If you have worked through Compiling orx and the Android demo and all compiled and deployed fine, then you are right to continue with this tutorial.

That means your own application should be able to work under Android. There are pitfalls along the way and I'll do my best to guide you through. You don't have to know Java or Android to make use of this guide.

Depending how you structure your own project, (especially if you use the init script to create your projects) it is likely that you have a folder layout something like this:

  bin
  build
      windows
          codelite
      mac
          xcode
  data
  include
  lib
  src

Perhaps you are targeting more than one operating system and IDE. You'll want to add the Android demo project to the build folder where it can be customised to work with your project. So copy the whole orx/code/demo/android folder to your build folder so it becomes:

  bin
  build
      android <------- here
          app/
          gradle/
          build.bat
          build.gradle
          build.sh
          gradle.properties
          gradlew
          gradlew.bat
          settings.gradle
      windows
      mac
  data
  include
  lib
  src

The Application ID notation is used to make Android applications (and their ownership) unique from all other applications that are available.

This notation is peppered through many files in the demo project and we'll need to change all of them to make the project your own. The notation used in the demo is:

 org.orxproject.orxtest.OrxDemo

• The org.orxproject.orxtest portion is called the Package Name and also the Application ID.
• The OrxDemo portion is the Class Name.
• The entire sequence which is org.orxproject.orxtest.OrxDemo is the Activity.

To make this demo easier to follow, let's come up with a fantasy application name and company.

Imagine you owned the domain name: rabbitgames.net And your game was Rocket Boy. Then a good identifier might be:

 net.rabbitgames.rocketboy.RocketBoyGame

So therefore:

• net.rabbitgames.rocketboy would be your Package Name and Application ID.
• RocketBoyGame would be the Class Name.
• net.rabbitgames.rocketboy.RocketBoyGame would be the Activity.

These names do not represent anything visual in your game itself, title, or icon, etc. Those are defined elsewhere.

We will apply this notation though the files coming up.

Read more about this at: https://developer.android.com/studio/build/application-id

If you don't know what an APK is, it is like an installer package for Android, similar to a setup.exe for Windows.

The string you choose will become the name of the APK, for example: app-debug.apk and app-debug-unaligned.apk

Similar to the naming we discussed earlier, let's call the app: rocket-boy.

Edit the build/android/settings.gradle file and change from:

 include ':app'

to:

 include ':rocket-boy'

This is also known as the project name.

Also:

rootProject.name = "Orx Demo"

to:

rootProject.name = "Rocket Boy"

Now you need to rename the folder build/android/app folder to match. So it becomes: build/android/rocket-boy.

Edit the meta data in the build/android/rocket-boy/src/main/AndroidManifest.xml file:

from:

<meta-data android:name="android.app.lib_name" android:value="orxDemo" />

to:

<meta-data android:name=“android.app.lib_name” android:value=“RocketBoyGame” />

Edit the following at build/android/rocket-boy/build.gradle.

namespace 'org.orx.demo'

to:

namespace 'net.rabbitgames.rocketboy'

And:

applicationId "org.orx.demo"
  

to:

applicationId "net.rabbitgames.rocketboy"

Change all manifestPlaceholders from:

manifestPlaceholders = [ gameArguments: 'orxDemo' ]
manifestPlaceholders = [ gameArguments: 'orxDemoDebug' ]
manifestPlaceholders = [ gameArguments: 'orxDemoProfile' ]

to become:

manifestPlaceholders = [ gameArguments: 'RocketBoyGame' ]
manifestPlaceholders = [ gameArguments: 'RocketBoyGameDebug' ]
manifestPlaceholders = [ gameArguments: 'RocketBoyGameProfile' ]

To read more about the importance of your application id: https://developer.android.com/studio/build/application-id and http://developer.android.com/guide/topics/manifest/manifest-element.html#package

This is how to set the title text for your application icon when loaded on your device.

The App name is located at: build/android/rocket-boy/src/main/res/values/strings.xml

  <string name="app_name">OrxDemo</string>

Change to:

  <string name="app_name">Rocket Boy</string>

Your application must also be given a module name. You set this name in three places. The module name must match:

build/android/rocket-boy/src/main/jni/Android.mk

LOCAL_MODULE    := RocketBoyGame

Next file to change is: build/android/rocket-boy/src/main/jni/Application.mk

APP_MODULES = RocketBoyGame

All your source files, *.cpp and *.h can be copied into the build/android/rocket-boy/src/main/jni folder. However if your prefer, you can source them from your existing project with a relative path.

To ensure your C/C++ files are compiled, each source file (but not header files) will need to be listed in the build/android/rocket-boy/src/main/jni/Android.mk. If you copied your source files to the assets folder, you can just specify the files like this:

 LOCAL_SRC_FILES := file01.cpp file02.cpp file03.cpp file04.cpp file05.cpp
 

Or to access them relatively:

LOCAL_SRC_FILES := ../../../../../../src/file01.cpp ../../../../../../src/file02.cpp

Note that if you followed the same file structure in this tutorial, the six parent levels to get to your source files would be correct.

You can delete the unused orxDemo.cpp on disk.

The files need to be laid out on the same line due to CR/LF issues in the file, causing errors like

 "*** commands commence before first target. Stop.". 

Listing on one line makes the problem go away.

Orx will load its startup ini file from the build/android/rocket-boy/src/main/assets folder.

Because of the manifestPlaceholders configured earlier, Orx will try to load RocketBoyGameDebug.ini when in debug mode, or RocketBoyGame.ini for release mode. (Debug or release APKs are covered later).

From these initial ini files, you can load your other project application files. But please note that your Android application will not be able reach back into a parent path for assets. These all need to live in your build/android/rocket-boy/src/main/assets folder. Therefore it will be useful for you to consider creating a publishing script to regularly copy all your Orx assets from the project into this assets folder.

?? Not sure which mode you are compiling for? Have a look in the build/android/rocket-boy/src/main/jni/Android.mk file. The “LOCAL_STATIC_LIBRARIES := orxd” line tells it is orxd (debug). In this case, load orxd.ini. ??

To learn more about bootstrapping different ini files at: changing the default ini file here.

All your PNGs and OGGs and whatever else need to be copied into the build/android/rocket-boy/src/main/assets folder, just like the INI files.

Consider a publishing script to periodically copy them from your project data folder to Android assets folder.

Open a terminal and go to:

build/android

And type:

build.bat (for Windows or)
build.sh (Linux / Mac)

Locate your APK files in: build\android\rocket-boy\build\outputs\apk\debug

You are done!

There are three ways to test your application:

1. Using Android Studio Connecting a phone via USB in Developer Mode. Select Run > Run 'RocketBoyGame' to send to the phone. You can track application progress and logs via Android Studio's output pane.
2. Using the “Debug or Profile APK” in Android Studio, select Run > Run 'RocketBoyGame' to send to the Android Emulator. This also has good logging.
3. Take the APK and manually copy it to your device.

Before you can generate a release APK, you will need to sign it. You don't need to do this for debug APKs. You can do this by:

  1. Right clicking on the "rocket-boy" project.
  2. Click "Open Module Settings"
  3. Click the "Signing" tab.
  4. Click the + sign.

Continue on, by visiting the following link: http://developer.android.com/tools/publishing/app-signing.html and scroll down to the section titled “Signing Your App in Android Studio”.

• General compile issues or failing APK on a phone. First thing to track down is mismatches in the naming of the project folders, and application ids, classname, etc. Go back and check each one for typos or mismatches.
• You need to ensure that paths are correct to your images and sounds. Your config between Android and other platforms will be different. You can use the [Resource] config option to configure multiple paths to reach ini files and assets.
• If you are sick of manually copying your image and sound assets, and concatenating ini files, some scripts will be published here soon that you can use in your own projects.