Android context in multiplatform project

Question

I wonder if is possible to access the Android context application in androidMain sourceSets with the kotlin-multiplatform plugin.

Here is the build.gradle file

apply plugin: 'kotlin-multiplatform'

kotlin {
    targets {
        final def iOSTarget = System.getenv('SDK_NAME')?.startsWith("iphoneos")   \
                                ? presets.iosArm64 : presets.iosX64

        fromPreset(iOSTarget, 'iOS') {
            compilations.main.outputKinds('FRAMEWORK')
        }

        fromPreset(presets.jvm, 'android')
    }

    sourceSets {

        commonMain {
            kotlin.srcDir('src')
            dependencies {
                implementation "org.jetbrains.kotlin:kotlin-stdlib-common:$kotlin_version"
                // coroutine
                implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core-common:1.1.0"
            }
        }

        androidMain {
            dependencies {
                implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
                // Timber
                implementation "com.jakewharton.timber:timber:$timber_version"
                // coroutine
                implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.1.0"
            }
        }
    }
}

I have tried add the 'com.android.application' plugin into androidMain source, but the sync fails.

Thanks in advance

Answer 1

Yes, you can.

In your build.gradle file you are not targeting android as such (presets.android) but the jvm (presets.jvm) and calling it android.

As it is now, what your build will generated is a JAR file not an aar file.

If you want to target android you have also to use the android gradle plugin. To be able to use the android framework from the androidMain folder, update your build.gradle file. Below an example:

apply plugin: 'org.jetbrains.kotlin.multiplatform'
apply plugin: 'com.android.library'

android {
    compileSdkVersion 28
    defaultConfig {
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName '1.0'
    }
    buildTypes {
        release {
            minifyEnabled false
        }
    }

        // By default the android gradle plugin expects to find the kotlin source files in 
        // the folder `main` and the test in the folder `test`. This is to be able place 
        // the source code files inside androidMain and androidTest folders
    sourceSets {
        main {
            manifest.srcFile 'src/androidMain/AndroidManifest.xml'
            java.srcDirs = ['src/androidMain/kotlin']
            res.srcDirs = ['src/androidMain/res']
        }
        test {
            java.srcDirs = ['src/androidTest/kotlin']
            res.srcDirs = ['src/androidTest/res']
        }
    }
}

dependencies {
    implementation "com.jakewharton.timber:timber:$timber_version
}

kotlin {
    targets {
        final def iOSTarget = System.getenv('SDK_NAME')?.startsWith("iphoneos")   \
                                ? presets.iosArm64 : presets.iosX64

        fromPreset(iOSTarget, 'iOS') {
            compilations.main.outputKinds('FRAMEWORK')
        }

        fromPreset(presets.android, 'android')
    }
    sourceSets {
        commonMain {
            dependencies {
                implementation "org.jetbrains.kotlin:kotlin-stdlib-common:$kotlin_version"
                // coroutine
                implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core-common:1.1.0"
            }
        }
        androidMain {
            dependencies {
                api "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
            }
        }
    }
}

task buildiOSFramework(type: Sync) {

    final File frameworkDir = new File(buildDir, "xcode-frameworks")
    final String mode = project.findProperty("XCODE_CONFIGURATION")?.toUpperCase() ?: 'DEBUG'

    inputs.property "mode", mode
    dependsOn kotlin.targets.iOS.compilations.main.linkTaskName("FRAMEWORK", mode)

    from { kotlin.targets.iOS.compilations.main.getBinary("FRAMEWORK", mode).parentFile }
    into frameworkDir

    doLast {
        new File(frameworkDir, 'gradlew').with {
            text = "#!/bin/bash\nexport 'JAVA_HOME=${System.getProperty("java.home")}'\ncd '${rootProject.rootDir}'\n./gradlew \$@\n"
            setExecutable(true)
        }
    }
}