必须实现方法doInBackground（params）

Question

我有一个扩展AsyncTask的类，它必须实现doInBackground方法。 我有下面定义的方法，我仍然有一个错误，说类必须实现方法。

public class MyDownloadJsonAsyncTask  extends AsyncTask<Void , String, Bitmap> {

private final WeakReference<RecyclerView_Adapter> adapterReference;
MovieDataJson movieData;

public MyDownloadJsonAsyncTask(RecyclerView_Adapter adapter)
{
    adapterReference = new WeakReference<RecyclerView_Adapter>(adapter);
}


@Override
protected MovieDataJson doInBackground(String... urls)
{
    MovieDataJson threadMovieData = new MovieDataJson();
    for (String url : urls)
    {
        threadMovieData.downloadMovieDataJson(url);
    }
    return threadMovieData;
}

@Override
protected void onPostExecute(MovieDataJson threadMovieData)
{

    movieData.moviesList.clear();
    for(int i=0;i<threadMovieData.getSize();i++)
    {
        movieData.moviesList.add(threadMovieData.moviesList.get(i));
    }
    if(adapterReference!=null)
    {
        final RecyclerView_Adapter adapter= adapterReference.get();
        if(adapter!=null)
            adapter.notifyDataSetChanged();
    }
}

}

并且@Override对于上面的每个方法都表示方法不会覆盖其超类

中的方法