Use signing.properties file which controls which keystore to use to sign the APK with gradle.

build.gradle

android {

    signingConfigs {
        release
    }

    buildTypes {
            release {
                signingConfig signingConfigs.release
            }
    }
}

def Properties props = new Properties()
def propFile = new File('signing.properties')
if (propFile.canRead()){
    props.load(new FileInputStream(propFile))

    if (props!=null && props.containsKey('STORE_FILE') && props.containsKey('STORE_PASSWORD') &&
            props.containsKey('KEY_ALIAS') && props.containsKey('KEY_PASSWORD')) {
        android.signingConfigs.release.storeFile = file(props['STORE_FILE'])
        android.signingConfigs.release.storePassword = props['STORE_PASSWORD']
        android.signingConfigs.release.keyAlias = props['KEY_ALIAS']
        android.signingConfigs.release.keyPassword = props['KEY_PASSWORD']
    } else {
        println 'signing.properties found but some entries are missing'
        android.buildTypes.release.signingConfig = null
    }
}else {
    println 'signing.properties not found'
    android.buildTypes.release.signingConfig = null
}

signing.properties

STORE_FILE=/path/to/your.keystore
STORE_PASSWORD=yourkeystorepass
KEY_ALIAS=projectkeyalias
KEY_PASSWORD=keyaliaspassword

Thanks!

Thank you!! this solved my problem

Thank you, this helped me solve exactly the same problem you had.

Very good thanks alot it also solved my problem the way

here's another solution
http://stackoverflow.com/a/21020469/2019549

When I build project found error message

Error:(17, 0) Could not get unknown property 'release' for SigningConfig container of type org.gradle.api.internal.FactoryNamedDomainObjectContainer.

Great solution @gabrielemariotti thanks for sharing this!
This is how I did it: zdavatz/generika_android@e16af6f

thanks!

Awesome! Thank you!