automatically creates android.mk file for cocos2dx project with all `classes` in classes dir. Run it in proj.android/jni director. Tested for cocos2dx versions 2.x.x

androidmk.java

import java.io.File;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;

public class androidmk {

	/**
	 * @param args
	 */
	
	String before = "LOCAL_PATH := $(call my-dir) \n\ninclude $(CLEAR_VARS) \n\nLOCAL_MODULE := cocos2dcpp_shared" +
			"\n\nLOCAL_MODULE_FILENAME := libcocos2dcpp\n\n";
	
	String classes = "LOCAL_SRC_FILES := hellocpp/main.cpp \\\n";
	
	String after = "\n\n\nLOCAL_C_INCLUDES := $(LOCAL_PATH)/../../Classes\n\n"+
			"LOCAL_WHOLE_STATIC_LIBRARIES += cocos2dx_static\n"+
			"LOCAL_WHOLE_STATIC_LIBRARIES += cocosdenshion_static\n"+
			"LOCAL_WHOLE_STATIC_LIBRARIES += box2d_static\n"+
			"LOCAL_WHOLE_STATIC_LIBRARIES += chipmunk_static\n"+
			"LOCAL_WHOLE_STATIC_LIBRARIES += cocos_extension_static\n\n"+
			"include $(BUILD_SHARED_LIBRARY)\n\n"+
			"$(call import-module,cocos2dx)\n"+
			"$(call import-module,cocos2dx/platform/third_party/android/prebuilt/libcurl)\n"+
			"$(call import-module,CocosDenshion/android)\n"+
			"$(call import-module,extensions)\n"+
			"$(call import-module,external/Box2D)\n"+
			"$(call import-module,external/chipmunk)\n";
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		
		
		// rename the Android.mk file to Android_BAK.mk
		
		File oldfile =new File(System.getProperty("user.dir")+"/Android.mk");
		File newfile =new File(System.getProperty("user.dir")+"/Android_BAK.mk");
	
		try{
			
			if(oldfile.renameTo(newfile)){
				System.out.println("Rename succesful");
			}else{
				System.out.println("Rename failed");
			}
			
		}catch (Exception et) {
			et.printStackTrace();
		}
		
		
		System.out.println("Current dir : "+System.getProperty("user.dir"));
		
		androidmk runner = new androidmk();
		
		String path;

		Path currentRelativePath = Paths.get(System.getProperty("user.dir"));
		currentRelativePath = currentRelativePath.getParent().getParent();
		String s = currentRelativePath.toAbsolutePath().toString();
		

		path = s +"\\Classes";
		System.out.println("Path to Classes : " + path);

		// making new Android.mk file
		
		String classConcat = runner.readFilesFromDir(path,runner.classes);
		
		
		
		try {
			 
			String content = "";
			
			content = runner.before + classConcat + runner.after;
 
			File file = new File(System.getProperty("user.dir")+"/Android.mk");
 
			// if file doesnt exists, then create it
			if (!file.exists()) {
				file.createNewFile();
			}
 
			FileWriter fw = new FileWriter(file.getAbsoluteFile());
			BufferedWriter bw = new BufferedWriter(fw);
			bw.write(content);
			bw.close();
 
			System.out.println("Done");
 
		} catch (IOException e) {
			e.printStackTrace();
		}

	}
	
	
	
	public String readFilesFromDir(String path, String classesStart){
		
		File folder = new File(path);
		File[] listOfFiles = folder.listFiles();
		
		String returnStr="";
	
		    for (int i = 0; i < listOfFiles.length; i++) {
		      if (listOfFiles[i].isFile()) {
		    	  
		    	String fileName = listOfFiles[i].getName();
		    	
		    	if (fileName.split("\\.")[1].equals("cpp")){
		    		
		    		System.out.println("File " + listOfFiles[i].getName());
		    		
		    		returnStr += "\t\t\t../../Classes/" + listOfFiles[i].getName() + " \\\n";
		    		
		    	}  
		    	  
		        
		      } else if (listOfFiles[i].isDirectory()) {
		        System.out.println("Directory " + listOfFiles[i].getName());
		      }
		    }
		    return classesStart + returnStr;
	}

}