Unresolved reference: BR (Android Studio)

After researching quite a bit, turns out there are a couple things to add in order to use data binding library

project build.gradle

buildscript {
    ext {
        compiler_version = '3.1.3'
    }
    dependencies {
        classpath "com.android.tools.build:gradle:$compiler_version"
    }
}

app build.gradle

apply plugin: 'kotlin-kapt'

android {
    dataBinding {
        enabled = true
    }
}

dependencies {
    kapt "com.android.databinding:compiler:$compiler_version"
}

kapt {
    generateStubs = true
}

I started to have some warnings after adding the data binding library, like 3rd-party Gradle plug-ins may be the cause and Classpath entry points to a non-existent location. But compiles and runs fine

Android Studio failed to import my BR class automatically. All solutions provided above failed. I just had to import the class manually, Android studio had created it correctly.

SAMPLE:

package your_packagename

import your_packagename.BR
import ...
...

I think this happened due to Copy and Paste. When i typed BR manually, Android Stdio did the Automatic Import.

For Android Studio 3.3, Gradle 3.3.0 and Databinding v2, the only line that needs to be added to fix this issue is in your (app's or modules) build.gradle:

apply plugin: "kotlin-kapt"