Android TensorFlow MNIST Machine Learning Example

Forked from MindorksOpenSource/AndroidTensorFlowMNISTExample.

Changed things are:

Some deprecated or outdated function calls were changed.

Some things were removed or simplified.

How to build library files

Current libtensorflow_inference.so and libandroid_tensorflow_inference_java.jar were built with TensorFlow v1.0.1.

If you want to build them with the newer version of TensorFlow,

read this guide or do the following:

Build libtensorflow_inference.so

Clone the TensorFlow's repository and edit WORKSPACE file:

$ cd tensorflow
$ vi WORKSPACE

Edit android_sdk_repository and android_ndk_repository section like this:

# Uncomment and update the paths in these entries to build the Android demo.
android_sdk_repository(
    name = "androidsdk",
    api_level = 23,
    build_tools_version = "25.0.1",
    # Replace with path to Android SDK on your system
    path = "/Users/meinside/Documents/files/dev/android-sdk-macosx",
)

# Android NDK r12b is recommended (higher may cause issues with Bazel)
android_ndk_repository(
    name="androidndk",
    path="/Users/meinside/Downloads/android-ndk-r12b",
    api_level=14) # This needs to be 14 or higher to compile TensorFlow.

Then run:

$ bazel build -c opt //tensorflow/contrib/android:libtensorflow_inference.so \
   --crosstool_top=//external:android/crosstool \
   --host_crosstool_top=@bazel_tools//tools/cpp:toolchain \
   --cpu=armeabi-v7a

If you need .so files for other platforms, replace --cpu=armeabi-v7a with the desired one:

• --cpu=arm64
• --cpu=x86
• --cpu=x86_64
• ...

Compiled file will be placed at bazel-bin/tensorflow/contrib/android/libtensorflow_inference.so.

Copy it into app/src/main/jniLibs/{PLATFORM_NAME}/:

$ mkdir -p {APP_SRC_DIR}/app/src/main/jniLibs/arm64/
$ cp bazel-bin/tensorflow/contrib/android/libtensorflow_inference.so {APP_SRC_DIR}/app/src/main/jniLibs/arm64/

Note: NDK version

At the time of writing, (2017-03-30)

both TensorFlow 1.0.0 and 1.0.1 fails to build libtensorflow_inference.so with latest NDK version(r13).

But I could build it with r12b.

Build libandroid_tensorflow_inference_java.jar

Run:

$ bazel build //tensorflow/contrib/android:android_tensorflow_inference_java

then copy bazel-bin/tensorflow/contrib/android/libandroid_tensorflow_inference_java.jar into app/libs/:

$ cp bazel-bin/tensorflow/contrib/android/libandroid_tensorflow_inference_java.jar {APP_SRC_DIR}/app/libs/

How to train it yourself

Run mnist.py and overwrite generated mnist_model_graph.pb into app/src/main/assets/.

$ cd {APP_SRC_DIR}
$ python mnist.py
$ cp model/mnist_model_graph.pb app/src/main/assets/