Auto-detect Android build-tools version

Use <android build-tools-version="" /> to specify a version in project xml.

lime/project/ProjectXMLParser.hx

@@ -1852,6 +1852,10 @@ class ProjectXMLParser extends HXProject {
 								case "target-sdk-version":
 									
 									config.set ("android.target-sdk-version", Std.parseInt (value));
+
+								case "build-tools-version":
+
+									config.set ("android.build-tools-version", value);
 								
 								case "install-location":
 									

lime/tools/helpers/AndroidHelper.hx

@@ -71,6 +71,61 @@ class AndroidHelper {
 		
 	}
 	
+	public static function getBuildToolsVersion (project:HXProject):String {
+
+		var buildToolsPath = project.environment.get ("ANDROID_SDK") + "/build-tools/";
+
+		var version = ~/^(\d+)\.(\d+)\.(\d+)$/i;
+		var current = { major : 0, minor : 0, micro : 0 };
+
+		for (buildTool in FileSystem.readDirectory (buildToolsPath)) {
+
+			//gradle only likes simple version numbers (x.y.z)
+
+			if (!version.match (buildTool)) {
+
+				continue;
+
+			}
+
+			var newVersion = {
+				major: Std.parseInt (version.matched (1)),
+				minor: Std.parseInt (version.matched (2)),
+				micro: Std.parseInt (version.matched (3))
+			};
+
+			if (newVersion.major != current.major) {
+
+				if (newVersion.major > current.major) {
+
+					current = newVersion;
+
+				}
+
+			} else if (newVersion.minor != current.minor) {
+
+				if (newVersion.minor > current.minor) {
+
+					current = newVersion;
+
+				}
+
+			} else {
+
+				if (newVersion.micro > current.micro) {
+
+					current = newVersion;
+
+				}
+
+			}
+
+		}
+
+		return '${current.major}.${current.minor}.${current.micro}';
+
+	}
+
 	
 	public static function getDeviceSDKVersion (deviceID:String):Int {
 		

lime/tools/platforms/AndroidPlatform.hx

@@ -321,6 +321,7 @@ class AndroidPlatform extends PlatformTarget {
 		context.ANDROID_INSTALL_LOCATION = project.config.getString ("android.install-location", "auto");
 		context.ANDROID_MINIMUM_SDK_VERSION = project.config.getInt ("android.minimum-sdk-version", 9);
 		context.ANDROID_TARGET_SDK_VERSION = project.config.getInt ("android.target-sdk-version", 19);
+		context.ANDROID_BUILD_TOOLS_VERSION = project.config.getString ("android.build-tools-version");
 		context.ANDROID_EXTENSIONS = project.config.getArrayString ("android.extension");
 		context.ANDROID_PERMISSIONS = project.config.getArrayString ("android.permission", [ "android.permission.WAKE_LOCK", "android.permission.INTERNET", "android.permission.VIBRATE", "android.permission.ACCESS_NETWORK_STATE" ]);
 		context.ANDROID_GRADLE_VERSION = project.config.getString ("android.gradle-version", "2.10");
@@ -344,6 +345,12 @@ class AndroidPlatform extends PlatformTarget {
 			Sys.exit (1);
 			
 		}
+
+		if (context.ANDROID_BUILD_TOOLS_VERSION == "") {
+
+			context.ANDROID_BUILD_TOOLS_VERSION = AndroidHelper.getBuildToolsVersion (project);
+
+		}
 		
 		var escaped = ~/([ #!=\\:])/g;
 		context.ANDROID_SDK_ESCAPED = escaped.replace(context.ENV_ANDROID_SDK, "\\$1");

templates/android/template/gradle.properties

@@ -19,7 +19,7 @@ VERSION_CODE=::META_BUILD_NUMBER::
 ANDROID_BUILD_TARGET_SDK_VERSION=::ANDROID_TARGET_SDK_VERSION::
 ANDROID_BUILD_MIN_SDK_VERSION=::ANDROID_MINIMUM_SDK_VERSION::
 ANDROID_BUILD_SDK_VERSION=::ANDROID_TARGET_SDK_VERSION::
-ANDROID_BUILD_TOOLS_VERSION=24.0.1
+ANDROID_BUILD_TOOLS_VERSION=::ANDROID_BUILD_TOOLS_VERSION::
 
 ::if KEY_STORE::
 KEY_STORE=::KEY_STORE::