Add variables for build tools versions

Author: yongce

AndroidTestingBlueprint/app/build.gradle

@@ -1,8 +1,8 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 22
-    buildToolsVersion '23.0.0rc3'
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     /*
     Test only modules require other artifacts like the classes.jar to be published, so the test can
@@ -12,9 +12,10 @@ android {
     publishNonDefault true
 
     defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+
         applicationId 'com.example.android.testing.blueprint'
-        minSdkVersion 10
-        targetSdkVersion 22
         versionCode 1
         versionName '1.0'
 

AndroidTestingBlueprint/build.gradle

@@ -17,3 +17,10 @@ allprojects {
         jcenter()
     }
 }
+
+ext {
+    minSdkVersion = 10
+    targetSdkVersion = 22
+    compileSdkVersion = 23
+    buildToolsVersion = "23.0.0"
+}

AndroidTestingBlueprint/module-android-library/build.gradle

@@ -1,12 +1,13 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 22
-    buildToolsVersion "23.0.0rc3"
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 10
-        targetSdkVersion 22
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+
         versionCode 1
         versionName "1.0"
 

AndroidTestingBlueprint/module-flavor1-androidTest-only/build.gradle

@@ -1,12 +1,13 @@
 apply plugin: 'com.android.test' // A plugin used for test-only-modules
 
 android {
-    compileSdkVersion 22
-    buildToolsVersion = '23.0.0rc3'
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 10
-        targetSdkVersion 22
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+
         // The package name of the test app
         testApplicationId 'com.example.android.testing.blueprint.test'
         // The Instrumentation test runner used to run tests.