如果已经加载了一个插页式广告，如何避免加载 Admob 插页式广告？

Question

I am loading Interstitial ad in baseactivity's oncreate method, This baseactivity is extended by all other activities of the app so every time I start a new activity a new interstitial is being loaded even if there's one loaded already.

private InterstitialAd mInterstitialAd;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        createAd();
}

    public void createAd () {

        AdRequest adRequest = new AdRequest.Builder().build();

        InterstitialAd.load(BaseActivity.this, "ca-app-pub-3940256099942544/8691691433", adRequest, new InterstitialAdLoadCallback() {

            @Override
            public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
                Toast.makeText(BaseActivity.this, "Ad Loaded",
                        Toast.LENGTH_LONG).show();
                mInterstitialAd = interstitialAd;
                mInterstitialAd.setFullScreenContentCallback(new FullScreenContentCallback(){
                    @Override
                    public void onAdDismissedFullScreenContent() {
                        // Called when fullscreen content is dismissed.
                        Toast.makeText(BaseActivity.this, "fullscreen content is dismissed.",
                                Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onAdFailedToShowFullScreenContent(AdError adError) {
                        // Called when fullscreen content failed to show.
                        Toast.makeText(BaseActivity.this, "fullscreen content failed to show.",
                                Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onAdShowedFullScreenContent() {
                        // Called when fullscreen content is shown.
                        // Make sure to set your reference to null so you don't
                        // show it a second time.
                        mInterstitialAd = null;
                        Toast.makeText(BaseActivity.this, "fullscreen content is shown.",
                                Toast.LENGTH_LONG).show();
                    }
                });
            }

            @Override
            public void onAdFailedToLoad(@NonNull LoadAdError loadAdError) {
                Toast.makeText(BaseActivity.this, "Ad Failed to Load",
                        Toast.LENGTH_LONG).show();
            }

        });

    }

How to load them only once when base activity created first time?

Answer 1

In you code every activity that extend base activity contains instance of it own of InterstitialAd , if you think that if you created base activity so InterstitialAd will be shared across all your activities you are wrong (read about inheritance).

A quick hack is to make InterstitialAd static , a better approach is to create singleton class or that contain InterstitialAd , or even you can attach InterstitialAd to your application class, that by itself is singe instance.