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Creating Apps From Scratch

If you decide not to use the Wizard, you can still create a new Android Studio project and then build an app using the SDK libraries, or add the SDK to an existing project. To do this, you'll need to modify the top-level and module-level build.gradle files manually to include all required repositories, dependencies, and settings.

The top-level file stores configuration options common to all sub-projects/modules. The module-level file stores options for your new app.

To generate proxy class Java files, use either the OData Gradle Plugin or the Proxy Generator CLI tool. Both tools are included in the software package.

To use the OData Gradle Plugin, modify the two build.gradle files to add the plugin as a dependency and configure it as required. To use the Proxy Generator CLI tool, open a command prompt and enter the required command. See Using the OData Proxy Class Generator Command-line Tool for more information.

Prerequisites

You have run the installation script to install the SDK. See Installing the SAP BTP SDK for Android for more information.

Procedure

  1. From the Android Studio Welcome screen, select Start a new Android Studio project and complete the Create New Project wizard. Refer to your Android Studio documentation for further information.
  2. From the project tool window, navigate to the appropriate folder and open the build.gradle file in the editor window.

    For the top-level file, go to <yourproject> > gradle. For the module-level app, go to <yourproject> > app.

  3. Add the required dependencies to the project

  4. Generate OData proxy classes. See Using the Gradle Tool to Generate Proxy Classes for more information.
  5. To ensure you can debug your new project, enable trace logging for your project; see Debugging.

Adding Required Repositories to Your Project

Add all required repositories including the local Maven repository to your project by modifying the app module build.gradle file for your project.

From Android Studio, open the top-level build.gradle file and add the following to all the repositories blocks:

buildscript {
    repositories {
        google()
        jcenter()
        mavenLocal()
    }
}
allprojects {
    repositories {
        google()
        jcenter()
        mavenLocal()
    }
}

Alternatively, we offer a better similar way to well-known public repositories such as Maven Central, Bintray and JCenter: The SAP Cloud Shipment channel. In this very specific case of the Android SDK, we are talking about a customer-facing Maven repository that you can configure in your projects to consume the SAP BTP SDK for Android without any additional manual downloads. We finally publish Android SDK libraries via SAP-hosted Maven infrastructure in the DMZ. The process to use this is:

  • Obtain a technical user from the SAP Repositories Management site, and download the Basic Auth Password file. See Creating Required Credentials for further details.
  • Set the user credentials in ENV (SAP_MAVEN_USER, SAP_MAVEN_PASSWORD)
  • Create a $HOME/.gradle/init.gradle script with the following contents:
allprojects {
     ext.SAPRepoConfig = {
         maven {
             url "https://73555000100800001281.maven.repositories.sapcdn.io"
             credentials {
                 username "$System.env.SAP_MAVEN_USER"
                 password "$System.env.SAP_MAVEN_PASSWORD"
             }
         }
     }
     buildscript.repositories SAPRepoConfig
     repositories SAPRepoConfig
 }

Now all Android projects will also fetch dependencies from SAP infrastructure.

Note

You can add the above Maven project to your project repositories in the app module build.gradle file, the above settings can be maintained on the project level.

Adding Project Dependencies

Add one or more of the SDK for Android components as required for your mobile application. The SDK includes the following libraries:

Library Gradle Dependency Line
Fiori com.sap.cloud.android:fiori:3.4.0
Foundation com.sap.cloud.android:foundation:3.4.0
OData com.sap.cloud.android:odata:3.4.0
Offline OData com.sap.cloud.android:offline-odata:3.4.0
Onboarding com.sap.cloud.android:onboarding:3.4.0
Flows com.sap.cloud.android:flowsv2:3.4.0
Google Vision com.sap.cloud.android:google-vision:3.4.0

Add the following SDK libraries as dependencies to your module-level build.gradle file:

dependencies {
    def versions =  [sapCloudAndroidSdk: '3.4.0']

    implementation "com.sap.cloud.android:fiori:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:foundation:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:odata:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:offline-odata:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:onboarding:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:flowsv2:$versions.sapCloudAndroidSdk"
    implementation "com.sap.cloud.android:google-vision:$versions.sapCloudAndroidSdk"
}

If you intend to enable logging, include logback-android dependencies to this enclosure:

dependencies {
    ...
    implementation 'com.github.tony19:logback-android:2.0.0'
}

Using these libraries will require multiDex. To enable this for your project, add the following to the defaultConfig section of your module-level build.gradle file:

android {
    defaultConfig {
        ...
        multiDexEnabled true
    }
    ...
}

Update the target SDK version and compatibility versions as follows to your module-level build.gradle file:

android {
    compileSdkVersion 28
    ...
    compileOptions {
        targetCompatibility 1.8
        sourceCompatibility 1.8
    }
}

Initializing SDK

Since there are many modules in the Foundation component, using them in the client code to integrate your application with SAP Mobile Services will require lots of boilerplate code in the mobile application. To reduce the boilerplate code from your mobile application, a new API SDKInitializer.start is introduced as below:

object SDKInitializer {
    fun start(
        application: Application,
        vararg services: MobileService,
        apiKey: String? = null) {
        ...
    }
}

The parameters are explained below:

  1. Application

    This parameter represents the running Android app.

  2. MobileService... services

    This parameter represents all the services to be initialized in your application. Currently the following services are supported:

    This parameter takes a service object, which contains configuration properties for most of the services, as the value. For example, the UsageService can configure auto session features and set the usage store name. If you want to use customized configurations, you can do so before calling the start method.

    Please follow the links above to see the details.

  3. API Key

    This parameter represents the optional API key, which allows apps to interact with mobile services before authentication is performed. Each MobileService can make use of the API key to interact with mobile services during the initialization process.

    This parameter will be saved to SettingsParameter automatically when the client code saves the SettingsParameter instance into SettingsProvider. The client code can then retrieve the API key from SettingsParameter.

    SettingsProvider.get().apiKey?.also { apiKey ->
        //add APIkeyInterceptor into okHttpClient, and save it back into ClientProvider
        val httpClient = ClientProvider.get().addUniqueInterceptor(APIKeyInterceptor(apiKey), save = true)
        //call API with the above httpClient
        ...
        //remove the interceptor and save back to ClientProvider
        ClientProvider.get().removeInterceptorByType(APIKeyInterceptor::class, save = true)
    }
    

Generating Proxy Classes

You can generate proxy class Java files based on OData metadata using either the OData Gradle Plugin or the Proxy Generator CLI tool. Both tools are included in the software package.

These generated proxy classes help consume a specific OData service. Use the OData service’s metadata document to generate your data model. The generated code includes strongly typed functions to perform any OData operation on the data objects.

Info

Proxy classes are automatically added to projects generated with the Wizard Android Studio plugin.

Using the OData Gradle Plugin

The OData Gradle Plugin supports OData proxy class generation with the Gradle build.

OData service metadata must be saved in a file in the project. Metadata can be downloaded from the OData service metadata URL. Check with your OData service developer or your SAP system administrator for the URL.

If service definition results in changing metadata, the file must be updated to save new metadata. In the case metadata is spread across multiple files, save all the files in the project and reference the top-level file in schemaFile. The proxy generation task executes when the file content changes.

Adding the OData Gradle Plugin

To add the OData Gradle plugin to your project, edit the top-level build.gradle file of your new Android Studio project with the following:

buildscript {
    dependencies {
        classpath 'com.sap.cloud.android:odata-android-gradle-plugin:${versions.sapCloudAndroidSdk}'
    }
}

Configuring the OData Gradle Plugin

To configure the plugin task for proxy class generation, add an odata closure to the module-level build.gradle file as indicated in the example in this section.

OData Plugin Configuration

Property Description
verbose Turn on verbose logging. Default is false.
services Configures the OData task to generate proxy classes for the app
testServices Configures the OData task to generate proxy classes for local tests
androidTestServices Configures the OData task to generate proxy classes for Android connected tests

Service Proxy Class Generation Configuration

Property Description
schemaFile The metadata file for the OData service. Located at the $metadata endpoint of the OData service.
packageName Output package name (defaults to CSDL Schema Namespace)
serviceClass Service class name (defaults to entity container name)
nullableProperties All complex/entity properties are nullable (and no exception is thrown when undefined). Default is false.
disableOpenEnumeration Enumeration types permit member addition. Set this option for non-extensible enumerations. Default is false.
additionalParameters List of additional parameters to be passed to proxy class compiler. Default is none.

The following example shows some of the basic configuration elements for proxy class generation from a metadata file.

apply plugin: 'com.sap.odata.android'

odata {
    verbose true
    services {
        products {
            schemaFile file("src/main/odata/productssvcmetadata.xml")
            packageName "com.example.products"
            serviceClass "ProductsService"
        }
        orders {
            schemaFile file("src/main/odata/orderssvcmetadata.xml")
            packageName "com.example.orders"
            serviceClass "OrdersService"
        }
    }
}

In some cases generation may fail and suggest internal options that can be provided to additionalParameters.

Example:

additionalParameters = ["-parser:ALLOW_CASE_CONFLICTS"]

Using the OData Proxy Class Generator Command-Line Tool

You can also generate your proxy classes by running the OData Proxy Class Generator tool. Ensure you have a current Java installation and that it is in your system’s path.

The proxygenerator uses the following options:

Options Description
-m Metadata: metadata file
-d Destination: The destination where the proxy classes will be generated. (defaults to the current path)
-h Help
-np Nullable properties: All complex/entity properties are nullable. No exception is thrown when undefined. The default is false
-p Package: The output package name. Defaults to the CSDL Schema Namespace.
-s Service: The service class name. Defaults to the entity container name.
-v Verbose: Verbose mode on. The default is false.

To generate proxy classes using the OData Proxy Class Generator tool:

  1. Download the desired OData service metadata document from its URL and save it in a file (for example, MyMetadata.xml).
  2. Enter the following command in terminal to generate the Java proxy classes:

    • For Mac:

          $SAP_ANDROID_HOME/tools/proxygenerator/bin/proxygenerator -m <path to MyMetadata.xml> -s <MyServiceName> \
              -p <Generated Proxy Class Package Name> -d <Generated Proxy Destination>`
      
    • For Windows:

          proxygenerator.bat -m <path to MyMetadata.xml> -s <MyServiceName> -p <Generated Proxy Class Package Name> `
              -d <Generated Proxy Destination>
      

    where:

    1
    2
    3
    * `SAP_ANDROID_HOME` is environment variable set to point to the folder where SDK is unzipped.
    * `MyMetadata.xml` is the downloaded metadata document.
    * `MyServiceName` is the generated service class name.
    
  3. Find the generated .java file(s) by default in the current folder or whatever the -d option is set to.

Creating the Required Credentials of Technical Users for SAP Cloud Shipment

You can create technical users on SAP Repositories Management site

Procedure for Creating a Technical User

  1. In your browser, navigate to the SAP Repositories Management site

  2. Enter the page of User management, initial opening of the "User management" page will automatically prompt a box for creating a technical user. You have to fill a name for it being aware that the id of your company will be added as a prefix. The name can contain only uppercase and lowercase letters as well as numbers and should be between 3 and 10 symbols long, and then click "Submit" button.

  3. Successful creation will result in a success dialog which means that the technical user was created and distributed to the back-end systems, click "OK" button on this Success dialog.

    Note

    More users can be added by clicking the button "Add" on the left of User management page bottom.

  4. Click "Download" button in the line of Basic Auth Password to download credential, which is save to a file on your local file system:

Download credentials

in the form username_credential_type:

Basic authentication credentials


Last update: June 28, 2021