1. MainActivity.Java

In your MainActivity.Java file make the below changes

import android.webkit.WebView;
...

webView = (WebView) findViewById(R.id.transfiWidget);
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl("https://buy.transfi.com?apiKey=[YOUR_PRODUCTION_API_KEY]&[QUERY_PARAMETERS]");

2. Activity_main.xml

Add Webview in Activity_main.xml file


<WebView
  xmlns:android="<http://schemas.android.com/apk/res/android>"
  android:id="@+id/transfiWidget"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
/>

3. AndroidManifest.XML

Update your app permission to include network use.

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