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Overview

TechSales uses Gradle’s version catalog feature for centralized dependency management. All dependencies are declared in gradle/libs.versions.toml and referenced type-safely in build files.

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App Dependencies

The application module declares its dependencies in app/build.gradle.kts:
app/build.gradle.kts
dependencies {
    implementation(libs.appcompat)
    implementation(libs.material)
    implementation(libs.activity)
    implementation(libs.constraintlayout)
    testImplementation(libs.junit)
    androidTestImplementation(libs.ext.junit)
    androidTestImplementation(libs.espresso.core)
}

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Core Dependencies

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AndroidX AppCompat

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libs.appcompat
Library
required
Provides backward-compatible versions of Android framework APIs.Version: 1.6.1
Group: androidx.appcompat
Artifact: appcompat
implementation(libs.appcompat)
Key Features:
  • Material Design components
  • ActionBar and Toolbar support
  • AppCompatActivity and theme support
  • Vector drawables on older Android versions
AppCompat is essential for maintaining consistency across Android versions. It backports newer UI components to older devices.

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Material Design Components

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libs.material
Library
required
Google’s Material Design component library for Android.Version: 1.10.0
Group: com.google.android.material
Artifact: material
implementation(libs.material)
Key Features:
  • Material Design 3 components
  • Bottom sheets, navigation drawers, cards
  • Floating action buttons (FAB)
  • Text fields and input layouts
  • Snackbars and dialogs

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AndroidX Activity

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libs.activity
Library
required
Modern activity handling with result contracts and ViewModels.Version: 1.8.0
Group: androidx.activity
Artifact: activity
implementation(libs.activity)
Key Features:
  • Activity Result API
  • ComponentActivity base class
  • OnBackPressedDispatcher
  • Integration with ViewModels and Lifecycle

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ConstraintLayout

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libs.constraintlayout
Library
required
Flexible layout manager for creating responsive UIs.Version: 2.1.4
Group: androidx.constraintlayout
Artifact: constraintlayout
implementation(libs.constraintlayout)
Key Features:
  • Flat view hierarchy for better performance
  • Responsive layouts without nested ViewGroups
  • Constraint-based positioning
  • Guidelines, barriers, and chains
ConstraintLayout is the recommended layout manager for modern Android apps. It reduces layout nesting and improves performance.

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Test Dependencies

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JUnit 4

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libs.junit
Library
Standard unit testing framework for Java/Kotlin.Version: 4.13.2
Group: junit
Artifact: junit
Configuration: testImplementation
testImplementation(libs.junit)
Use Cases:
  • Unit tests for business logic
  • ViewModel testing
  • Repository and data source tests
  • Utility function tests

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AndroidX JUnit Extension

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libs.ext.junit
Library
AndroidX test runner with JUnit 4 integration.Version: 1.1.5
Group: androidx.test.ext
Artifact: junit
Configuration: androidTestImplementation
androidTestImplementation(libs.ext.junit)
Use Cases:
  • Instrumented tests that require Android context
  • Activity and Fragment testing
  • Integration tests

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Espresso

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libs.espresso.core
Library
UI testing framework for Android.Version: 3.5.1
Group: androidx.test.espresso
Artifact: espresso-core
Configuration: androidTestImplementation
androidTestImplementation(libs.espresso.core)
Use Cases:
  • UI interaction testing
  • View matching and assertions
  • Automated user flow testing
Espresso tests run on real devices or emulators and can interact with your app’s UI like a real user would.

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Version Catalog Structure

The version catalog is defined in gradle/libs.versions.toml:
gradle/libs.versions.toml
[versions]
agp = "9.0.1"
junit = "4.13.2"
junitVersion = "1.1.5"
espressoCore = "3.5.1"
appcompat = "1.6.1"
material = "1.10.0"
activity = "1.8.0"
constraintlayout = "2.1.4"

[libraries]
junit = { group = "junit", name = "junit", version.ref = "junit" }
ext-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }
appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
material = { group = "com.google.android.material", name = "material", version.ref = "material" }
activity = { group = "androidx.activity", name = "activity", version.ref = "activity" }
constraintlayout = { group = "androidx.constraintlayout", name = "constraintlayout", version.ref = "constraintlayout" }

[plugins]
android-application = { id = "com.android.application", version.ref = "agp" }

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Structure Breakdown

[versions] Section:
  • Declares version numbers as variables
  • Referenced using version.ref in library declarations
  • Single source of truth for versions
[libraries] Section:
  • Declares dependencies with Maven coordinates
  • Format: { group = "...", name = "...", version.ref = "..." }
  • Accessed in build files as libs.libraryName
[plugins] Section:
  • Declares Gradle plugins
  • Accessed as libs.plugins.pluginName

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Dependency Configurations

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Implementation

implementation(libs.appcompat)
  • Used for dependencies required at runtime
  • Not exposed to consumers (in library modules)
  • Faster compilation than api

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TestImplementation

testImplementation(libs.junit)
  • Used for unit test dependencies
  • Only available in test source set
  • Not included in APK

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AndroidTestImplementation

androidTestImplementation(libs.espresso.core)
  • Used for instrumented test dependencies
  • Only available in androidTest source set
  • Not included in production APK
Choose the most restrictive configuration possible. Using testImplementation instead of implementation for test-only dependencies reduces APK size.

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Adding New Dependencies

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Step 1: Add Version to Catalog

Edit gradle/libs.versions.toml: 
[versions]
# Existing versions...
retrofit = "2.9.0"

[libraries]
# Existing libraries...
retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
retrofit-gson = { group = "com.squareup.retrofit2", name = "converter-gson", version.ref = "retrofit" }

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Step 2: Add to Build File

Edit app/build.gradle.kts: 
dependencies {
    // Existing dependencies...
    implementation(libs.retrofit)
    implementation(libs.retrofit.gson)
}

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Step 3: Sync Project

Click “Sync Now” in Android Studio or run: 
./gradlew build
Android Studio provides auto-completion for version catalog entries. Type libs. to see available dependencies.

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Updating Dependencies

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Manual Updates

  1. Edit version in gradle/libs.versions.toml
  2. Sync the project
  3. Test thoroughly

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Checking for Updates

Use the Gradle Versions Plugin:
build.gradle.kts
plugins {
    id("com.github.ben-manes.versions") version "0.51.0"
}
Then run: 
./gradlew dependencyUpdates
Always test your app after updating dependencies, especially major version updates. Check release notes for breaking changes.

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Dependency Management Best Practices

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1. Use Version Catalogs

// Good - Type-safe and centralized
implementation(libs.appcompat)

// Avoid - String literals scattered across files
implementation("androidx.appcompat:appcompat:1.6.1")

[versions]
retrofit = "2.9.0"

[libraries]
retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
retrofit-gson = { group = "com.squareup.retrofit2", name = "converter-gson", version.ref = "retrofit" }

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3. Use Specific Configurations

// Good - Minimizes APK size
testImplementation(libs.junit)

// Avoid - Includes test dependency in production
implementation(libs.junit)

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4. Avoid Dynamic Versions

# Good - Pinned version
appcompat = "1.6.1"

# Avoid - Unpredictable builds
appcompat = "1.6.+"
appcompat = "latest.release"

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5. Document Custom Dependencies

Add comments in libs.versions.toml for non-standard dependencies: 
[libraries]
# Custom analytics SDK from internal repository
analytics-sdk = { group = "com.company.internal", name = "analytics", version.ref = "analyticsSdk" }

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Viewing Dependency Tree

To see all dependencies and their transitive dependencies: 
# All configurations
./gradlew :app:dependencies

# Specific configuration
./gradlew :app:dependencies --configuration releaseRuntimeClasspath

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Resolving Dependency Conflicts

When multiple dependencies require different versions of the same library: 
dependencies {
    implementation(libs.appcompat)
    
    // Force specific version
    constraints {
        implementation("org.jetbrains.kotlin:kotlin-stdlib:1.9.0") {
            because("standardize Kotlin version across all dependencies")
        }
    }
}
Forcing dependency versions can lead to compatibility issues. Only use this when necessary and test thoroughly.

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Common Dependencies to Add

Here are commonly added dependencies for Android apps: 
[versions]
retrofit = "2.9.0"
okhttp = "4.12.0"

[libraries]
retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
retrofit-gson = { group = "com.squareup.retrofit2", name = "converter-gson", version.ref = "retrofit" }
okhttp = { group = "com.squareup.okhttp3", name = "okhttp", version.ref = "okhttp" }
okhttp-logging = { group = "com.squareup.okhttp3", name = "logging-interceptor", version.ref = "okhttp" }

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