Android SDK

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Last Modified: 7/10/2021

The EdgeXR Android Client Library enables an app to locate the most optimal server backend. Because these APIs involve networking, most functions will run asynchronously, and in a background thread.

The Matching Engine Android SDK provides everything required to create applications for Android devices.

Note: Devices without a supporting cellular network may use Wifi for development.

Prerequisites

• Android Studio 3.6.x installed

• A device with API v.23 or higher (Android 6.0)

Download the Android SDK Libraries

Step 1: Create a login on to the EdgeXR Console. The creation of a login will automatically generate a user account and allows for access to EdgeXR Artifactory.

Step 2: In your top level Android Studio gradle project file, add the following artifactory plugin to the buildscript section.

buildscript {
  repositories {
    google()
    jcenter()
  }
  dependencies {
    classpath 'com.android.tools.build:gradle:3.4.0'
    classpath "com.google.protobuf:protobuf-gradle-plugin:0.8.8"
    // JFrog Artifactory:
    classpath "org.jfrog.buildinfo:build-info-extractor-gradle:latest.release"
    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
  }
}

Step 3: Append the following two properties to the local.properties file. Additionally, you must include these two properties within your gradle file. Once the properties are added, specify a project level GRPC version, and the EdgeXR SDK matchingEngine version.

Properties properties = new Properties()
properties.load(project.rootProject.file('local.properties').newDataInputStream())
def artifactoryuser = properties.getProperty("artifactoryuser")
def artifactorypassword = properties.getProperty("artifactorypassword")
project.ext.grpcVersion = '1.32.1'
project.ext.matchingengineVersion = '3.0'
project.ext.melVersion = '1.0.11'

Step 4: Add the EdgeXR repository.

allprojects {
   apply plugin: 'com.jfrog.artifactory'
   apply plugin: 'maven-publish'
   repositories {
       google()
       jcenter()
       mavenLocal()
       maven {
           credentials {
               // Create these variables in local.properties if you don't have them.
               username artifactory_user
               password artifactory_password
           }
           url "https://console.cloud.edgexr.org/storage/v1/artifacts/artifactory/maven-releases/"
       }
   }
}

Step 5: In the application build.gradle project file, add the following to the dependencies section so that the EdgeXR related libraries can be downloaded. Click sync gradle file if prompted by the Android Studio IDE.

dependencies {
   // ...
   implementation "com.mobiledgex:matchingengine:${matchingengineVersion}"
   implementation 'com.mobiledgex:mel:${melVersion}'
   implementation "io.grpc:grpc-okhttp:${grpcVersion}"
   implementation "io.grpc:grpc-stub:${grpcVersion}"
   implementation "io.grpc:grpc-protobuf-lite:${grpcVersion}"
}

Example SDK Usage

Workflow to Find the Closest Cloudlet

MatchingEngine me = new MatchingEngine(context); 
//For privacy reasons, there is a flag the application should ask the user for permission before enabling, concerning location usage. 
MatchingEngine.setMatchingEngineLocationAllowed(matchingEngineLocationAllowed);

//Register Client
AppClient.RegisterClientRequest registerClientRequest = me.createDefaultRegisterClientRequest(context, organizationName).setAppName(appName).setAppVers(appVersion).build();      
registerReply = me.registerClient(registerClientRequest, GRPC_TIMEOUT_MS);

//Find Cloudlet 
AppClient.FindCloudletRequest findCloudlet= matchingEngine.createDefaultFindCloudletRequest(ctx, location).build();
findCloudletReply = me.findCloudlet(findCloudletRequest, GRPC_TIMEOUT_MS);

Workflow to Utilize Edge Events

mEdgeEventsSubscriber = new EdgeEventsSubscriber(); me.getEdgeEventsBus().register(mEdgeEventsSubscriber);
// set a default config.
// There is also a parameterized version to further customize.
EdgeEventsConfig backgroundEdgeEventsConfig = me.createDefaultEdgeEventsConfig();
backgroundEdgeEventsConfig.latencyTestType = NetTest.TestType.CONNECT;
// This is the internal port, that has not been remapped to a public port for a particular appInst.
backgroundEdgeEventsConfig.latencyInternalPort = 3765; // 0 will grab first UDP port but will favor the first TCP port if found.
// Latency config. There is also a very similar location update config.
backgroundEdgeEventsConfig.latencyUpdateConfig.maxNumberOfUpdates = 0; // Default is 0, which means test forever.
backgroundEdgeEventsConfig.latencyUpdateConfig.updateIntervalSeconds = 7; // The default is 30.
backgroundEdgeEventsConfig.latencyThresholdTrigger = 186;

For more information on how to use the Android SDK and best practices, please refer to the Android SDK Manual.