build.gradle useful solutions

build.gradle

// change java source
android{
  compileOptions {
      sourceCompatibility JavaVersion.VERSION_1_8
      targetCompatibility JavaVersion.VERSION_1_8
  }
  kotlinOptions {
      jvmTarget = "1.8"
  }
}

// change output name
android.applicationVariants.all { variant ->
    variant.outputs.all {
        outputFileName = "MyAppName-${variant.name}-${variant.versionCode}.apk"
    }
}