SFML for ANDROID

You'll find here the detailled steps to build SFML and use it in an Android Studio project.

Build SFML

get the basics

• Get JDK here and install.
• Get Android Studio here, Install and Run. The SDK will be placed in $HOME/Library/Android/sdk/
• Start and Add more packages (LLDB, NDK, CMake, ...) see https://developer.android.com/ndk/guides/index.html
• note: all this will take a lot of space, be ready for it.
• AndroidStudio will create $HOME/StudioProjects
• get Android NDK-r12b here(we'll need it for SFML, thanks to Alia5 for the tip!
• unpack it in $HOME/Library/Android rename the folder ndk_r12b
• if you need CMake get it here. Then add it to the PATH in your .profile using nano or vi. PATH=$PATH:/Applications/CMake.app/Contents/bin, finally source $HOME/.profile

Let's proceed to building SFML

• open Terminal, cd $HOME/StudioProjects/
• get SFML git clone https://github.com/SFML/SFML.git
• as a result you get: $HOME/StudioProjects/SFML/...
• set a SFML variable: SFML=$HOME/StudioProjects/SFML
• go to the SFML folder cd $SFML and create a build folder mkdir build, then cd build

create the x86 libs

• create an architecture folder mkdir x86 (to use the emulator) and go there cd x86
• create the makefile using cmake cmake -DANDROID_ABI=x86 -DCMAKE_TOOLCHAIN_FILE=$SFML/cmake/toolchains/android.toolchain.cmake -DANDROID_NDK=$HOME/Library/Android/ndk_r12b -DCMAKE_FIND_FRAMEWORK="NEVER" -DANDROID_STL=c++_shared -DCMAKE_BUILD_TYPE=Debug $SFML
• build SFML libs for architecture x86 make

create the armeabiXXXX libs

repeat what you did for the x86 libs for armeabi and armeabi-v7a architectures

cd $SFML/build
mkdir armeabi
cd armeabi	

cmake -DANDROID_ABI=armeabi -DCMAKE_TOOLCHAIN_FILE=$SFML/cmake/toolchains/android.toolchain.cmake -DANDROID_NDK=$HOME/Library/Android/ndk_r12b -DCMAKE_FIND_FRAMEWORK="NEVER" -DANDROID_STL=c++_shared $SFML
make

and finally

cd $SFML/build
mkdir armeabi-v7a
cd armeabi-v7a	

cmake -DANDROID_ABI=armeabi-v7a -DCMAKE_TOOLCHAIN_FILE=$SFML/cmake/toolchains/android.toolchain.cmake -DANDROID_NDK=$HOME/Library/Android/ndk_r12b -DCMAKE_FIND_FRAMEWORK="NEVER" -DANDROID_STL=c++_shared $SFML
make

when this is done, put all the libs created somewhere you can find them

mkdir $SFML/lib
cp $SFML/build/x86/* $SFML/lib/x86
cp $SFML/build/armeabi/* $SFML/lib/armeabi
cp $SFML/build/armeabi-v7a/* $SFML/lib/armeabi-v7a

also add the extlibsthat aren't statically linked to the SFML libs (the .so).

cp $SFML/extlibs/libs-android/x86/*.so $SFML/lib/x86
cp $SFML/extlibs/libs-android/armeabi/*.so $SFML/lib/armeabi
cp $SFML/extlibs/libs-android/armeabi-v7a/*.so $SFML/lib/armeabi-v7a

you're ready for the second part... build an App.

Build your SFML App

If you want to use the Template you can skip this. I would advise you to try it the long way first (it's good practice).

So, from scratch: Start Android Studio and create a new project by importing a sample. The one you want is NDK/NativeActivity. Name your project and ... wait. You might be requested to update settings to use a newer version of Gradle: do so.

we'll have to change 3 files to make it work:

• AndroidManifest.xml
• build.gradle (module: app)
• CMakeLists.txt

AndroidManifest.xml

you'll find it in Project/app/manifests/. Change your App Bundle name in <manifest package="my.app.bundle"> to whatever you'd like it to be.

Now the really important bit is in the <application> tag. You want to tell NativeActivity to use the sfml-activity. To do so, change android:value="native-activity" to android:value="sfml-activity".

Then you want to tell SFMLActivity where to find int main(int argc, char *argv[]). to do so add a new <meta-data> tag after the previous one like this:

<!-- Tell NativeActivity the name of our activity.so (sfml-activity)-->
<meta-data android:name="android.app.lib_name"
  android:value="sfml-activity" /><!-- Never change this! -->
<!-- Tell sfml-activity (see SFML_Activity.cpp) the name of our app.so -->
<meta-data android:name="sfml.app.lib_name"
  android:value="my-app" /><!-- match it to CMakeLists.txt -->

done.

here's a complete example for your reference:

<?xml version="1.0" encoding="utf-8"?>
<!-- BEGIN_INCLUDE(manifest) -->
<!-- change myappname in Gradle:app too -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="sfml.example.myappname"
          android:versionCode="1"
          android:versionName="1.0">

  <!-- This .apk has no Java code itself, so set hasCode to false. -->
  <application
      android:allowBackup="false"
      android:fullBackupContent="false"
      android:icon="@mipmap/ic_launcher"
      android:label="SFML TEST"
      android:hasCode="false">

    <!-- Our activity is the built-in NativeActivity framework class.
         This will take care of integrating with our NDK code. -->
    <activity android:name="android.app.NativeActivity"
              android:label="@string/app_name"
              android:configChanges="orientation|keyboardHidden">
      <!-- Tell NativeActivity the name of our activity.so (sfml-activity)-->
      <meta-data android:name="android.app.lib_name"
          android:value="sfml-activity" /><!-- Never change this! -->
      <!-- Tell sfml-activity (see SFML_Activity.cpp) the name of our app.so -->
      <meta-data android:name="sfml.app.lib_name"
          android:value="my-app" /><!-- match it to CMakeLists.txt -->

      <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
    </activity>
  </application>

</manifest>
<!-- END_INCLUDE(manifest) --> 

build.gradle (Module: app)

Before doing anything here, copy the sfml libs inside your project.

or even better, create som symbolic links to the libs in $SFML

cd $YOUR_PROJECT
mkdir sfml
ln -s $SFML/lib sfml/lib
ln -s $SFML/include sfml/include 

Your project folder should look like this:

StudioProjects/MyProject/
	app/
	build/
	gradle/
	sfml/
		include/	# this is a link
			FLAC/stuff.h
			...
			SFML/
			...
			Vorbis/
		lib/ # this is a link
			armeabi/stuff.so
			armeabi-v7a/
			x86/
			mips/

you must now change the App Bundle name in defaultConfig { applicationId = '...' } to the same value you've defined earlier in the AndroidManisfest.xml file.

Next, let's specify the STL used and the cppFlags

defaultConfig {
  ...
  externalNativeBuild {
    cmake {
        cppFlags "-std=c++11 -fexceptions -frtti"
        arguments '-DANDROID_STL=c++_shared'
    }
  }
}

Now to tell gradle to copy our libs where they can be found by the App, add this block right after externalNativeBuild { cmake { path 'src/main/cpp/CMakeLists.txt' } }

// If you want Gradle to package prebuilt native libraries
// with your APK (you do!), modify the default source set configuration
// to include the directory of your prebuilt .so files as follows.
// note: put the sfml libs in MyProject/sfml/lib/(architecture)/libsfml(...).so
sourceSets {
    main {
        jniLibs.srcDirs = ['../sfml/lib/']
    }
} 

done.

CmakeLists.txt

What you want to do here is to specify where the libs are and what to build depending on the architecture required. So here goes

cmake_minimum_required(VERSION 3.4.1)
	
set(sfml_dir ${CMAKE_SOURCE_DIR}/../../../../sfml)
set(sfml_lib ${sfml_dir}/lib/${ANDROID_ABI})
set(sfml_include ${sfml_dir}/include)

# path to include.hpp files
include_directories(
    ${sfml_include}
    )

shared lib will also be tucked into APK and sent to target (refer to app/build.gradle, jniLibs section for that purpose). We use ${ANDROID_ABI} hereto determine on the fly which architecture to link to (useful if like me you don't have an android device and want to use the simulator)

Next we define where all our libs are:

#--- ADD LIBS: prebuilt libraries (3rd party)
add_library(sfml-main STATIC IMPORTED)
set_target_properties(sfml-main PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-main.a)

add_library(sfml-activity SHARED IMPORTED)
set_target_properties(sfml-activity PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-activity.so)

add_library(sfml-system SHARED IMPORTED)
set_target_properties(sfml-system PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-system.so)

add_library(sfml-window SHARED IMPORTED)
set_target_properties(sfml-window PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-window.so)

add_library(sfml-graphics SHARED IMPORTED)
set_target_properties(sfml-graphics PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-graphics.so)

add_library(sfml-audio SHARED IMPORTED)
set_target_properties(sfml-audio PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libsfml-audio.so)

add_library(openal SHARED IMPORTED)
set_target_properties(openal PROPERTIES IMPORTED_LOCATION ${sfml_lib}/libopenal.so)

finally we can build our final app lib and link all the libs together!

# --- ADD LIBS: build main app lib
# Export ANativeActivity_onCreate(),
# Refer to: https://github.com/android-ndk/ndk/issues/381.
set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -u ANativeActivity_onCreate")

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds it for you.
# Gradle automatically packages shared libraries with your APK.
# build native_app_glue as a static lib
# Provides a relative path to your source file(s).
# Associated headers in the same location as their source
# file are automatically included.
add_library(my-app SHARED 
	main.cpp
	)

# --- TARGET
target_include_directories(my-app PRIVATE
                           ${sfml_include}
                           )

target_link_libraries(my-app # specifies the target lib
    # link the target libs

    #custom_native_app_glue
    # sfml-main

    android
    log

    EGL
    GLESv1_CM

    openal
    sfml-audio

    sfml-system
    sfml-window
    sfml-graphics
    sfml-activity
    
	# neat one, thanks Alia5
    -Wl,--whole-archive sfml-main -Wl,--no-whole-archive
    )

now you can use SFML in your main.cpp file.

sync, build, run, pray and enjoy.

Lio

Visit http://movo-design.com to see my game TacWars on OSX,IOS and very soon Android.