FriendlyThings APIs

1 Introduction

FriendlyThings is an Android SDK developed by FriendlyElec to access hardware. Users can use it to access various hardware resources Uart, SPI, I2C, GPIO etc on a FriendlyElec ARM board under Android. This SDK is based on Android-NDK. Users can use it to develop popular IoT applications without directly interacting with drivers.

2 Quick Start

2.1 Step 1: Include libfriendlyarm-things.so in APP

Clone the following library locally:

git clone https://github.com/friendlyarm/friendlythings-sdk

Copy all the files under the libs directory to your working directory and create a "com/friendlyarm" directory in your Android project's src directory, copy the whole "java/FriendlyThings" to your newly created "com/friendlyarm" directory. The whole project directory will look like this(Note:AndroidStudio's project may be a little bit different):

YourProject/
├── AndroidManifest.xml
├── libs
│   ├── arm64-v8a
│   │   └── libfriendlyarm-things.so
│   └── armeabi
│       └── libfriendlyarm-things.so
├── src
│   └── com
│       └── friendlyarm
│           ├── FriendlyThings
│           │   ├── BoardType.java
│           │   ├── FileCtlEnum.java
│           │   ├── GPIOEnum.java
│           │   ├── HardwareControler.java
│           │   ├── SPIEnum.java
│           │   ├── SPI.java
│           │   └── WatchDogEnum.java

Import the following components and the major APIs are included in the HardwareControler.java file:

import com.friendlyarm.FriendlyThings.HardwareControler;
import com.friendlyarm.FriendlyThings.SPIEnum;
import com.friendlyarm.FriendlyThings.GPIOEnum;
import com.friendlyarm.FriendlyThings.FileCtlEnum;
import com.friendlyarm.FriendlyThings.BoardType;

2.2 Step 2: Give APP System Right

Your app needs the system right to access hardware resources;
Give your app the system right by making changes in the AndroidManifest.xml file and the Android.mk file;
It is better to include your app in your Android source code and compile them together. If your app is not compiled together with your Android source code you have to go through tedious steps to compile your app and sign your app to give it the system right.

2.2.1 Modify AndroidManifest.xml

Add the following line in the manifest node in the AndroidManifest.xml file:

android:sharedUserId="android.uid.system"

2.2.2 Modify Android.mk

Create an Android.mk file(the simplest way is to copy a sample Android.mk file), modify the Android.mk file by adding a line LOCAL_CERTIFICATE := platform :

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
 
LOCAL_SRC_FILES := $(call all-subdir-java-files)
 
LOCAL_PACKAGE_NAME := Project Name
 
LOCAL_CERTIFICATE := platform
LOCAL_MODULE_TAGS := optional
LOCAL_CFLAGS := -lfriendlyarm-hardware
 
include $(BUILD_PACKAGE)

2.3 Final Step: Compile Your APP Together with Android Source Code

Go to Android source code's root directory and run "setenv.sh" to export environmental variables, enter your app's directory and run "mm" to compile:
For example: compile the GPIO_LED_Demo on RK3399:

cd rk3399-android-8.1
. setenv.sh
cd vendor/friendlyelec/apps/GPIO_LED_Demo
mm

2.4 Sample project in Android Studio

https://github.com/friendlyarm/AndroidStudio-GPIODemo