Facebook friends dialog returns “Unknown method” error

The underlying problem is that the Facebook API is not yet ready for all the display types, and the friends dialog cannot be shown for the mobile display. What you can do is to change the Facebook android library: if you use “popup” display mode instead of “touch” and www.facebook.com instead of m.facebook.com while opening the dialog, a proper window will appear in the Facebook librarys standard WebView.

For this, change the dialog function of Facebook.java as follows:

protected static String DIALOG_BASE_URL = "https://m.facebook.com/dialog/";
protected static String DIALOG_BASE_URL_FOR_MISSING_SCREENS = "https://www.facebook.com/dialog/";

public void dialog(Context context, String action, Bundle parameters,
        final DialogListener listener) {

    boolean missingScreen = action.contentEquals("friends") ? true : false;

    String endpoint = missingScreen ? DIALOG_BASE_URL_FOR_MISSING_SCREENS : DIALOG_BASE_URL;
    endpoint += action;

    parameters.putString("display", missingScreen ? "popup" : "touch");
    parameters.putString("redirect_uri", REDIRECT_URI);

    if (action.equals(LOGIN)) {
        parameters.putString("type", "user_agent");
        parameters.putString("client_id", mAppId);
    } else {
        parameters.putString("app_id", mAppId);
    }

    if (isSessionValid()) {
        parameters.putString(TOKEN, getAccessToken());
    }
    String url = endpoint + "?" + Util.encodeUrl(parameters);
    if (context.checkCallingOrSelfPermission(Manifest.permission.INTERNET)
            != PackageManager.PERMISSION_GRANTED) {
        Util.showAlert(context, "Error",
                "Application requires permission to access the Internet");
    } else {
        new FbDialog(context, url, listener).show();
    }
}

After that you might want to remove the double title bar from the dialog as well. Go to FbDialog.java, and insert something similar to onPageFinished:

if (url.contains("friends?")) {
    mTitle.setHeight(0);
    mTitle.setVisibility(View.INVISIBLE);
}