有关android的问题，求解答

Question

   @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.news_content);        String newsTitle = getIntent().getStringExtra("news_title");        String newsContent = getIntent().getStringExtra("news_content");        NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);        newsContentFragment.refresh(newsTitle, newsContent);    }} NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);这段代码显示     cannot cast 'android.support.v4.app.Fragment' to    'com.example.sweetstar.fragmentbestpractice.NewsContentFragment   错误