FlutterStarter/android/build.gradle

buildscript {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'
    }
}

allprojects {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
    project.evaluationDependsOn(':app')
}

task clean(type: Delete) {
    delete rootProject.buildDir
}