这是我的主要活动代码。我想在屏幕上看到的每个按钮上实现广告，当点击时会显示州际广告。但它只显示在btn\ U按钮广告。请指导我如何解决这个问题。

public class MainActivity extends AppCompatActivity {
    private InterstitialAd mInterstitialAd;

    private InterstitialAd mInterstitialAd2;

    Button btn_button,btn_button2,btn_button3,btn_button4,btn_button5;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        MobileAds.initialize(this, new OnInitializationCompleteListener() {
            @Override
            public void onInitializationComplete(InitializationStatus initializationStatus) {
            }});

        btn_button=(Button) findViewById(R.id.button);
        btn_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i3=new Intent(MainActivity.this,Button.class);
                startActivity(i3);

            }
        });

        btn_button2=(Button) findViewById(R.id.button);
        btn_button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i2=new Intent(MainActivity.this,Button.class);
                startActivity(i2);

            }
        });
        btn_button3=(Button) findViewById(R.id.button);
        btn_button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i=new Intent(MainActivity.this,Button.class);
                startActivity(i);

            }
        });
        btn_button4=(Button) findViewById(R.id.button);
        btn_button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i4=new Intent(MainActivity.this,Button.class);
                startActivity(i4);

            }
        });
        btn_button5=(Button) findViewById(R.id.button);
        btn_button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i5=new Intent(MainActivity.this,Button.class);
                startActivity(i5);

            }
        });

        mInterstitialAd = new InterstitialAd(this);
        mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");
        mInterstitialAd.loadAd(new AdRequest.Builder().build());

        btn_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
        mInterstitialAd2 = new InterstitialAd(this);
        mInterstitialAd2.setAdUnitId("ca-app-pub-3940256099942544/1033173712");
        mInterstitialAd2.loadAd(new AdRequest.Builder().build());
        btn_button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInterstitialAd2.isLoaded()) {
                    mInterstitialAd2.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
        btn_button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
        btn_button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
        btn_button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", "The interstitial wasn't loaded yet.");
                }
            }
        });
    }
}