广告预加载（Alpha 版）

广告预加载是一种由 SDK 管理的加载和缓存流程，可消除手动加载和缓存广告的需求。通过此流程，您可以在需要时展示广告，而无需手动加载广告或处理广告加载回调。

本指南介绍了如何配置预加载广告、检查预加载广告的可用性，以及如何获取和展示预加载广告。

前提条件

在继续学习本教程之前，您需要完成以下事项：

  • 安装 Google 移动广告 SDK（Beta 版）0.14.0-alpha01 或更高版本。
  • 通读入门指南。

开始预加载广告

如需开始预加载，请调用 startPreload()。Google 移动广告 SDK 会自动重试预加载配置的失败广告请求。

以下示例开始预加载广告：

Kotlin

private fun startPreloading(adUnitID: String) {
  val adRequest: AdRequest = AdRequest.Builder(adUnitID).build()
  val preloadConfig = PreloadConfiguration(adRequest)
  InterstitialAdPreloader.start(adUnitID, preloadConfig)
}

Java

private void startPreloading(String adUnitId) {
  AdRequest adRequest = new AdRequest.Builder(adUnitId).build();
  PreloadConfiguration preloadConfig = new PreloadConfiguration(adRequest);
  InterstitialAdPreloader.start(adUnitId, preloadConfig);
}

可选：修改预加载广告

如需更改预加载的广告，请调用 destroy()，然后使用修改后的配置再次调用 startPreload()。

可选：停止预加载广告

如需停止预加载广告，请使用预加载 ID 调用 destroy()。

可选：设置缓冲区大小

缓冲区大小用于控制内存中预加载的广告数量。如果您的应用展示广告的速度快于新广告的加载速度，请将缓冲区大小设置为较大的值。如果您担心内存使用情况，请将缓冲区大小设置为较低的值，例如 2。

Kotlin

private fun setBufferSize(adUnitID: String) {
  val adRequest: AdRequest = AdRequest.Builder(adUnitID).build()
  val preloadConfig = PreloadConfiguration(adRequest, bufferSize = 3)
  InterstitialAdPreloader.start(adUnitID, preloadConfig)
}

Java

private void setBufferSize(String adUnitId) {
  AdRequest adRequest = new AdRequest.Builder(adUnitId).build();
  PreloadConfiguration preloadConfig = new PreloadConfiguration(adRequest, 3);
  InterstitialAdPreloader.start(adUnitId, preloadConfig);
}

可选：接收预加载通知

实现 PreloadCallback 以接收广告预加载事件的通知。为了进行调试和日志记录，这些事件会提供一个响应信息对象。

Kotlin

private fun startPreloadingWithCallback(adUnitID: String) {
  val preloadCallback =
    // [Important] Don't call ad preloader start() or pollAd() within the PreloadCallback.
    object : PreloadCallback {
      override fun onAdFailedToPreload(preloadId: String, adError: LoadAdError) {
        Log.i(
          TAG,
          ("Interstitial preload ad $preloadId failed to load with error: ${adError.message}"),
        )
        // [Optional] Get the error response info for additional details.
        // val responseInfo = adError.responseInfo
      }

      override fun onAdsExhausted(preloadId: String) {
        Log.i(TAG, "Interstitial preload ad $preloadId is not available")
      }

      override fun onAdPreloaded(preloadId: String, responseInfo: ResponseInfo) {
        Log.i(TAG, "Interstitial preload ad $preloadId is available")
      }
    }
  val adRequest: AdRequest = AdRequest.Builder(adUnitID).build()
  val preloadConfig = PreloadConfiguration(adRequest)
  InterstitialAdPreloader.start(adUnitID, preloadConfig, preloadCallback)
}

Java

private void startPreloadingWithCallback(String adUnitId) {
  PreloadCallback preloadCallback =
      // [Important] Don't call ad preloader start() or pollAd() within the PreloadCallback.
      new PreloadCallback() {
        @Override
        public void onAdFailedToPreload(String preloadId, LoadAdError adError) {
          Log.e(
              TAG,
              String.format(
                  "Interstitial preload ad %s failed to load with error: %s",
                  preloadId, adError.getMessage()));
          // [Optional] Get the error response info for additional details.
          // ResponseInfo responseInfo = adError.getResponseInfo();
        }

        @Override
        public void onAdsExhausted(String preloadId) {
          Log.i(TAG, "Interstitial preload ad " + preloadId + " is not available");
        }

        @Override
        public void onAdPreloaded(String preloadId, ResponseInfo responseInfo) {
          Log.i(TAG, "Interstitial preload ad " + preloadId + " is available");
        }
      };

  AdRequest adRequest = new AdRequest.Builder(adUnitId).build();
  PreloadConfiguration preloadConfig = new PreloadConfiguration(adRequest);
  InterstitialAdPreloader.start(adUnitId, preloadConfig, preloadCallback);
}

获取并展示预加载的广告

调用 onAdsAvailable() 后，即可展示广告。随着广告的展示和耗尽，系统会不断提供新的广告。获取广告后，监听广告生命周期事件并展示广告。

以下示例展示了预加载的广告：

Kotlin

private fun pollAndShowAd(activity: Activity, adUnitID: String) {
  // Polling returns the next available ad and loads another ad in the background.
  val ad = InterstitialAdPreloader.pollAd(adUnitID)

  // Interact with the ad object as needed.
  ad?.apply {
    Log.d(TAG, "Interstitial ad response info: ${this.getResponseInfo()}")
    this.adEventCallback =
      object : InterstitialAdEventCallback {
        override fun onAdImpression() {
          Log.d(TAG, "Interstitial ad recorded an impression.")
        }

        override fun onAdPaid(value: AdValue) {
          Log.d(TAG, "Interstitial ad onPaidEvent: ${value.valueMicros} ${value.currencyCode}")
        }
      }

    // Show the ad.
    ad.show(activity)
  }
}

Java

private void pollAndShowAd(Activity activity, String adUnitId) {
  // Polling returns the next available ad and loads another ad in the background.
  final InterstitialAd ad = InterstitialAdPreloader.pollAd(adUnitId);

  // Interact with the ad object as needed.
  if (ad != null) {
    Log.d(TAG, "Interstitial ad response info: " + ad.getResponseInfo());
    ad.setAdEventCallback(
        new InterstitialAdEventCallback() {
          @Override
          public void onAdImpression() {
            Log.d(TAG, "Interstitial ad recorded an impression.");
          }

          @Override
          public void onAdPaid(AdValue value) {
            Log.d(
                TAG,
                "Interstitial ad onPaidEvent: "
                    + value.getValueMicros()
                    + " "
                    + value.getCurrencyCode());
          }
        });

    // Show the ad.
    ad.show(activity);
  }
}

可选：检查预加载广告的可用性

如需了解是否有可用的广告，请调用 isAdAvailable：

Kotlin

private fun isAdAvailable(adUnitID: String): Boolean {
  return InterstitialAdPreloader.isAdAvailable(adUnitID)
}

Java

private boolean isAdAvailable(String adUnitId) {
  return InterstitialAdPreloader.isAdAvailable(adUnitId);
}