Using Android's own build.

kobalt/src/Build.kt

@@ -67,6 +67,8 @@ val kobalt = kotlinProject(wrapper) {
                 "org.jetbrains.dokka:dokka-fatjar:0.9.2",
                 "org.jetbrains.kotlinx:kotlinx.dom:0.0.4",
 
+                "com.android.tools.build:builder:1.5.0",
+
                 "com.beust:jcommander:1.48",
                 "com.squareup.okhttp:okhttp:2.5.0",
                 "org.jsoup:jsoup:1.8.3",

src/main/kotlin/com/beust/kobalt/plugin/android/AndroidBuild.kt

@@ -0,0 +1,126 @@
+package com.beust.kobalt.plugin.android
+
+import com.android.builder.core.AndroidBuilder
+import com.android.builder.core.ErrorReporter
+import com.android.builder.core.LibraryRequest
+import com.android.builder.model.SyncIssue
+import com.android.builder.sdk.DefaultSdkLoader
+import com.android.builder.sdk.SdkLoader
+import com.android.ide.common.blame.Message
+import com.android.ide.common.process.*
+import com.android.ide.common.res2.*
+import com.android.sdklib.repository.FullRevision
+import com.android.utils.StdLogger
+import com.beust.kobalt.homeDir
+import com.beust.kobalt.misc.KFiles
+import com.beust.kobalt.misc.log
+import java.io.File
+
+class KobaltProcessResult : ProcessResult {
+    override fun getExitValue(): Int {
+        return 0
+    }
+
+    override fun assertNormalExitValue(): ProcessResult? {
+        throw UnsupportedOperationException()
+    }
+
+    override fun rethrowFailure(): ProcessResult? {
+        throw UnsupportedOperationException()
+    }
+}
+
+class KobaltJavaProcessExecutor : JavaProcessExecutor {
+    override fun execute(javaProcessInfo: JavaProcessInfo?, processOutputHandler: ProcessOutputHandler?)
+            : ProcessResult? {
+        log(1, "Executing " + javaProcessInfo!!)
+        return KobaltProcessResult()
+    }
+}
+
+class KobaltProcessOutputHandler : BaseProcessOutputHandler() {
+    override fun handleOutput(processOutput: ProcessOutput) =
+            log(1, "AndroidBuild output" + processOutput.standardOutput)
+}
+
+class KobaltErrorReporter : ErrorReporter(ErrorReporter.EvaluationMode.STANDARD) {
+    override fun handleSyncError(data: String?, type: Int, msg: String?): SyncIssue? {
+        throw UnsupportedOperationException()
+    }
+
+    override fun receiveMessage(message: Message?) {
+        throw UnsupportedOperationException()
+    }
+}
+
+class ProjectLayout {
+    val mergeBlame: File? = null
+    val publicText: File? = null
+
+}
+
+class AndroidBuild {
+    val annotationsJar = File("/Users/beust/adt-bundle-mac-x86_64-20140702/sdk/tools/lib/annotations.jar")
+    val adb = File("/Users/beust/adt-bundle-mac-x86_64-20140702/sdk/platform-tools/adb")
+
+    fun run() {
+        val logger = StdLogger(StdLogger.Level.VERBOSE)
+        val processExecutor = DefaultProcessExecutor(logger)
+        val javaProcessExecutor = KobaltJavaProcessExecutor()
+        val sdkLoader : SdkLoader = DefaultSdkLoader.getLoader(File("/Users/beust/adt-bundle-mac-x86_64-20140702/sdk"))
+        val repositories = sdkLoader.repositories
+        val sdkInfo = sdkLoader.getSdkInfo(logger)
+        val androidBuilder = AndroidBuilder("com.beust.kobalt", "Cedric Beust",
+                processExecutor,
+                javaProcessExecutor,
+                KobaltErrorReporter(),
+                logger,
+                true /* verbose */)
+
+        val processOutputHandler = KobaltProcessOutputHandler()
+        val dir : String = KFiles.joinDir(homeDir("kotlin/kobalt-examples/android-flavors"))
+        val outputDir = KFiles.joinDir(dir, "kobaltBuild", "intermediates", "res", "merged", "pro",
+                "debug")
+        val layout = ProjectLayout()
+        val preprocessor = NoOpResourcePreprocessor()
+
+        // AndroidTargetHash.getTargetHashString(target))
+        val targetHash = "android-22"
+        val buildToolsRevision = FullRevision(23, 0, 1)
+        val libraryRequests = arrayListOf<LibraryRequest>()
+        androidBuilder.setTargetInfo(sdkLoader.getSdkInfo(logger),
+                sdkLoader.getTargetInfo(targetHash, buildToolsRevision, logger),
+                libraryRequests)
+
+        val writer = MergedResourceWriter(File(outputDir),
+                androidBuilder.getAaptCruncher(processOutputHandler),
+                false /* don't crunch */,
+                false /* don't process 9patch */,
+                layout.publicText,
+                layout.mergeBlame,
+                preprocessor)
+        println("Repositories: $repositories")
+        val target = androidBuilder.target
+        val dxJar = androidBuilder.dxJar
+        val resourceMerger = ResourceMerger()
+
+        //
+        // Resources
+        //
+        listOf("main", "free", "release").forEach {
+            val path = "$dir/src/$it/res"
+            val set = ResourceSet(path)
+            set.addSource(File(path))
+            set.loadFromFiles(logger)
+
+            val generated = GeneratedResourceSet(set)
+            set.setGeneratedSet(generated)
+
+            resourceMerger.addDataSet(set)
+        }
+
+
+        resourceMerger.mergeData(writer, true)
+        println("")
+    }
+}