android - 广告仅在模拟器上，在真实设备上丢失

Question

在我的新应用中，我想使用插页式广告。可以通过增加变量重新启动应用程序。当此变量playcount达到10且游戏结束时，将弹出广告并重置变量。它适用于我的模拟器，但在真实设备上，广告不会弹出，变量也不会重置。

public class GameScreen extends Activity {
    public TextView tv; 
    InterstitialAd mInterstitialAd;
    private AdView mAdView;
    public int playcount;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_game);
        TextView playctv = (TextView) findViewById(R.id.textView);

        mInterstitialAd = new InterstitialAd(this);
        mInterstitialAd.setAdUnitId(getString(R.string.interstitial_full_screen));

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

        mInterstitialAd.loadAd(adRequest);

        SharedPreferences prefsplay = this.getSharedPreferences("myPrefsKey",
                Context.MODE_PRIVATE);
        playcount = prefsplay.getInt("play_number", 0);
        playctv.setText(String.valueOf(playcount));    
    }



    public void restart(View view) {
        Intent intent = new Intent(this, GameScreen.class);
        startActivity(intent);
        playcount++;

        SharedPreferences prefsplay = this
                .getSharedPreferences("myPrefsKey",
                        Context.MODE_PRIVATE);
        prefsplay.edit().putInt("play_number", playcount)
                .apply();

    }


    private void showInterstitial() {
        if (mInterstitialAd.isLoaded()) {
            mInterstitialAd.show();
        }
    }



    private void adView() {
        mAdView = (AdView) findViewById(R.id.adView);
        MobileAds.initialize(getApplicationContext(), getResources().getString(R.string.interstitial_full_screen));
        final AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);
    }



    public void gameover() {
        mCountDownTimer.cancel();
        imageButton1.setVisibility(View.VISIBLE);


        mInterstitialAd.setAdListener(new AdListener() {
            public void onAdLoaded() {
                if(playcount == 10) {
                    mInterstitialAd.show();    
                    playcount = 0;

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