Support for Unity 2019 Android SDK and JDK install locations

Unity 2019 adds support for installation of the Android SDK and JDK in
the AndroidPlayer directory making it easier for developers to configure
the Android build environment.  Unfortunately, Unity does not update
the JdkPath and AndroidSdkRoot editor preferences when the Android SDK
and JDK are installed with the AndroidPlayer.

This change searches for the Android SDK and JDK if JdkPath and
AndroidSdkRoot are not set.

Fixes #188

Bug: 132072681
Change-Id: If01f642ff81570d9c28552fab6957bc88cf4dac1

Author: Stewart Miles

source/PlayServicesResolver/src/JavaUtilities.cs

@@ -48,20 +48,26 @@ public ToolNotFoundException(string message) : base(message) {}
         /// </summary>
         private static Version MinimumJdkVersion = new Version("1.8");
 
-        /// <summary>
-        /// Get the JDK path (JAVA_HOME) configured in the Unity editor.
-        /// </summary>
-        private static string EditorJavaHome {
-            get { return UnityEditor.EditorPrefs.GetString("JdkPath"); }
-        }
-
         /// <summary>
         /// Find the JDK path (JAVA_HOME) either configured in the Unity editor or via the JAVA_HOME
         /// environment variable.
         /// </summary>
         private static string JavaHome {
             get {
-                var javaHome = EditorJavaHome;
+                var javaHome = UnityEditor.EditorPrefs.GetString("JdkPath");
+                // Unity 2019.x added installation of the JDK in the AndroidPlayer directory
+                // so fallback to searching for it there.
+                if (String.IsNullOrEmpty(javaHome) || EditorPrefs.GetBool("JdkUseEmbedded")) {
+                    var androidPlayerDir = PlayServicesResolver.AndroidPlaybackEngineDirectory;
+                    if (!String.IsNullOrEmpty(androidPlayerDir)) {
+                        var platformDir = UnityEngine.Application.platform.ToString().Replace(
+                            "Editor", "").Replace("OSX", "MacOS");
+                        var openJdkDir = Path.Combine(Path.Combine(Path.Combine(
+                            androidPlayerDir, "Tools"), "OpenJDK"), platformDir);
+                        if (Directory.Exists(openJdkDir)) javaHome = openJdkDir;
+                    }
+                }
+                // If the JDK stil isn't found, check the environment.
                 if (String.IsNullOrEmpty(javaHome)) {
                     javaHome = Environment.GetEnvironmentVariable(JAVA_HOME);
                 }

source/PlayServicesResolver/src/PlayServicesResolver.cs

@@ -608,7 +608,19 @@ public class AndroidAbisChangedArgs : EventArgs {
         /// Get the Android SDK directory.
         /// </summary>
         public static string AndroidSdkRoot {
-            get { return EditorPrefs.GetString("AndroidSdkRoot"); }
+            get {
+                var sdkPath = EditorPrefs.GetString("AndroidSdkRoot");
+                // Unity 2019.x added installation of the Android SDK in the AndroidPlayer directory
+                // so fallback to searching for it there.
+                if (String.IsNullOrEmpty(sdkPath) || EditorPrefs.GetBool("SdkUseEmbedded")) {
+                    var androidPlayerDir = AndroidPlaybackEngineDirectory;
+                    if (!String.IsNullOrEmpty(androidPlayerDir)) {
+                        var androidPlayerSdkDir = Path.Combine(androidPlayerDir, "SDK");
+                        if (Directory.Exists(androidPlayerSdkDir)) sdkPath = androidPlayerSdkDir;
+                    }
+                }
+                return sdkPath;
+            }
         }
 
         /// <summary>
@@ -637,6 +649,22 @@ public class AndroidSdkRootChangedArgs : EventArgs {
         /// </summary>
         public static event EventHandler<AndroidSdkRootChangedArgs> AndroidSdkRootChanged;
 
+        /// <summary>
+        /// Get the Android playback engine directory.
+        /// </summary>
+        /// <returns>Get the playback engine directory.</returns>
+        public static string AndroidPlaybackEngineDirectory {
+            get {
+                try {
+                    return (string)VersionHandler.InvokeStaticMethod(
+                        typeof(BuildPipeline), "GetPlaybackEngineDirectory",
+                        new object[] { BuildTarget.Android, BuildOptions.None });
+                } catch (Exception) {
+                    return null;
+                }
+            }
+        }
+
         /// <summary>
         /// Initializes the <see cref="GooglePlayServices.PlayServicesResolver"/> class.
         /// </summary>

source/VersionHandler/src/VersionHandler.cs

@@ -494,7 +494,15 @@ public static object InvokeStaticMethod(
     public static object InvokeMethod(
             Type type, object objectInstance, string methodName,
             object[] args, Dictionary<string, object> namedArgs = null) {
-        MethodInfo method = type.GetMethod(methodName);
+        Type[] argTypes = null;
+        if (args != null && args.Length > 0) {
+            argTypes = new Type[args.Length];
+            for (int i = 0; i < args.Length; ++i) {
+                argTypes[i] = args[i].GetType();
+            }
+        }
+        MethodInfo method = argTypes != null ?
+            type.GetMethod(methodName, argTypes) : type.GetMethod(methodName);
         ParameterInfo[] parameters = method.GetParameters();
         int numParameters = parameters.Length;
         object[] parameterValues = new object[numParameters];