[Android/Api] add readme to build api

add readme to build android library using the script.

Signed-off-by: Jaeyun Jung <jy1210.jung@samsung.com>

diff --git a/README.md b/README.md
index 229355d..dfdfc64 100644 (file)
--- a/README.md
+++ b/README.md
@@ -66,8 +66,9 @@ In [Component Description](Documentation/component-description.md) page, we desc
 
 ## Getting Started
 For more details, please access the following manuals.
-* For Linux-like systems such as Tizen, Debian, and Ubuntu, press [here](Documentation/getting-started.md)
-* For macOS systems, press [here](Documentation/getting-started-macos.md)
+* For Linux-like systems such as Tizen, Debian, and Ubuntu, press [here](Documentation/getting-started.md).
+* For macOS systems, press [here](Documentation/getting-started-macos.md).
+* To build an API library for Android, press [here](api/android/README.md).
 
 ## Usage Examples
 - [Example apps](https://github.com/nnsuite/nnstreamer-example) (stable)

diff --git a/api/android/README.md b/api/android/README.md
new file mode 100644 (file)
index 0000000..34cf756
--- /dev/null
+++ b/api/android/README.md
@@ -0,0 +1,149 @@
+# NNStreamer API Library for Android
+
+## Prerequisite
+
+We assume that you already have experienced Android application developments with Android Studio.
+
+ * Host PC:
+   * OS: Ubuntu 16.04 x86_64 LTS
+   * Android Studio: Ubuntu version
+   * Android SDK: Min version 24 (Nougat)
+   * Android NDK: Use default ndk-bundle in Android Studio
+   * GStreamer: gstreamer-1.0-android-universal-1.16.0
+
+## Build library
+
+#### Environment variables
+
+First of all, you need to set-up the development environment as following:
+
+```bash
+$ mkdir -p $HOME/android/tools/sdk
+$ mkdir -p $HOME/android/gstreamer-1.0
+$ mkdir -p $HOME/android/workspace
+$
+$ vi ~/.bashrc
+# Environmet variables for developing a NNStreamer application
+# $ANDROID_DEV_ROOT/gstreamer-1.0                # GStreamer binaries
+# $ANDROID_DEV_ROOT/tools/sdk                    # Android SDK root directory (default location: $HOME/Android/Sdk)
+# $ANDROID_DEV_ROOT/workspace/nnstreamer         # nnstreamer cloned git repository
+#
+export JAVA_HOME=/opt/android-studio/jre            # JRE path in Android Studio
+export ANDROID_DEV_ROOT=$HOME/android               # Set your own path (The default path will be "$HOME/Android".)
+export ANDROID_SDK=$ANDROID_DEV_ROOT/tools/sdk      # Android SDK (The default path will be "$HOME/Android/Sdk".)
+export ANDROID_HOME=$ANDROID_SDK
+export GSTREAMER_ROOT_ANDROID=$ANDROID_DEV_ROOT/gstreamer-1.0
+export NNSTREAMER_ROOT=$ANDROID_DEV_ROOT/workspace/nnstreamer
+```
+
+#### Download Android Studio
+
+Download and install Android Studio to compile an Android source code.
+You can see the installation guide [here](https://developer.android.com/studio/install).
+
+For example,
+```bash
+$ firefox  https://developer.android.com/studio
+Then, download "Android Studio" in the /opt folder.
+$ cd /opt
+$ wget https://dl.google.com/dl/android/studio/ide-zips/3.4.0.18/android-studio-ide-183.5452501-linux.tar.gz
+$ tar xvzf ./android-studio-ide-183.5452501-linux.tar.gz
+```
+
+#### Download NDK
+
+Use the default NDK in Android Studio.
+
+If you need to set a specific version, download and decompress it to compile normally a GStreamer-based plugin (e.g., NNStreamer).
+You can download older version from [here](https://developer.android.com/ndk/downloads/older_releases.html).
+
+#### Download GStreamer binaries
+
+You can get the prebuilt GStreamer binaries from [here](https://gstreamer.freedesktop.org/data/pkg/android/).
+
+For example,
+```bash
+$ cd $ANDROID_DEV_ROOT/
+$ wget https://gstreamer.freedesktop.org/data/pkg/android/1.16.0/gstreamer-1.0-android-universal-1.16.0.tar.xz
+$ mkdir gstreamer-1.0
+$ cd gstreamer-1.0
+$ tar xJf gstreamer-1.0-android-universal-1.16.0.tar.xz
+```
+
+Modify the gstreamer-1.0.mk file for NDK build to prevent build error.
+
+```
+$GSTREAMER_ROOT_ANDROID/{Target-ABI}/share/gst-android/ndk-build/gstreamer-1.0.mk
+```
+
+- Remove ```-nostdlib++``` option.
+
+```
+# Remove '-nostdlib++' in GSTREAMER_ANDROID_CMD of the gstreamer-1.0.mk file for the ARM-based Android software stack.
+GSTREAMER_ANDROID_CMD := $(call libtool-link,$(TARGET_CXX) $(GLOBAL_LDFLAGS) $(TARGET_LDFLAGS) -shared ...
+```
+
+- Add directory separator.
+
+```
+# Add separator '/' between $(GSTREAMER_NDK_BUILD_PATH) and $(plugin)
+
+GSTREAMER_PLUGINS_CLASSES    := $(strip \
+            $(subst $(GSTREAMER_NDK_BUILD_PATH),, \
+            $(foreach plugin,$(GSTREAMER_PLUGINS), \
+            $(wildcard $(GSTREAMER_NDK_BUILD_PATH)/$(plugin)/*.java))))
+
+GSTREAMER_PLUGINS_WITH_CLASSES := $(strip \
+            $(subst $(GSTREAMER_NDK_BUILD_PATH),, \
+            $(foreach plugin, $(GSTREAMER_PLUGINS), \
+            $(wildcard $(GSTREAMER_NDK_BUILD_PATH)/$(plugin)))))
+```
+
+- Set SYSROOT_GST_INC and SYSROOT_GST_LINK.
+
+```
+    ifdef SYSROOT_INC
+        SYSROOT_GST_INC := $(SYSROOT_INC)     # Add this line
+        SYSROOT_GST_LINK := $(SYSROOT_INC)    # Add this line
+        #$(call assert-defined, SYSROOT_LINK) # Block this line
+```
+
+#### Download NNStreamer source code
+
+```bash
+$ cd $ANDROID_DEV_ROOT/workspace
+$ git clone https://github.com/nnsuite/nnstreamer.git
+```
+
+#### Build Android API
+
+Run the build script in NNStreamer.
+After building the Android API, you can find the library(.aar) in ```$NNSTREAMER_ROOT/android_lib```.
+
+```bash
+$ cd $NNSTREAMER_ROOT
+$ bash ./api/android/build-android-lib.sh
+```
+
+#### Run the unit-test (Optional)
+
+Before running the unit-test, you should download the test model and copy it into your target device manually.
+
+Make directory and copy test model and label files into the internal storage of your own Android target device.
+
+You can download these files from [nnsuite testcases repository](https://github.com/nnsuite/testcases/tree/master/DeepLearningModels/tensorflow-lite/Mobilenet_v1_1.0_224_quant).
+
+```
+# You must put the below model and label files in the internal storage of your Android target device.
+{INTERNAL_STORAGE}/nnstreamer/test/mobilenet_v1_1.0_224_quant.tflite
+{INTERNAL_STORAGE}/nnstreamer/test/labels.txt
+{INTERNAL_STORAGE}/nnstreamer/test/orange.png
+```
+
+To check the testcases, run the build script with an option ```--run_unittest=yes```.
+You can find the result in ```$NNSTREAMER_ROOT/android_lib```.
+
+```bash
+$ cd $NNSTREAMER_ROOT
+$ bash ./api/android/build-android-lib.sh --run_unittest=yes
+```