fix: Allow building React Native from source (microsoft#131)

android/app/build.gradle

@@ -5,13 +5,13 @@ buildscript {
     apply from: "$buildscriptDir/../test-app-util.gradle"
 
     repositories {
-        jcenter()
         google()
+        jcenter()
     }
 
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
-        classpath "com.android.tools.build:gradle:3.6.1"
+        classpath "com.android.tools.build:gradle:3.6.2"
     }
 }
 
@@ -20,8 +20,8 @@ repositories {
         url("${findNodeModulesPath(rootDir, "react-native")}/android")
     }
 
-    jcenter()
     google()
+    jcenter()
 }
 
 apply plugin: "com.android.application"
@@ -35,8 +35,8 @@ apply from: file("${testAppDir}/test-app.gradle")
 applyTestAppModule(project, "com.sample")
 
 project.ext.react = [
-  enableFlipper: getFlipperVersion(rootDir),
-  enableHermes: true,
+    enableFlipper: getFlipperVersion(rootDir),
+    enableHermes: true,
 ]
 
 android {
@@ -87,7 +87,11 @@ dependencies {
     releaseImplementation files("$hermesPath/hermes-release.aar")
     debugImplementation files("$hermesPath/hermes-debug.aar")
 
-    implementation "com.facebook.react:react-native:+"
+    if (buildReactNativeFromSource(rootDir)) {
+        implementation project(':ReactAndroid')
+    } else {
+        implementation "com.facebook.react:react-native:+"
+    }
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"
     implementation "androidx.appcompat:appcompat:1.1.0"

android/react-native-build.gradle

@@ -0,0 +1,24 @@
+buildscript {
+    repositories {
+        google()
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.6.2'
+        classpath 'de.undercouch:gradle-download-task:4.0.4'
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+    }
+    configurations.all {
+        resolutionStrategy {
+            dependencySubstitution {
+                substitute module("com.facebook.react:react-native:+") with project(":ReactAndroid")
+            }
+        }
+    }
+}

android/test-app-util.gradle

@@ -1,5 +1,10 @@
 import java.nio.file.Paths
 
+ext.buildReactNativeFromSource = { baseDir ->
+    def reactNativePath = findNodeModulesPath(baseDir, 'react-native')
+    return !file("${reactNativePath}/android").exists()
+}
+
 ext.findFile = { fileName ->
     def currentDir = file(rootDir)
     while (currentDir != null) {

example/package.json

@@ -11,7 +11,7 @@
   },
   "peerDependencies": {
     "react": "~16.8.6 || ~16.9.0 || ~16.11.0 || ~16.13.1",
-    "react-native": "^0.60.6 || ^0.61.5 || ^0.62.2 || ^0.63",
+    "react-native": "^0.60.6 || ^0.61.5 || ^0.62.2 || ^0.63 || 1000.0.0",
     "react-native-macos": "^0.60 || ^0.61.39"
   },
   "devDependencies": {

package.json

@@ -41,7 +41,7 @@
   },
   "peerDependencies": {
     "react": "~16.8.6 || ~16.9.0 || ~16.11.0 || ~16.13.1",
-    "react-native": "^0.60.6 || ^0.61.5 || ^0.62.2 || ^0.63",
+    "react-native": "^0.60.6 || ^0.61.5 || ^0.62.2 || ^0.63 || 1000.0.0",
     "react-native-macos": "^0.60 || ^0.61.39"
   },
   "devDependencies": {

test-app.gradle

@@ -1,9 +1,20 @@
 import groovy.json.JsonSlurper
+import java.nio.file.Paths
 import org.gradle.initialization.DefaultSettings
 
 private static void apply(Settings settings) {
     def projectDir = settings.findNodeModulesPath(settings.rootDir, "react-native-test-app")
 
+    if (settings.buildReactNativeFromSource(settings.rootDir)) {
+        def buildFile = Paths.get("${projectDir}/android/react-native-build.gradle")
+        settings.rootProject.buildFileName = settings.rootDir.toPath().relativize(buildFile)
+
+        def reactNativeDir = settings.findNodeModulesPath(settings.rootDir, "react-native")
+        settings.include(":ReactAndroid")
+        settings.project(":ReactAndroid")
+                .projectDir = new File("${reactNativeDir}/ReactAndroid")
+    }
+
     settings.include(":app")
     settings.project(":app")
             .projectDir = new File("${projectDir}/android/app")