#Lecture 001 — What Is AdMob & Project Setup

Your app is free, but servers, stores and your time are not. AdMob is Google's way to earn from a mobile app by showing ads. Before any code, we learn the ad formats, install the plugin and add Google's test app id so nothing real is ever clicked.

Contents

Prerequisites · Connection · Objectives · Lesson · Code Examples · Common Mistakes · Best Practices · Mini Challenge · Practice Questions · Answers · Takeaways

#Prerequisites

• A running Flutter app on Android or iOS (AdMob does not serve ads on web)
• Basic StatefulWidget and Navigator knowledge

#Connection With Previous Lectures

Earlier courses built screens and saved data. This course turns a finished screen into one that earns. We build one demo app with a button for every ad format.

#Learning Objectives

By the end of this lecture you will be able to:

• Explain what AdMob is and how it differs from AdSense
• Name the six ad formats and when to use each
• Add google_mobile_ads and the app id to Android and iOS
• Know why we use Google's test ids while developing

#Lesson

#1. AdMob vs AdSense

Same company, same payments, different products. A Flutter app uses AdMob.

#2. The Six Ad Formats

#3. Test Ads First — Always

Google publishes sample ids that always return a test ad. We use them for the whole course. Never tap your own real ads while developing — AdMob can suspend an account for invalid traffic. Test ads are safe and clearly labelled "Test Ad".

#4. Create the Project and Add the Plugin

flutter create admob_demo
cd admob_demo
flutter pub add google_mobile_ads

#5. Android Setup

In android/app/src/main/AndroidManifest.xml, add the permission above <application>, and the app id inside it:

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name="com.google.android.gms.permission.AD_ID" />

    <application ...>
        <!-- Google's sample AdMob app ID. Replace with your own before release. -->
        <meta-data
            android:name="com.google.android.gms.ads.APPLICATION_ID"
            android:value="ca-app-pub-3940256099942544~3347511713"/>
        ...

The app crashes on start if this meta-data is missing.

#6. iOS Setup

In ios/Runner/Info.plist, inside the first <dict>:

<key>GADApplicationIdentifier</key>
<string>ca-app-pub-3940256099942544~1458002511</string>
<key>NSUserTrackingUsageDescription</key>
<string>This identifier will be used to deliver personalized ads to you.</string>
<key>SKAdNetworkItems</key>
<array>
    <dict>
        <key>SKAdNetworkIdentifier</key>
        <string>cstr6suwn9.skadnetwork</string>
    </dict>
</array>

• GADApplicationIdentifier — the iOS sample app id (Android and iOS use different ids).
• NSUserTrackingUsageDescription — the text of the iOS tracking prompt.
• SKAdNetworkItems — lets Google's ad network attribute installs. Google publishes a longer list for production; the cstr6suwn9 entry is Google's own.

#Code Examples

#Example 1 — Is the Plugin Installed?

Open pubspec.yaml; under dependencies: you should see:

dependencies:
  flutter:
    sdk: flutter
  google_mobile_ads: ^9.1.0

Run flutter pub get, then flutter run. The default counter app should still start — it proves the manifest edit did not break anything. We add real ad code from Lecture 003.

#Common Beginner Mistakes

1. Missing app id on Android — the app closes immediately and the log mentions that the AdMob app id is missing from AndroidManifest.xml. Add the meta-data inside <application>.

2. Using the Android id on iOS — the two platforms have different app ids.

3. Tapping your own real ads — use test ids in development; invalid clicks can get the account suspended.

4. Testing on web — google_mobile_ads does not support web.

#Best Practices

• Keep test ids in the project until the last lecture
• Put the app id in the manifest and Info.plist, never in Dart
• Keep ads out of the first screen a new user sees

#Mini Challenge

Open AndroidManifest.xml and Info.plist and find the two app ids. Which one ends in ~3347511713?

#Practice Questions

1. What is the difference between AdMob and AdSense?
2. Which format starts with a warning and gives a reward?
3. Why do we use test ids?
4. What happens on Android without the app id meta-data?

#Practice Answers

1. AdMob serves ads in mobile apps; AdSense serves ads on websites.
2. Rewarded interstitial.
3. Real ads clicked by the developer count as invalid traffic and can suspend the account.
4. The app crashes at start.

#Key Takeaways

• AdMob = apps, AdSense = websites
• Six formats: banner, interstitial, app open, native, rewarded, rewarded interstitial
• Android and iOS each need an app id and (for iOS) a tracking description
• Use Google's test ids until you are ready to publish