Integrating FastLink 4 for Android

FastLink can be integrated into your Android application through WebView. Prerequisites to integrate FastLink is Android 7.0+.

Integration Steps

Follow the steps to integrate FastLink into an Android application. The code samples here use the Java language. FastLink can equally be loaded from the corresponding Kotlin code.

Step 1: Generate an Access Token

FastLink uses the client credentials authentication mechanism. You must pass a valid accessToken to authenticate your invocation of the FastLink application. Generate the access token by following the instructions provided in the Getting Started with Client Credentials page.

Step 2: Create the `WebView` Instance

You can either programmatically create the WebView instance or add it through the Layout Editor.

import android.webkit.WebView;

public class WebViewActivity extends AppCompatActivity {

    public WebView webview;
    public static Uri.Builder builder;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        .....

        webview = (WebView) findViewById(R.id.webview);
        webview.setWebViewClient(webViewClient);

        .....
    }

    WebViewClient webViewClient = new WebViewClient() {
        //You can override the WebViewClient methods here
    }
}

Step 3: Create the Request Object

Once the WebView instance is created, you have to create the request object.

try {
    builder = new Uri.Builder()
        .appendQueryParameter("accessToken", "Bearer {{ACCESS_TOKEN}}")
        .appendQueryParameter("extraParams", URLEncoder.encode( "configName=<config-name-from-config-tool>", "UTF-8"));

} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}
String query = builder.build().getQuery();

Step 4: Load the Request Object in the `WebView` Instance

Once the request object is ready, load this it in the WebView instance. This will render the FastLink inside WebView.

webview.postUrl("FASTLINK_URL", query.getBytes());

Passing Additional Params to FastLink

While creating the request object, additional params like deep-linking flow attributes, callback details, etc., can be passed as query parameters along with the mandatory configName parameter. Following is a sample code snippet for the add deep-link flow.

try {
    builder = new Uri.Builder()
        .appendQueryParameter("accessToken", "Bearer {{ACCESS_TOKEN}}")
        .appendQueryParameter("extraParams", URLEncoder.encode( "configName=<config-name-from-config-tool>&flow=add&providerId=16441", "UTF-8"));

} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}

For more details, refer to the Additional Params section in FastLink 4 Advanced Integration.

Handling Open Banking Sites

The intentUrl attribute is used get the control back to the native app from an external application. Example, native browser.

Passing intentUrl as part of extraParams

try {
    builder = new Uri.Builder()
        .appendQueryParameter("accessToken", "Bearer {{ACCESS_TOKEN}}")
        .appendQueryParameter("extraParams", URLEncoder.encode( "configName=<config-name-from-config-tool>&intentUrl=<protocol://domainname>", "UTF-8"));

} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}

When the user selects an Open Banking site, FastLink will send a post message with the site's OAuth URL which needs to be opened in a native browser.

Post Message - OPEN_EXTERNAL_URL

{
    "type": "OPEN_EXTERNAL_URL",
    "data": {
        "url": "<OAUTH URL>"
    }
}

Once the user logs in, authorize consent, and completes the flow, use intentUrl as callback URL.

Native app should listen to this intentUrl by which the control comes back to the native app.

Handling Callback

Entries in AndroidManifest.xml.

<activity
        android:name="com.yodlee.fastlink.InAppBrowserActivity"
        android:configChanges="keyboardHidden|orientation|screenSize"
        android:label="@string/app_name"
        android:windowSoftInputMode="adjustResize|adjustPan">
            <intent-filter>
                <data
                        android:host="<domainname>"
                        android:scheme="<protocol>" />

                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.BROWSABLE" />
               <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

Handling Events from FastLink

To communicate with the events from FastLink, your application has to listen for the JSInterfaceHandler delegate method. Note that the name should be YWebViewHandler as FastLink will check for this name and send the events.

class JSInterfaceHandler {
    Context mContext;

    JSInterfaceHandler(Context c) {
        mContext = c;
    }

    @JavascriptInterface
    public void postMessage(final String data) {
        //Data will contain all the communication messages sent from FastLink
        Log.d("FL:MESSAGE", data);
    }
}

Add the JSInterfaceHandler config to the WebView instance.

webview.addJavascriptInterface(new JSInterfaceHandler(this), "YWebViewHandler");

Post Message Events

The FastLink application shares the account addition status to your application using the POST_MESSAGE events.

{
    "type": "POST_MESSAGE",
    "data": {
        //Post Message data
    }
}

External URL

You must open the URL in the Chrome Custom Tabs or in the default mobile browser. You MUST NOT open the external URL within the Andriod WebView. Doing so will result in blocked requests from many data providers due to security vulnerabilities.

{
    "type": "OPEN_EXTERNAL_URL",
    "data": {
        "url": "<External URL>"
    }
}