[Android] Remove maven dependency of flatbuffers and use source folder (#7503)

.github/workflows/build.yml

@@ -294,7 +294,6 @@ jobs:
       run: echo "::set-output name=hashes::$(shasum -a 256 Mac.flatc.binary.zip | base64)"
 
   build-android:
-   if: false
    name: Build Android (on Linux)
    runs-on: ubuntu-latest
    steps:

android/app/build.gradle

@@ -8,7 +8,7 @@ android {
 
   defaultConfig {
     applicationId "com.flatbuffers.app"
-    minSdkVersion 16
+    minSdkVersion 26
     targetSdkVersion 30
     versionCode 1
     versionName "1.0"
@@ -18,6 +18,14 @@ android {
       targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    sourceSets {
+      main {
+        java {
+          srcDir '../../java'
+        }
+      }
+    }
+
     ndk {
       abiFilters 'arm64-v8a', 'armeabi-v7a'
     }
@@ -105,30 +113,6 @@ android {
       dependsOn(generateFbsCpp)
     }
   }
-
-//  flavorDimensions "stl-variant"
-//  productFlavors {
-//    gnustl {
-//      dimension "stl-variant"
-//      applicationIdSuffix ".gnustl"
-//      versionNameSuffix "-gnustl"
-//      externalNativeBuild {
-//        ndkBuild {
-//          arguments "APP_STL=gnustl_static"
-//        }
-//      }
-//    }
-//    libcpp {
-//      dimension "stl-variant"
-//      applicationIdSuffix ".libcpp"
-//      versionNameSuffix "-libcpp"
-//      externalNativeBuild {
-//        ndkBuild {
-//          arguments "APP_STL=c++_static"
-//        }
-//      }
-//    }
-//  }
 }
 
 dependencies {
@@ -136,6 +120,8 @@ dependencies {
   implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
   implementation 'androidx.core:core-ktx:1.3.2'
   implementation 'androidx.appcompat:appcompat:1.2.0'
-  implementation 'com.google.flatbuffers:flatbuffers-java:2.0.0'
+
+  // If you using java runtime you can add its dependency as the example below
+  // implementation 'com.google.flatbuffers:flatbuffers-java:$latest_version'
 
 }

android/app/src/main/cpp/generated/animal_generated.h

@@ -6,6 +6,13 @@
 
 #include "flatbuffers/flatbuffers.h"
 
+// Ensure the included flatbuffers.h is the same version as when this file was
+// generated, otherwise it may not be compatible.
+static_assert(FLATBUFFERS_VERSION_MAJOR == 2 &&
+              FLATBUFFERS_VERSION_MINOR == 0 &&
+              FLATBUFFERS_VERSION_REVISION == 8,
+             "Non-compatible flatbuffers version included");
+
 namespace com {
 namespace fbs {
 namespace app {

android/app/src/main/java/generated/com/fbs/app/Animal.kt

@@ -36,7 +36,7 @@ class Animal : Table() {
             return if(o != 0) bb.getShort(o + bb_pos).toUShort() else 0u
         }
     companion object {
-        fun validateVersion() = Constants.FLATBUFFERS_2_0_0()
+        fun validateVersion() = Constants.FLATBUFFERS_2_0_8()
         fun getRootAsAnimal(_bb: ByteBuffer): Animal = getRootAsAnimal(_bb, Animal())
         fun getRootAsAnimal(_bb: ByteBuffer, obj: Animal): Animal {
             _bb.order(ByteOrder.LITTLE_ENDIAN)