startapp广告不起作用

Question

这是我的代码，它没有oncreate方法，我试图集成它，但我失败了。请帮帮我。你可以在下面的代码中找到，它不包含oncreate method.Im新的编码，我尝试了很多时间来解决这个问题，这对我来说很容易，如果oncreate方法在那里，我可以很容易地集成广告网络。伙计们，有什么办法都能帮到我。谢谢

public class MainFragment extends Fragment {

    public MainFragment() {
        // Required empty public constructor
    }

    private final String TAG = "MainFragment";
    Activity activity;
    AdView bannerAdView;
    boolean isAdLoaded;
    CardView cardVideoToGIF, cardImagesToGIF, cardCaptureImage, cardVideoToAudio, cardVideoCutter, cardGallery;
    LinearLayout linearRow2;

    private String SELECTED_TYPE = Constants.TYPE_GIF;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_main, container, false);
    }

    @Override
    public void onResume() {
        super.onResume();
        if (bannerAdView != null) {
            bannerAdView.resume();
        }
        ((MainActivity) activity).setTitle("");
        ((MainActivity) activity).setDrawerState(true);

        if (!MyApplication.isFFmpegSupports) {
            linearRow2.setVisibility(View.GONE);
        }
    }

    @Override
    public void onPause() {
        if (bannerAdView != null) {
            bannerAdView.pause();
        }
        super.onPause();
    }

    @Override
    public void onDestroy() {
        if (bannerAdView != null) {
            bannerAdView.destroy();
        }
        super.onDestroy();
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        initViews(view);

        cardVideoToGIF.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showPopupMenu(cardVideoToGIF);
                SELECTED_TYPE = Constants.TYPE_GIF;
            }
        });