ViewModel Compose Multiplatform and Koject

Koject integration with Kotlin Multiplatform ViewModel and Jetpack Compose Multiplatform.

Koject is a DI Container Library for Kolin Multiplatform using KSP. For more information check out the Koject documentation.

The kmp-viewmodel-koject-compose artifact provides the integration of kmp-viewmodel-compose and Koject, helps us to retrieve ViewModel in @Composable functions from the Koject DI container without manually dependency injection.

1. Add dependency

• Add mavenCentral() to repositories list in build.gradle.kts/settings.gradle.kts.

// settings.gradle.kts
dependencyResolutionManagement {
  [...]
  repositories {
    mavenCentral()
    [...]
  }
}

• Add dependency to build.gradle.kts of your shared module.

// build.gradle.kts
kotlin {
  sourceSets {
    val commonMain by getting {
      dependencies {
        implementation("io.github.hoc081098:kmp-viewmodel-koject-compose:0.8.0")

        // NOTE: You can add `koject-core` dependency to your project to specify the version of Koject.
        // For more information check out the [Koject Setup documentation](https://mori-atsushi.github.io/koject/docs/setup#multiplatform).
        implementation("com.moriatsushi.koject:koject-core:${kojectVersion}")
      }
    }
  }
}

dependencies {
  val processor = "com.moriatsushi.koject:koject-processor-app:${kojectVersion}"

  fun String.capitalizeUS() = replaceFirstChar {
    if (it.isLowerCase()) {
      it.titlecase(Locale.US)
    } else {
      it.toString()
    }
  }

  kotlin
    .targets
    .names
    .map { it.capitalizeUS() }
    .forEach { target ->
      val targetConfigSuffix = if (target == "Metadata") "CommonMainMetadata" else target
      add("ksp$targetConfigSuffix", processor)
    }
}

Snapshots of the development version are available in Sonatype's snapshots repository.

// settings.gradle.kts
dependencyResolutionManagement {
  repositoriesMode.set(RepositoriesMode.PREFER_PROJECT)
  repositories {
    maven(url = "https://s01.oss.sonatype.org/content/repositories/snapshots/")
    [...]
  }
}

// build.gradle.kts
dependencies {
  implementation("io.github.hoc081098:kmp-viewmodel-koject-compose:0.7.2-SNAPSHOT")
}

[!NOTE] Make sure to setup KSP in your project. For more information check out the Koject Setup documentation.

2. Add @Provides and @ViewModelComponent to ViewModel

import com.hoc081098.kmp.viewmodel.ViewModel
import com.hoc081098.kmp.viewmodel.SavedStateHandle
import com.hoc081098.kmp.viewmodel.koject.ViewModelComponent
import com.moriatsushi.koject.Provides
import com.moriatsushi.koject.Singleton

@Provides
@Singleton
class MyRepository

@Provides
@ViewModelComponent // <-- To inject SavedStateHandle
class MyViewModel(
  val myRepository: MyRepository,
  val savedStateHandle: SavedStateHandle,
) : ViewModel() {
  // ...
}

[!NOTE] Make sure to start Koject in your project, for example:

Koject.start()

For more information check out the Start Koject documentation.

3. Retrieve ViewModel in @Composables function via kojectKmpViewModel function

import com.hoc081098.kmp.viewmodel.koject.compose.kojectKmpViewModel

@Composable
fun MyScreen(
  viewModel: MyViewModel = kojectKmpViewModel(),
) {
  // ...
}