> ## Documentation Index
> Fetch the complete documentation index at: https://developers.loyaltylion.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Setup

The LoyaltyLion SDK supports bi-directional communication with your mobile app
to facilitate more advanced features.

For example, with Shopify mobile apps this can be used to have LoyaltyLion ask
your app to add a voucher code or free product to the current cart.

## Setting up a WebView for advanced features

<Tabs>
  <Tab title="iOS WKWebView">
    When LoyaltyLion is embedded in a `WKWebView`, we'll use the [WKScriptMessageHandler](https://developer.apple.com/documentation/webkit/wkscriptmessagehandler)
    interface to send messages to your app.

    You'll need to register the listeners you want to support with your content controller, and then handle
    them appropriately. The example below listens to the `ready` event to detect when the Loyalty Page has finished loading.

    ```swift theme={null}
    class ViewController: UIViewController, WKScriptMessageHandler {
      override func viewDidLoad() {
        let contentController = WKUserContentController()

        // subscribe to LoyaltyLion events
        contentController.add(self, name: "sdkReady")

        // continue creating WKWebView instance...
      }

      func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        if message.name == "ready" {
          print("LoyaltyLion SDK is ready")
        }
      }
    }
    ```
  </Tab>

  <Tab title="Android WebView">
    When LoyaltyLion is embedded in an Android WebView, you can add a `LoyaltyLionBridge` JavaScript interface which we'll use to emit events.

    The example below sets up a WebView, registers the `LoyaltyLionBridge` and registers a `ready` handler to detect when the Loyalty Page has finished loading.

    ```kotlin theme={null}
    class MainActivity : AppCompatActivity() {
        lateinit var webView: WebView

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

            webView = WebView(this)
            setContentView(webView)

            webView.settings.javaScriptEnabled = true
            webView.addJavascriptInterface(LoyaltyLionBridge(), "LoyaltyLionBridge")

            webView.loadDataWithBaseURL(null, "...", "text/html", "utf-8", null)
        }

        inner class LoyaltyLionBridge {
            @JavascriptInterface
            fun sdkReady() {
                Log.d("WebView", "LoyaltyLion SDK ready")
            }
        }
    }
    ```
  </Tab>
</Tabs>