feat: backwards-compatible AndroidX support Fixes #674, #724, #726

Author: mikehardy

android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.3.2'
+        classpath 'com.android.tools.build:gradle:3.4.2'
     }
 }
 
@@ -40,10 +40,18 @@ repositories {
 }
 
 dependencies {
+    // Use either AndroidX library names or old/support library names based on major version of support lib
+    def supportLibVersion = safeExtGet('supportLibVersion', '28.0.0')
+    def supportLibMajorVersion = supportLibVersion.split('\\.')[0] as int
+    def appCompatLibName =  (supportLibMajorVersion < 20) ? "androidx.appcompat:appcompat" : "com.android.support:appcompat-v7"
+    def supportV4LibName =  (supportLibMajorVersion < 20) ? "androidx.legacy:legacy-support-v4" : "com.android.support:support-v4"
+    def supportV4Version = safeExtGet('supportV4Version', safeExtGet('supportLibVersion', '28.0.0'))
+    def mediaCompatLibName =  (supportLibMajorVersion < 20) ? "androidx.media:media" : "com.android.support:support-media-compat"
+    def mediaCompatVersion = safeExtGet('mediaCompatVersion', safeExtGet('supportLibVersion', '28.0.0'))
+
     implementation "com.facebook.react:react-native:${safeExtGet('reactNativeVersion', '+')}"
     implementation "com.google.android.gms:play-services-gcm:${safeExtGet('googlePlayServicesVersion', '16.1.0')}"
-    //noinspection GradleCompatible
-    implementation "com.android.support:appcompat-v7:${safeExtGet('supportLibVersion', '28.0.0')}"
-    implementation "com.android.support:support-v4:${safeExtGet('supportLibVersion', '28.0.0')}"
-    implementation "com.android.support:support-media-compat:${safeExtGet('supportLibVersion', '28.0.0')}"
+    implementation "$appCompatLibName:$supportLibVersion"
+    implementation "$supportV4LibName:$supportV4Version"
+    implementation "$mediaCompatLibName:$mediaCompatVersion"
 }