碎片相互作用

在我的主要活动中,我在布局中添加了两个片段。

public class MainActivity extends AppCompatActivity {

private Collapsebutton_Fragment cbut_frag;
private ColourView_Fragment cvw_frag;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    cbut_frag = new Collapsebutton_Fragment();
    cvw_frag = new ColourView_Fragment();

    //ColourView Fragment ready
    //CollapseButton Fragment ready

    getSupportFragmentManager().beginTransaction()
            .add(R.id.container_mainactivity, cbut_frag)
            .add(R.id.container_mainactivity, cvw_frag)
            .commit();
}
}

public class ColourView_Fragment extends Fragment {

FragmentManager fragmentManager;
ThreeButton_Fragment tbt_fragment;
public ColourView_Fragment(){}

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.colourview_fragment, container, false);

    FrameLayout frameLayout = (FrameLayout)rootView.findViewById(R.id.ColourView);

    frameLayout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getFragmentManager().beginTransaction()
                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
                    .add(R.id.container_mainactivity, tbt_fragment)
                    .commit();
        }
    });

    return rootView;
}

我得到以下错误:

.add(R.id.container_mainactivity, tbt_fragment)

我如何更正?