android gradle change output apk file name.

build.gradle

android.applicationVariants.all { variant ->
    println "*********" + variant.description + "**********";
    def variants = variant.baseName.split("-");
    def apkName = "ricebook-";
    apkName += variants[0];
    apkName += "-v" + android.defaultConfig.versionName;
    if (!variant.zipAlign) {
        apkName += "-unaligned";
    }
    if (variant.buildType.name == "release") {
        apkName += "-RELEASE.apk";
    } else {
        apkName += "-SNAPSHOT.apk";
    }
    println "*********" + "$project.buildDir/apk/" + apkName + "**********";
    variant.outputFile = file("$project.buildDir/apk/" + apkName)
}

android {

//....

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
productFlavors {
    world {
        versionName "world"
    }
    local {
        versionName "local"
    }
}

applicationVariants.all { variant ->
    println("Iterating variant: " + variant.getName());

    if (variant.getName().contains("world")) {
        variant.buildConfigField "String", "URL_API_PATH", '"http://..."'
    } else {
        variant.buildConfigField "String", "URL_API_PATH", '"http://192.168...."'
    }
    variant.mergedFlavor.versionName = android.defaultConfig.versionName + "-" + variant.mergedFlavor.versionName;

    variant.outputs.each { output ->
        def apkName = "somename_" + android.defaultConfig.versionCode;

        if (variant.buildType.name.equals("release"))
            apkName += "_" + variant.buildType.name;

        apkName += ".apk";
        println "*********" + "$project.buildDir/apk/" + apkName + "**********";
        output.outputFile = file("$project.buildDir/apk/" + apkName)
    }
}

}