Interstitial Ads

Interstitial ads are full-screen ads that cover the interface of their host app. They're typically displayed at natural transition points in the flow of an app, such as between screens. When an app shows an interstitial ad, the user has the choice to either tap on the ad and continue to its destination or close it and return to the app.

Interstitial Ad management in Dart code is handled through the CASInterstitial class, which extends the shared AdScreenInstance class used for all fullscreen ads. The AdScreenInstance class, inherits from the base AdInstance class, which is common for all CAS ad formats. The AdScreenInstance is displayed as an Overlay on top of all app content and is positioned statically; therefore, it cannot be added to the Flutter widget tree.

CAS provides an option to enable autoReload to simplify your app logic. Before using the ad, you should decide whether to enable autoReload, or manually manage each ad loading cycle in your code.

When autoReload is enabled, a new ad will be automatically loaded after each display, and loading failures will trigger automatic retry attempts.

final bool isAutoReloadEnabled = true;

Manual load mode (autoReload: false ) is useful when you only need to show a single ad per app screen, and the screens change frequently.

Below is a diagram showing the ad lifecycle and how autoReload (isAutoload) affects it.

Create Ad instance

The following example creates and loads an interstitial ad:

class AppScreenState extends State<AppScreen> {
  late CASInterstitial _interstitialAd;
  
  @override
  void initState() {
    super.initState();
    
    _interstitialAd = CASInterstitial.createAndLoad( 
      autoReload: isAutoReloadEnabled, 
      onAdLoaded: (AdScreenInstance ad) { 
        // Called when an ad is successfully loaded. 
        print('$ad loaded');  
      },  
      onAdFailedToLoad: (AdInstance ad, AdError error) { 
        // Called when an ad load failed. 
        print('$ad failed to load: ${error.message}.'); 
      }, 
    ); 
  }
}

Ad content may take some time to load after creating an ad instance. To ensure the ad displays instantly when needed, create the ad instance in advance. Use the onAdLoaded callback to be notified when the ad is ready for display.

Ad content callbacks

CASInterstitial has several optional callbacks for the ad lifecycle. These callbacks can be set either as arguments in the createAndLoad() function or later via the properties of the ad instance.

_interstitialAd.onAdFailedToShow = (AdInstance ad, AdError error) { 
  // Called when the ad failed to show full screen content. 
  print('$ad failed to show: ${error.message}.');  
};  
_interstitialAd.onAdShowed = (AdScreenInstance ad) {  
  // Called when the ad showed the full screen content.
  print('$ad showed');  
};  
_interstitialAd.onAdImpression = (AdInstance ad, AdContentInfo contentInfo) { 
  // Called when an impression occurs on the ad. 
  print('$ad impression');  
};  
_interstitialAd.onAdClicked = (AdInstance ad) {  
  // Called when a click is recorded for an ad.
  print('$ad clicked');  
};  
_interstitialAd.onAdDismissed = (AdScreenInstance ad) { 
  // Called when the ad dismissed full screen content. 
  print('$ad dismissed');  
};

Show Ad

Interstitial ads should be displayed during natural pauses in the flow of an app. Between app screens is a good example, or after the user completes a task.

You can choose when to show the ad by calling show():

_interstitialAd.show();

If the ad is not ready at that moment, the onAdFailedToShow callback will be triggered with a reason provided in the AdError.

You have the option to check isLoaded if it's required by your app's logic.

bool isAdLoaded = await _interstitialAd.isLoaded();

Auto Show Ad mode

CAS provides the option to automatically show a loaded ad when the user returns to the app. To enable this behavior, set the autoShow argument to true.

_interstitialAd = CASInterstitial.createAndLoad(
  autoShow: true, 
  ...
)

Release ad resource

Be sure to release ad resources if you’re no longer going to use the ad instance.

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

It may be useful to store the ad instance in static memory for reuse across multiple screens. This way, you don't need to call dispose() and can show the already loaded ad without delay.

Manual reload Ad

When you want to manually control ad loading, use the load() function on the created ad instance to retry loading with the same configuration.

_interstitialAd.load();

Minimum interval between impressions

The minimum interval between showing interstitial ads, in seconds.
Attempting to show a new interstitial ad before the interval has passed after the previous one was dismissed will trigger onAdFailedToShow with AdError.codeNotPassedInterval.

_interstitialAd = CASInterstitial.createAndLoad(
  minInterval: 0, 
  ...
)

Note that the timer for the minimum interval is shared across all interstitial ad instances, but the minimum interval value may differ for each ad instance.

If you need to reset the minimum interval timer after showing a Rewarded Ad or an AppOpen Ad, you can call the _interstitialAd.restartInterval() method in the onAdDismissed callback for these ad formats.

Mute Ad sounds

Indicates if the application’s audio is muted. Affects initial mute state for fullscreen ads. Use this method only if your application has its own volume controls (e.g., custom music or sound effect muting).

CASMobileAds.setAdSoundsMuted(true);

Not muted by default.

Some best practices

Consider whether interstitial ads are the right type of ad for your app.

Interstitial ads work best in apps with natural transition points. The conclusion of a task within an app, like sharing an image or completing a game level, creates such a point. Because the user is expecting a break in the action, it's easy to present an interstitial ad without disrupting their experience. Make sure you consider at which points in your app's workflow you'll display interstitial ads and how the user is likely to respond.

Remember to pause the action when displaying an interstitial ad.

There are a number of different types of interstitial ads: text, image, video, and more. It's important to make sure that when your app displays an interstitial ad, it also suspends its use of some resources to allow the ad to take advantage of them. For example, when you make the call to display an interstitial ad, be sure to pause any audio output being produced by your app.

Allow for adequate loading time.

Just as it's important to make sure you display interstitial ads at an appropriate time, it's also important to make sure the user doesn't have to wait for them to load. Loading the ad in advance by calling load() before you intend to call show() can ensure that your app has a fully loaded interstitial ad at the ready when the time comes to display one.

Don't flood the user with ads.

While increasing the frequency of interstitial ads in your app might seem like a great way to increase revenue, it can also degrade the user experience and lower clickthrough rates. Make sure that users aren't so frequently interrupted that they're no longer able to enjoy the use of your app.

Complete example

• Interstitial ad example