在Fragment类中扩展Fragment而不是FragmentActivity时出现java片段错误

Question

我有一个主活动页面，根据用户的选择从中调用片段列表。当我在片段类中扩展Fragment时，主活动页面中的replace方法会抛出一个错误，当我在片段页面中扩展fragmentActivity时，需要（此）上下文的方法不起作用。我不确定这方面的工作是什么。如有任何协助/指导，将不胜感激

代码： 主要活动。爪哇

public class MainActivity extends AppCompatActivity {
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


 navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {


        @Override
        public boolean onNavigationItemSelected(MenuItem menuItem) 
       {

            //Check to see which item was being clicked and perform appropriate action

            switch (menuItem.getItemId()){


                case R.id.dance:
                    Toast.makeText(getApplicationContext(),"Dance Selected",Toast.LENGTH_SHORT).show();
                    DANCE fragment_dance = new Dance();
                    FragmentManager fragmentManager = getSupportFragmentManager();
                    FragmentTransaction fragmentTransaction_dance = fragmentManager.beginTransaction();
                    fragmentTransaction_dancce.replace(R.id.frame,fragment_aed);
                    fragmentTransaction_dance.commit();
                    return true;

碎片。爪哇

public class DANCE extends Fragment implements
    GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener
{
    protected synchronized void buildGoogleApiClient() {
    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API).build();


   AdapterAed danceobjects;

    danceobjects= new AdapterDance (this, 0, dancelisting);

}

在fragment类中存在错误，当我让它扩展fragment时引用了“this”，但当它扩展FragmentActivity时，没有错误，但是mainActivity在replace方法中存在错误，无法将该片段识别为片段。谢谢你的时间