Flutter and AdMob: A blog around monetizing your Flutter app with AdMob.

Introduction

Mobile applications are a great way to earn revenue from your programming skills. There are many ways to earn money apart from the app store revenue. You can add ads to your apps and monetize them.
Google is the biggest player in the online advertisement industry. Recently, Flutter released a package called google_mobile_ads for monetizing the Flutter application.
This plugin currently supports loading and displaying banner, interstitial (full-screen), native ads, and rewarded video ads.
This plugin can also support Google Ad Manager, if you want to load and display ads from Google Ad Manager

Starter Project

The starter project contains a basic layout for showing posts.
You can get the starter project from the below link -
https://github.com/red-star25/google_ad_flutter
Output of the starter project
These Posts are coming from the post.dart file and is displayed with the help of ListView.builder() widget.
Now that we've seen the starter projects, we can now proceed further by integrating ads in the app.

Install Package

Goto pub.dev and copy the latest version of google_mobile_ads package.
https://pub.dev/packages/google_mobile_ads
And then paste it inside pubspec.yaml

dev_dependencies:
  flutter_test:
    sdk: flutter
  google_mobile_ads: ^0.13.4

Create AdMob account

Open admob website and LogIn/SignUp by using your google account.
https://admob.google.com/home/
After signing in into the admob account. You will be redirected to the dashboard. Which will look like this -
Now go to the Apps in the left sidebar and then click “Add Your First App”.
Now you have to choose the Platform on which you want to show ads. The steps for both are the same. I'm choosing Android for this tutorial.
They are also asking if your app has already been listed on the play store or not. If yes then select yes, otherwise select no.
After that, you will be asked to enter the name of your app and whether you want to use user metrics or not. User Metrics is used to understand the user behavior like, how they are interacting, how many daily active users are there for how much time, etc.
- Now that you have successfully added your app. Let's create an Ad Unit

Create Ad Unit

Ad units are containers you place in your apps to show ads to users. Ad units send ad requests to AdMob, then display the ads they receive to fill the request. When you create an ad unit, you assign it an ad format and ad type(s). Ad format describes the way ads will look in your app and where they'll be located.
Head over to the Ad units section in the left panel. And click on the Get Started button in order to create ad units.
Here you will see different types of ad units.
We are going to use Banner, Interstitial, and Rewarded ad units in our app.
First, let's create a Banner ad unit. You have to enter a name for your ad unit. You can also change some advanced settings if necessary.
Now click on the Create ad unit and you'll get the app ID and ad unit ID that you need to place when you are shipping your app in production.

Don't use production app id and unit id while developing apps. Use the test keys provided by the admob. You can get the test ids for Android here and for iOS here
Now that we've created a banner ad unit we can add it inside our flutter application.

Configuration

iOS Configuration :

Update your app's ios/Runner/Info.plist file to add two keys:
A GADApplicationIdentifier key with a string value of your AdMob app ID (identified in the AdMob UI).
A SKAdNetworkItems key with Google's SKAdNetworkIdentifier value of cstr6suwn9.skadnetwork.

<key>GADApplicationIdentifier</key>
<string>ca-app-pub-3940256099942544~1458002511</string>
<key>SKAdNetworkItems</key>
<array>
  <dict>
    <key>SKAdNetworkIdentifier</key>
    <string>cstr6suwn9.skadnetwork</string>
  </dict>
</array>

Android Configuration :

Head over to AndroidManifest.xml file and add the below code under the <application> tag

<meta-data
 android:name="com.google.android.gms.ads.APPLICATION_ID"
 android:value="ca-app-pub-3940256099942544~3347511713"/>

Now head over to app-level build.gradle and update the minSdkVersion to 19 or higher

  defaultConfig {
      applicationId "com.example.google_ad"
      minSdkVersion 19
      targetSdkVersion 30
      versionCode flutterVersionCode.toInteger()
      versionName flutterVersionName
  }

Initialize SDK

Now that all the configuration is done. The next thing to do is to initialize the Android Ad SDK.
To do that, head over to main.dart and add the below code under main function.

void main() {
WidgetsFlutterBinding.ensureInitialized();
MobileAds.instance.initialize();
runApp(const MyApp());
}

Create Ad State Class

To provide AdUnitId for different platforms (Android, iOS) we need a state which gives us that unit id according to platform.
So let's create a file ad_state.dartand add the below code under it.

class AdState {
String get bannerUnitId {
  if (Platform.isAndroid) {
    return "ca-app-pub-3940256099942544/6300978111"; // test unit id
  } else {
    return "ca-app-pub-3940256099942544/2934735716"; // test unit id
  }
}
}

This bannerUnitId getter will provide unitId for specific platform. You have to update this test id with your production unit ids when you deploy your app.

Adding BannerAd to UI

Now let's create a reference of BannerAd and also a boolean which will change its value when the ad initializes.
Open the HomePage.dart and add below code

class _HomePageState extends State<HomePage> {
  late BannerAd _bannerAd;
  final bool _isBottomBannerAdLoaded = false;
....

Now to initialize the _bannerAd override the initstate and add below code inside it.

@override
void initState() {
  super.initState();
  _bottomBannerAd = BannerAd(
    adUnitId: AdState.bannerUnitId,
    size: AdSize.banner,
    listener: BannerAdListener(
      onAdLoaded: (_) {
        setState(() {
          _isBottomBannerAdLoaded = true;
        });
      },
      onAdFailedToLoad: (ad, error) {
        setState(() {
          _isBottomBannerAdLoaded = false;
        });
        ad.dispose();
      },
    ),
    request: const AdRequest(),
  )..load();
}

And also don't forget to dispose the BannerAd instance.
Here the adUnitId gets our banner unit id from the class AdState that we've created earlier.
size property takes the size of the ad. There are different sizes available. For example, fullBanner, largeBanner, leaderborad, etc.
listener will receive notification for the lifecycle of a BannerId. onAdLoaded suggests Ad successfully loaded - display an AdWidget with the banner ad. onAdFailedToLoad suggests Ad failed to load - log the error and dispose the ad.
request is used to request the ad for displaying it in the UI.

Adding AdWidget to UI

Now to add BannerAd to the screen, the package provides us a widget called AdWidget.
We have to pass our _bottomBannerAd to AdWidget constructor

Scaffold(
    bottomNavigationBar: _isBottomBannerAdLoaded
        ? SizedBox(
            height: _bottomBannerAd.size.height.toDouble(),
            width: _bottomBannerAd.size.width.toDouble(),
            child: AdWidget(ad: _bottomBannerAd),
          )
        : Container(),
// .....

Woohoo!! 🎉

Adding InterstialAd to UI

Interstitial ads are full-screen ads that cover the interface of the app.
So, first, create an InterstialAd ad unit from the AdMob console. And then head over to the next step.
Let's now create a getter in AdState file for getting the unitID

static String get interstitialAdUnitId {
  if (Platform.isAndroid) {
    return "ca-app-pub-3940256099942544/8691691433";
  } else {
    return "ca-app-pub-3940256099942544/5135589807";
  }
}

To display Interstitial ads we have to first create an instance and also a boolean which is used to check if the ad is loaded or not.

InterstitialAd? _interstitialAd;
bool _isInterstitialAdLoaded = false;

Now, load the InterstitialAd inside the initstate and also dispose the _interstitialAd inside dispose function.

@override
void initState() {
  super.initState();
  InterstitialAd.load(
    adUnitId: AdState.interstitialAdUnitId,
    request: const AdRequest(),
    adLoadCallback: InterstitialAdLoadCallback(
      onAdLoaded: (InterstitialAd ad) {
        _interstitialAd = ad;
        _isInterstitialAdLoaded = true;
      },
      onAdFailedToLoad: (LoadAdError error) {
        _isInterstitialAdLoaded = false;
        _interstitialAd.dispose();
      },
    ),
  );
}

@override
void dispose() {
  _bottomBannerAd.dispose();
  _interstitialAd.dispose();
  super.dispose();
}

Now let's load this InterstitialAd when the user clicks on any of the posts.
To do that, all you have to do, is to call the show() method on Navigation, Just like below

GestureDetector(
              onTap: () {
                if (_isInterstitialAdLoaded) {  
                  _interstitialAd.show();   // <- here
                }
                Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (_) => PostPage(
                      post: post,
                    ),
                  ),
                );
              },
              child: PostCard(
                hasReadMore: true,
                post: post,
  )
),

Woohoo!! 🎉

Adding RewardedAd to UI

Rewarded ads provide an opportunity for users to watch a video or engage with a playable ad in exchange for a reward within the app.
This is usually used in Games.
So, first, create a Rewarded ad unit from the AdMob console. Here you can also Enter information about the rewards users will receive after viewing a rewarded ad in this ad unit. Define the reward items—such as coins or extra lives—and their amounts.
First, let's create a getter for getting the unitId for rewarded ads

static String get rewardedAdUnitId {
  if (Platform.isAndroid) {
    return "ca-app-pub-3940256099942544/5224354917";
  } else {
    return "ca-app-pub-3940256099942544/1712485313";
  }
}

Now, let's implement it in our app. First, let's create an instance and a boolean as we've done in the above two example

late RewardedAd _rewardedAd;
bool _isRewardedAdLoaded= false;

Let's initialize this inside initState

@override
void initState() {
  super.initState();
  RewardedAd.load(
    adUnitId: AdState.rewardedAdUnitId,
    request: const AdRequest(),
    rewardedAdLoadCallback: RewardedAdLoadCallback(
      onAdLoaded: (ad) {
        _rewardedAd = ad;
        ad.fullScreenContentCallback = FullScreenContentCallback(
          onAdDismissedFullScreenContent: (ad) {
            setState(() {
              _isRewardedAdLoaded = false;
            });
          },
        );
        setState(() {
          _isRewardedAdLoaded = true;
        });
      },
      onAdFailedToLoad: (err) {
        setState(() {
          _isRewardedAdLoaded = false;
        });
      },
    ),
  );
}

Also dispose it inside dispose() function

@override
void dispose() {
  _bottomBannerAd.dispose();
  _interstitialAd.dispose();
  _rewardedAd.dispose();
  super.dispose();
}

Now let's show() this on FloatingActionButton click

Scaffold(
    floatingActionButton: FloatingActionButton(
      child: const Icon(Icons.gamepad),
      onPressed: () {
        _rewardedAd.show(
          onUserEarnedReward: (ad, reward) {
            // perform operation when earned rewards
          },
        );
      },
    ),
//....

Wrapping Up

That's It. It's that simple to integrate ads in your app. But only adding ads is not efficient when it comes to monetizing.
You should also take care of your user experience and not popping ads every single place. There are many strategies that you can use to make your app more user-friendly and also a source of income at the same time.
So, If you found this article helpful then make sure to share it with others. And also leave feedback in the comments.
Thanks for reading. See you in the next article. Till then.....

Flutter and AdMob: A blog around monetizing your Flutter app with AdMob.

Integrate `Banner`, `Interstitial`, and `Rewarded` ads to your flutter application.

Introduction

Starter Project

Install Package

Create AdMob account

Create Ad Unit

Configuration

iOS Configuration :

Android Configuration :

Initialize SDK

Create Ad State Class

Adding BannerAd to UI

Adding AdWidget to UI

Adding InterstialAd to UI

Adding RewardedAd to UI

Wrapping Up

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