Using Android `sdk.dir` property to locate EMDK's jar Library.

2019 Update #

This post is now obsolete. Please refer to Zebra’s EMDK documentation for updated information.

Note this post has been published on Zebra developer portal, if you’ve any comment, probably best to post them over there.

Working in Android Studio you can notice that every project contains a local.properties file with at least a couple of properties containing the path for Android SDK and Android NDK.

Android Studio populates this information when it creates the project based on the ANDROID_HOME environment variable. If this variable is not present in your system Android Studio will find the correct path in other ways, but having ANDROID_HOME setup correctly is a really good idea, see the note at the end of this short post.

Given that I usually have in my build.gradle file a reference to Zebra’s EMDK, look like a good idea to use sdk.dir instead than hardcoding the path (like I’ve done for a too much long time) given that the EMDK resides in Android SDK’s add-ons folder.

So, my gradle files now includes:

Properties properties = new Properties() properties.load(project.rootProject.file('local.properties').newDataInputStream())
def sdkDir = properties.getProperty('sdk.dir')

so that I can the use the sdkDir variable like:

provided fileTree(include: ['com.symbol.emdk.jar'], dir: sdkDir+'/add-ons/addon-symbol_emdk-symbol-23/libs/')

Much cleaner and nice :-)

A note on ANDROID_HOME #

It’s not usually a good idea to include in your revision system the local.properties file because this contains information… “local”… to your machine. Imagine that you’re sharing a project with a colleague or with a remote CI build server. In this case everybody will have the Android SDK (and the Zebra’s EMDK that resides in the SDK add-ons) in a different folder.

The best option in this case is to avoid to share the local.properties file and have the ANDROID_HOME environment variable correctly setup so that the build works correctly on every machine.

• If local.properties is not available, Gradle will use ANDROID_HOME automatically.
• If local.properties is available, Gradle will use this file having a wrong sdk.dir set and fail.

Update #

I got some enquiry to provide a complete gradle file to understand where to do the pasting. Here’s one sample file:

    apply plugin: 'com.android.application'

    Properties properties = new Properties()
    properties.load(project.rootProject.file('local.properties').newDataInputStream())
    def sdkDir = properties.getProperty('sdk.dir')

    android {
        compileSdkVersion 26
        buildToolsVersion "26.0.1"
        defaultConfig {
            applicationId "com.pietromaggi.sample.barcode"
            minSdkVersion 19
            targetSdkVersion 22
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        }
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            }
        }
    }

    dependencies {
        compile fileTree(dir: 'libs', include: ['*.jar'])

        provided fileTree(include: ['com.symbol.emdk.jar'], dir: sdkDir+'/add-ons/addon-symbol_emdk-symbol-23/libs/')

        androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
            exclude group: 'com.android.support', module: 'support-annotations'
        })
        compile 'com.android.support:appcompat-v7:26.+'
        compile 'com.android.support.constraint:constraint-layout:1.0.2'
        testCompile 'junit:junit:4.12'
    }