models, business logic)src/commonMain/- Cross-platform codesrc/androidMain/- Android-specific implementationssrc/desktopMain/- Desktop-specific implementations
android/- Android app containerdesktop/- Desktop JVM app container
Key Components (common/src/commonMain/kotlin/chat/simplex/common/)
model/ChatModel.kt- Main state container with reactive properties (MutableState, MutableStateFlow)model/SimpleXAPI.kt- API bindings to Haskell core library via FFIplatform/Core.kt- FFI interface to nativelibapplibraryplatform/- Platform abstraction layer (expect/actual pattern for Android/Desktop specifics)views/- Compose UI screens organized by feature (chat, chatlist, call, usersettings, etc.)ui/theme/- Design system (colors, typography, shapes)
Native Integration
The app calls into a Haskell core library via JNI/FFI:
- CMake builds in
common/src/commonMain/cpp/android/andcpp/desktop/ - Cross-compilation toolchains in
cpp/toolchains/ - Built libraries go to
cpp/desktop/libs/(organized by platform)
Configuration
local.properties (create from local.properties.example)
compression.level=0 # APK compression (0-9)
enable_debuggable=true # Debug mode
application_id.suffix=.debug # Multiple app instances on same device
app.name=SimpleX Debug # App name for debug builds
gradle.properties
Contains versions (Kotlin, Compose, AGP) and app version info. Key settings:
kotlin.jvm.target=11database.backend=sqlite(orpostgres)
Testing
Tests are in:
common/src/commonTest/kotlin/- Cross-platform testscommon/src/desktopTest/kotlin/- Desktop-specific tests (run with./gradlew desktopTest)android/src/androidTest/- Android instrumented tests
Resources & Localization
- String resources:
common/src/commonMain/resources/MR/base/strings.xml+ 21 language variants - Uses Moko Resources (
dev.icerock.moko:resources) for cross-platform resource management - The
adjustFormattinggradle task validates string resources during build
Platform-Specific Notes
Android
- Min SDK 26, Target SDK 35
- NDK 23.1.7779620
- Supports ABI splits:
arm64-v8a,armeabi-v7a - Deep linking requires SHA certificate fingerprint in
assetlinks.json(see README.md)
Desktop
- Distributions: DMG (macOS), MSI/EXE (Windows), DEB (Linux)
- Mac signing/notarization configured via
local.properties - Video playback uses VLCJ
Gotchas
SHA Signature for verification for app links/deep links
In order for the SimpleX app to be automatically adopted for opening links from https://simplex.chat the SHA certificate fingerprint for the App installed on the phone must be in the hosted assetlinks.json file on simplex.chat.
The accepted fingerprints are in the sha256_cert_fingerprints list.
To find your SHA certificate fingerprint perform the following steps.
- Build and install your development version of the app as usual
- From the terminal in Android studio run
adb shell pm get-app-links chat.simplex.app - Copy the signature listed in
signaturesin the result - Add your signature to assetlinks.json in the website repo and make a PR. On approval, wait a few minutes for the changes to propagate to the public website and then you should be able to verify SimpleX.
More information is available here. If there is no response when running the pm get-app-links command, the intents in AndroidManifest.xml are likely misspecified. A verification attempt can be triggered using adb shell pm verify-app-links --re-verify chat.simplex.app.
Note that this is not an issue for the app store build of the app as this is signed with our app store credentials and thus there is a stable signature over users. Developers do not have general access to these credentials for development and testing.
Adding icons
-
Find a Material symbol in Rounded category.
-
Set weight to 400, grade to -25 and size to 48px.
-
Click on the icon, choose Android and download XML file.
-
Update the color to black (#FF000000) and the size to "24.dp", as in other icons.
For example, this is add reaction icon.