The tutorial assumes that the Android SDK and Android NDK are already installed correctly. The SFML_GRAPHICS backend was tested up to NDK r18b, as SFML 2.5.1 (latest version at time of writing) didn’t work out of the box with newer NDK versions (it failed to find the GLES library).
You will need to use CMake in order to build TGUI. You can download the latest version here.
The TGUI source code can be downloaded from the download page.
SFML should have already been installed inside the NDK before building TGUI.
Create a new folder inside the downloaded TGUI folder (e.g. called “build-android-armeabi-v7a”). Open a terminal inside this folder and run the following command (with optionally a few changes as explained below).
cmake -DCMAKE_SYSTEM_NAME=Android -DCMAKE_ANDROID_NDK=/path/to/ndk -DCMAKE_ANDROID_ARCH_ABI=armeabi-v7a -DCMAKE_BUILD_TYPE=Debug ..
CMAKE_ANDROID_NDK has to be the path to the NDK (which will end in something like “ndk/18.1.5063045” if you installed the NDK using the sdkmanager).
CMAKE_ANDROID_ARCH_ABI specifies the architecture to use. To use TGUI on real hardware you will need arm64-v8a (or armeabi-v7a if you still want to support 32-bit devices). To run TGUI on a simulator you will likely need x86 (32-bit) or x86_64 (64-bit), depending on which simulator you installed. The architecture has to match the SFML libraries, so you may be limited to x86 and armeabi-v7a as SFML 2.5.1 doesn’t contain 64-bit extlibs and thus doesn’t support arm64-v8a or x86_64 out of the box.
CMAKE_BUILD_TYPE chooses whether you want to build a Release or Debug library. The example code currently requires Debug libraries (due to hardcoded values).
On Windows you might also have to pass your generator to the cmake command with the -G parameter. On Linux and macOS, “Unix Makefiles” will be used by default.
Depending on the generator, CMake will have created a build file or project. For “Unix Makefiles” you use the following commands in the terminal to build the library and install it to the NDK folder. The “-j2” after the make command means it uses 2 threads, if you have more cores you can increase the number to speed up the build.
make -j2
make install
To test if everything is working, you can build the example code.
If the ANDROID_SDK_ROOT environment variable isn’t set then open the TGUI/examples/android folder add a “local.properties” file with the following contents, specifying the android SDK paths:
sdk.dir=/path/to/android-sdk
Verify that the ndkVersion in app/build.gradle inside the android example folder matches the NDK version that you are using. In the same file, also check that abiFilters matches the CMAKE_ANDROID_ARCH_ABI that was passed to cmake. The error that TGUI.hpp is not found can mean that the abiFilters value is wrong.
Now you should be able to build project with gradle by running the following from the command line in the TGUI/examples/android directory:
./gradlew buildDebug
If this results in an error stating Could not open terminal for stdout: could not get termcap entry then set the TERM variable to dumb (e.g. run TERM=dumb ./gradlew buildDebug on Linux).
If all goes well then you can now install the apk to a device (or a running simulator) by running
./gradlew installDebug
In the Android.mk file you must add the tgui library
LOCAL_SHARED_LIBRARIES += tgui
You also have to import TGUI in that file. Importing SFML is not needed as TGUI will already do that for you.
$(call import-module, third_party/tgui)
In Application.mk you must enable exceptions and RTTI, add the tgui-activity module and make sure you use c++14 or higher.
APP_CPPFLAGS += -fexceptions -frtti -std=c++14
APP_MODULES := sfml-activity tgui-activity your-program
Finally you have to load the tgui-activity so that it can load the tgui library. You do that by having the following in your AndroidManifest.xml file (inside the activity element). The order is important, you must load SFML before TGUI. The your-program name should match the LOCAL_MODULE value in Android.mk.
<meta-data android:name="android.app.lib_name" android:value="sfml-activity" />
<meta-data android:name="sfml.app.lib_name" android:value="tgui-activity" />
<meta-data android:name="tgui.app.lib_name" android:value="your-program" />
That’s it. You should now know enough to use tgui in your project.