AdMob Native Ads in Xamarin Forms (Android)

Until recently NativeAds were in a closed beta and only certain developers had access to the ad format, but now, it’s available to everyone. Here’s how you can go about adding one to you Android Xamarin Forms app using a custom renderer.

Step 1: Create a view to act as a placeholder for the ad

This plays two roles. On one hand it’s a view class which we can use to bind the custom renderers and on the other hand it also acts as a placeholder by reserving the space and displaying the “AD” text so the UI doesn’t jump around when the ad gets loaded.

public class NativeAdView : ContentView
{
    public NativeAdView()
    {
        this.HeightRequest = 360;
        this.Margin = new Thickness(8, 8, 8, 0);

        SetPlaceholderContent();
    }

    private void SetPlaceholderContent()
    {
        var placeholderGrid = new Grid();
        var placeHolderText = new Label
        {
            Text = "AD",
            FontSize = 48,
            FontAttributes = FontAttributes.Bold,
            TextColor = Color.White,
            Opacity = 0.3,
            VerticalOptions = new LayoutOptions(LayoutAlignment.Center, true),
            HorizontalOptions = new LayoutOptions(LayoutAlignment.Center, true)
        };

        placeholderGrid.Children.Add(placeHolderText);

        this.Content = placeholderGrid;
    }
}
Code language: C# (cs)

Note: I’ve hardcoded that 360 height in the view for convenience because I am actually using it in a ListView in which all items have the same height. You can remove that and set the height in XAML or when adding the element.

Step 2: Create an ad layout

For this, go into your Android project Resources > layout and create a new file called: ad_unified.axml. You can use the following as a starting layout and modify it as you see fit to match your application.

<com.google.android.gms.ads.formats.UnifiedNativeAdView android:hardwareAccelerated="false"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.CardView
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:cardPreventCornerOverlap="false"
        app:cardCornerRadius="12dp">

        <LinearLayout
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:background="#FFFFFF">

            <AbsoluteLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">

                <com.google.android.gms.ads.formats.MediaView
                    android:id="@+id/ad_media"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:gravity="left"
                    android:text="Ad"
                    android:textColor="#FFFFFF"
                    android:background="#FFCC66"
                    android:textSize="14sp"
                    android:padding="4dp" />
            </AbsoluteLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:padding="5dp">

                <LinearLayout
                    android:layout_height="wrap_content"
                    android:layout_width="match_parent"
                    android:layout_weight="1"
                    android:orientation="vertical"
                    android:gravity="fill_horizontal">

                    <LinearLayout
                        android:layout_height="wrap_content"
                        android:layout_width="wrap_content"
                        android:orientation="horizontal">

                        <ImageView
                            android:id="@+id/ad_app_icon"
                            android:layout_width="40dp"
                            android:layout_height="40dp"
                            android:adjustViewBounds="true"
                            android:paddingBottom="5dp"
                            android:paddingEnd="5dp"
                            android:paddingRight="5dp"/>

                        <LinearLayout
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:orientation="vertical">

                            <TextView
                                android:id="@+id/ad_headline"
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content"
                                android:textColor="#0000FF"
                                android:text="Join the dark side!"
                                android:textSize="16sp"
                                android:textStyle="bold" />

                            <LinearLayout
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content">

                                <TextView
                                    android:id="@+id/ad_advertiser"
                                    android:layout_width="wrap_content"
                                    android:layout_height="wrap_content"
                                    android:gravity="bottom"
                                    android:textSize="14sp"
                                    android:text="Google"
                                    android:textColor="#222222"
                                    android:textStyle="bold"/>

                                <RatingBar
                                    android:id="@+id/ad_stars"
                                    style="?android:attr/ratingBarStyleSmall"
                                    android:layout_width="wrap_content"
                                    android:layout_height="wrap_content"
                                    android:isIndicator="true"
                                    android:numStars="5"
                                    android:stepSize="0.5"
                                    android:rating="4" />
                            </LinearLayout>

                        </LinearLayout>
                    </LinearLayout>

                    <TextView
                        android:textColor="#555555"
                        android:id="@+id/ad_body"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nis."
                        android:textSize="12sp" />
                </LinearLayout>

                <LinearLayout
                    android:layout_height="wrap_content"
                    android:layout_width="wrap_content"
                    android:orientation="vertical"
                    android:layout_gravity="center_vertical"
                    android:paddingLeft="5dp">

                    <TextView
                        android:id="@+id/ad_store"
                        android:text="Google Play"
                        android:textColor="#222222"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_gravity="center_horizontal"
                        android:textSize="12sp" />

                    <Button
                        android:id="@+id/ad_call_to_action"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:gravity="center"
                        android:layout_margin="0dp"
                        android:text="INSTALL"
                        android:textSize="12sp" />

                    <TextView
                        android:id="@+id/ad_price"
                        android:text="$ 3.49"
                        android:textColor="#222222"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_gravity="center_horizontal"
                        android:textSize="12sp" />

                </LinearLayout>
            </LinearLayout>
        </LinearLayout>
    </android.support.v7.widget.CardView>
</com.google.android.gms.ads.formats.UnifiedNativeAdView>
Code language: HTML, XML (xml)

Feel free to modify it however you want, but keep all text/image/media elements in there. Currently, the SDK displays a warning when not elements are configured but in the future this will not be allowed.

Step 3: Add the custom renderer

This custom renderer will initiate the ad request and the inflate the above layout into the actual ad control.

using Android.Content;
using Android.Gms.Ads;
using Android.Gms.Ads.Formats;
using Android.Views;
using Android.Widget;
using MyApp1.Droid.Renderers;
using System;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly: ExportRenderer(typeof(MyApp1.Controls.NativeAdView), typeof(NativeAdViewRenderer))]

namespace MyApp1.Droid.Renderers
{
    public class NativeAdViewRenderer : ViewRenderer
    {
        public NativeAdViewRenderer(Context context) : base(context)
        {

        }

        protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.View> e)
        {
            base.OnElementChanged(e);

            if (Control == null)
            {
                var adLoader = new AdLoader.Builder(Context, "ca-app-pub-3940256099942544/1044960115");

                var listener = new UnifiedNativeAdLoadedListener();
                listener.OnNativeAdLoaded += (s, ad) =>
                {
                    try
                    {
                        var root = new UnifiedNativeAdView(Context);
                        var inflater = (LayoutInflater)Context.GetSystemService(Context.LayoutInflaterService);
                        var adView = (UnifiedNativeAdView)inflater.Inflate(Resource.Layout.ad_unified, root);

                        populateUnifiedNativeAdView(ad, adView);

                        SetNativeControl(adView);
                    }
                    catch
                    {

                    }
                };

                adLoader.ForUnifiedNativeAd(listener);
                var requestBuilder = new AdRequest.Builder();
                adLoader.Build().LoadAd(requestBuilder.Build());
            }
        }

        private void populateUnifiedNativeAdView(UnifiedNativeAd nativeAd, UnifiedNativeAdView adView)
        {
            adView.MediaView = adView.FindViewById<MediaView>(Resource.Id.ad_media);

            // Set other ad assets.
            adView.HeadlineView = adView.FindViewById<TextView>(Resource.Id.ad_headline);
            adView.BodyView = adView.FindViewById<TextView>(Resource.Id.ad_body);
            adView.CallToActionView = adView.FindViewById<TextView>(Resource.Id.ad_call_to_action);
            adView.IconView = adView.FindViewById<ImageView>(Resource.Id.ad_app_icon);
            adView.PriceView = adView.FindViewById<TextView>(Resource.Id.ad_price);
            adView.StarRatingView = adView.FindViewById<RatingBar>(Resource.Id.ad_stars);
            adView.StoreView = adView.FindViewById<TextView>(Resource.Id.ad_store);
            adView.AdvertiserView = adView.FindViewById<TextView>(Resource.Id.ad_advertiser);

            // The headline and mediaContent are guaranteed to be in every UnifiedNativeAd.
            ((TextView)adView.HeadlineView).Text = nativeAd.Headline;

            // These assets aren't guaranteed to be in every UnifiedNativeAd, so it's important to
            // check before trying to display them.
            if (nativeAd.Body == null)
            {
                adView.BodyView.Visibility = ViewStates.Invisible;
            }
            else
            {
                adView.BodyView.Visibility = ViewStates.Visible;
                ((TextView)adView.BodyView).Text = nativeAd.Body;
            }

            if (nativeAd.CallToAction == null)
            {
                adView.CallToActionView.Visibility = ViewStates.Invisible;
            }
            else
            {
                adView.CallToActionView.Visibility = ViewStates.Visible;
                ((Android.Widget.Button)adView.CallToActionView).Text = nativeAd.CallToAction;
            }

            if (nativeAd.Icon == null)
            {
                adView.IconView.Visibility = ViewStates.Gone;
            }
            else
            {
                ((ImageView)adView.IconView).SetImageDrawable(nativeAd.Icon.Drawable);
                adView.IconView.Visibility = ViewStates.Visible;
            }

            if (string.IsNullOrEmpty(nativeAd.Price))
            {
                adView.PriceView.Visibility = ViewStates.Gone;
            }
            else
            {
                adView.PriceView.Visibility = ViewStates.Visible;
                ((TextView)adView.PriceView).Text = nativeAd.Price;
            }

            if (nativeAd.Store == null)
            {
                adView.StoreView.Visibility = ViewStates.Invisible;
            }
            else
            {
                adView.StoreView.Visibility = ViewStates.Visible;
                ((TextView)adView.StoreView).Text = nativeAd.Store;
            }

            if (nativeAd.StarRating == null)
            {
                adView.StarRatingView.Visibility = ViewStates.Invisible;
            }
            else
            {
                ((RatingBar)adView.StarRatingView).Rating = nativeAd.StarRating.FloatValue();
                adView.StarRatingView.Visibility = ViewStates.Visible;
            }

            if (nativeAd.Advertiser == null)
            {
                adView.AdvertiserView.Visibility = ViewStates.Invisible;
            }
            else
            {
                ((TextView)adView.AdvertiserView).Text = nativeAd.Advertiser;
                adView.AdvertiserView.Visibility = ViewStates.Visible;
            }

            // This method tells the Google Mobile Ads SDK that you have finished populating your
            // native ad view with this native ad.
            adView.SetNativeAd(nativeAd);
        }
    }

    public class UnifiedNativeAdLoadedListener : AdListener, UnifiedNativeAd.IOnUnifiedNativeAdLoadedListener
    {
        public void OnUnifiedNativeAdLoaded(UnifiedNativeAd ad)
        {
            OnNativeAdLoaded?.Invoke(this, ad);
        }

        public EventHandler<UnifiedNativeAd> OnNativeAdLoaded { get; set; }
    }
}
Code language: C# (cs)

Make sure to change the namespaces and to update the ad ID. For testing purposes you can use these sample ad IDs provided by Google:

• Native Advanced: ca-app-pub-3940256099942544/2247696110
• Native Advanced Video: ca-app-pub-3940256099942544/1044960115

Step 4: Display the ad in your page

Anywhere in your XAML just add:

<controls:NativeAdView HeightRequest="360" />
Code language: HTML, XML (xml)

Alternatively, if you want to use it in a ListView for example, create a new AdPlaceholder class and insert it in your list every 5th element for example. Then using a data template selector select either your actual list item or the ad view like so:

public class MyDataTemplateSelector : DataTemplateSelector
    {
        private readonly DataTemplate _itemDataTemplate;
        private readonly DataTemplate _adDataTemplate;

        private DataTemplate _selectedDataTemplate;

        public MyDataTemplateSelector()
        {
            _itemDataTemplate= new DataTemplate(typeof(MyItemView));
            _adDataTemplate = new DataTemplate(typeof(NativeAdView));
        }

        protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
        {
            if (item is AdPlaceholder)
            {
                return _adDataTemplate;
            }

            return _itemDataTemplate;
        }
    }
Code language: C# (cs)

Now just don’t forget to attach the data template selector to your ListView.

That’s it. I haven’t got the chance to work on the iOS renderer yet and it will be a few weeks until I get around to it, so if anyone does it just leave it in the comments.

Hope it helps & if you have questions leave them in the comments!