Android Studio 3.0 Flavor Dimension Issue

If you want not to use dimensions you should use this line

android { 
compileSdkVersion 24

...
flavorDimensions "default"
...
}

but if you want ti use dimensions you should declare your dimension name first and then use this name after THIS example is from the documentations:

android {
...
buildTypes {
debug {...}
release {...}
}

  // Specifies the flavor dimensions you want to use. The order in which you
  // list each dimension determines its priority, from highest to lowest,
  // when Gradle merges variant sources and configurations. You must assign
  // each product flavor you configure to one of the flavor dimensions.
  flavorDimensions "api", "mode"

  productFlavors {
    demo {
  // Assigns this product flavor to the "mode" flavor dimension.
  dimension "mode"
  ...
}

full {
  dimension "mode"
  ...
}

// Configurations in the "api" product flavors override those in "mode"
// flavors and the defaultConfig block. Gradle determines the priority
// between flavor dimensions based on the order in which they appear next
// to the flavorDimensions property above--the first dimension has a higher
// priority than the second, and so on.
minApi24 {
  dimension "api"
  minSdkVersion 24
  // To ensure the target device receives the version of the app with
  // the highest compatible API level, assign version codes in increasing
  // value with API level. To learn more about assigning version codes to
  // support app updates and uploading to Google Play, read Multiple APK Support
  versionCode 30000 + android.defaultConfig.versionCode
  versionNameSuffix "-minApi24"
  ...
}

minApi23 {
  dimension "api"
  minSdkVersion 23
  versionCode 20000  + android.defaultConfig.versionCode
  versionNameSuffix "-minApi23"
  ...
}

minApi21 {
  dimension "api"
  minSdkVersion 21
  versionCode 10000  + android.defaultConfig.versionCode
  versionNameSuffix "-minApi21"
  ...
    }
  }
}
...

I have used flavorDimensions for my application in build.gradle (Module: app)

flavorDimensions "tier"

productFlavors {
    production {
        flavorDimensions "tier"
        //manifestPlaceholders = [appName: APP_NAME]
        //signingConfig signingConfigs.config
    }
    staging {
        flavorDimensions "tier"
        //manifestPlaceholders = [appName: APP_NAME_STAGING]
        //applicationIdSuffix ".staging"
        //versionNameSuffix "-staging"
        //signingConfig signingConfigs.config
    }
}

Check this link for more info

// Specifies two flavor dimensions.
flavorDimensions "tier", "minApi"

productFlavors {
     free {
            // Assigns this product flavor to the "tier" flavor dimension. Specifying
            // this property is optional if you are using only one dimension.
            dimension "tier"
            ...
     }

     paid {
            dimension "tier"
            ...
     }

     minApi23 {
            dimension "minApi"
            ...
     }

     minApi18 {
            dimension "minApi"
            ...
     }
}

in KotlinDSL you can use like this :

flavorDimensions ("PlaceApp")
productFlavors {
    create("tapsi") {
        setDimension("PlaceApp")
        buildConfigField("String", "API_BASE_URL", "https://xxx/x/x/")
    }

}

If you have simple flavors (free/pro, demo/full etc.) then add to build.gradle file:

android {
...
flavorDimensions "version"
productFlavors {
        free{
            dimension "version"
            ...
            }
        pro{
            dimension "version"
            ...
            }
}

By dimensions you can create "flavors in flavors". Read more.