dependencies {
  // Add the Auth0 Android SDK
  implementation 'com.auth0.android:auth0:2.+'
}

android {
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
  kotlinOptions {
    jvmTarget = '1.8'
  }
}

// app/build.gradle

apply plugin: 'com.android.application'
compileSdkVersion 30
android {
    defaultConfig {
        applicationId "com.auth0.samples"
        minSdkVersion 21
        targetSdkVersion 30
        // ...

        // ---> Add the next line
        manifestPlaceholders = [auth0Domain: "@string/com_auth0_domain", auth0Scheme: "demo"]
        // <---
    }
}

<uses-permission android:name="android.permission.INTERNET" />

// Import the parts needed by the SDK
import com.auth0.android.Auth0
import com.auth0.android.provider.WebAuthProvider

class MainActivity : AppCompatActivity() {

  private lateinit var account: Auth0

  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)

      // Set up the account object with the Auth0 application details
      account = Auth0(
          "YOUR_CLIENT_ID",
          "YOUR_DOMAIN"
      )
  }
}

private fun loginWithBrowser() {
    // Setup the WebAuthProvider, using the custom scheme and scope.

    WebAuthProvider.login(account)
        .withScheme("demo")
        .withScope("openid profile email")
        // Launch the authentication passing the callback where the results will be received
        .start(this, object : Callback<Credentials, AuthenticationException> {
            // Called when there is an authentication failure
            override fun onFailure(exception: AuthenticationException) {
                // Something went wrong!
            }

            // Called when authentication completed successfully
            override fun onSuccess(credentials: Credentials) {
              // Get the access token from the credentials object.
              // This can be used to call APIs
              val accessToken = credentials.accessToken
            }
        })
}

private fun logout() {
  WebAuthProvider.logout(account)
    .withScheme("demo")
    .start(this, object: Callback<Void?, AuthenticationException> {
      override fun onSuccess(payload: Void?) {
        // The user has been logged out!
      }

      override fun onFailure(error: AuthenticationException) {
        // Something went wrong!
      }
    })
}

private fun showUserProfile(accessToken: String) {
  var client = AuthenticationAPIClient(account)

  // With the access token, call `userInfo` and get the profile from Auth0.
  client.userInfo(accessToken)
    .start(object : Callback<UserProfile, AuthenticationException> {
        override fun onFailure(exception: AuthenticationException) {
            // Something went wrong!
        }

        override fun onSuccess(profile: UserProfile) {
          // We have the user's profile!
          val email = profile.email
          val name = profile.name
        }
  })
}