插页式激励广告是一种激励用户的广告格式，采用这种格式时，您可以通过在应用中的自然过渡点自动展示的广告向用户提供奖励。与激励广告不同，用户无需自行选择即可观看插页式激励广告。本指南介绍了如何将 Ad Manager插页式激励广告植入到 Flutter 应用中。
前提条件
- Flutter 插件 1.1.0 或更高版本。
- 完成使用入门。您的 Flutter 应用应该已经导入了 Google 移动广告 Flutter 插件。
务必用测试广告进行测试
在构建和测试应用时，请确保使用的是测试广告，而不是实际投放的广告。否则，可能会导致您的帐号被暂停。
对于插页式激励广告，加载测试广告最简便的方法就是使用下面的专用测试广告单元 ID：
/21775744923/example/rewarded_interstitial
测试广告单元配置为为每个请求返回测试广告，您可以在自己应用的编码、测试和调试过程中随意使用这些广告单元。只是一定要在发布应用前用您自己的广告单元 ID 替换这些测试广告单元 ID。
加载广告
以下示例加载了一个插页式激励广告：
class RewardedInterstitialExampleState extends State<RewardedInterstitialExample> {
RewardedInterstitialAd? _rewardeInterstitialdAd;
// TODO: replace this test ad unit with your own ad unit.
final adUnitId = '/21775744923/example/rewarded_interstitial';
/// Loads a rewarded ad.
void loadAd() {
RewardedInterstitialAd.loadWithAdManagerAdRequest(
adUnitId: adUnitId,
adManagerAdRequest: const AdManagerAdRequest(),
adLoadCallback: RewardedInterstitialAdLoadCallback(
// Called when an ad is successfully received.
onAdLoaded: (ad) {
debugPrint('$ad loaded.');
// Keep a reference to the ad so you can show it later.
_rewardedInterstitialAd = ad;
},
// Called when an ad request failed.
onAdFailedToLoad: (LoadAdError error) {
debugPrint('RewardedInterstitialAd failed to load: $error');
},
));
}
}
插页式激励广告事件
通过使用 FullScreenContentCallback，您可以监听各种广告生命周期事件，例如广告展示或关闭的时间。在展示广告之前设置 RewardedInterstitialAd.fullScreenContentCallback，可接收这些事件的通知。以下示例实现了每个方法，并将消息记录到控制台：
class RewardedInterstitialExampleState extends State<RewardedInterstitialExample> {
RewardedInterstitialAd? _rewardedInterstitialAd;
// TODO: replace this test ad unit with your own ad unit.
final adUnitId = '/21775744923/example/rewarded_interstitial';
/// Loads a rewarded ad.
void loadAd() {
RewardedInterstitialAd.loadWithAdManagerAdRequest(
adUnitId: adUnitId,
adManagerAdRequest: const AdManagerAdRequest(),
adLoadCallback: RewardedInterstitialAdLoadCallback(
// Called when an ad is successfully received.
onAdLoaded: (ad) {
ad.fullScreenContentCallback = FullScreenContentCallback(
// Called when the ad showed the full screen content.
onAdShowedFullScreenContent: (ad) {},
// Called when an impression occurs on the ad.
onAdImpression: (ad) {},
// Called when the ad failed to show full screen content.
onAdFailedToShowFullScreenContent: (ad, err) {
// Dispose the ad here to free resources.
ad.dispose();
},
// Called when the ad dismissed full screen content.
onAdDismissedFullScreenContent: (ad) {
// Dispose the ad here to free resources.
ad.dispose();
},
// Called when a click is recorded for an ad.
onAdClicked: (ad) {});
debugPrint('$ad loaded.');
// Keep a reference to the ad so you can show it later.
_rewardedInterstitialAd = ad;
},
// Called when an ad request failed.
onAdFailedToLoad: (LoadAdError error) {
debugprint('RewardedInterstitialAd failed to load: $error');
},
));
}
}
展示广告
RewardedInterstitialAd 以叠加层的形式显示在所有应用内容之上，并且是静态放置的；因此无法将其添加到 Flutter widget 树。您可以通过调用 show() 来选择展示广告的时间。RewardedInterstitialAd.show() 接受 OnUserEarnedRewardCallback，系统会在用户获得奖励时调用它。请务必实现此功能，并奖励观看广告的用户。
_rewardedInterstitialAd.show(onUserEarnedReward: (AdWithoutView ad, RewardItem rewardItem) {
// Reward the user for watching an ad.
});
调用 show() 后，以这种方式显示的 Ad 无法以编程方式移除，并且需要用户输入。一个 RewardedInterstitialAd 只能显示一次。对 show 的后续调用将触发 onAdFailedToShowFullScreenContent。
当不再需要访问广告时，必须处置该广告。调用 dispose() 的最佳做法是在 FullScreenContentCallback.onAdDismissedFullScreenContent 和 FullScreenContentCallback.onAdFailedToShowFullScreenContent 回调中调用。
大功告成！您的应用现在就可以展示插页式激励广告了。