Java 从具有fragmenttransaction的活动调用片段

我试图做的是使用

FragmentTransaction

从活动中调用fragment，此时它对我有效，问题是当

活动

调用

片段时，屏幕上会显示这两个片段

活动java代码：

public class ElectricalCalculators extends AppCompatActivity  implements View.OnClickListener {


   Button kwbutton , evbutton ;



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



        findViewById(R.id.menu_back).setOnClickListener(this);
        findViewById(R.id.menu_home).setOnClickListener(this);


        Button kwbutton = (Button) findViewById(R.id.ampsBoutton);
        kwbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent( v.getContext() , AmpsConversion.class);
                startActivityForResult(intent,0);
            }
        });


        Button evbutton = (Button) findViewById(R.id.evBoutton);
        evbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent( v.getContext() , ElectronVoltsConversion.class);
                startActivityForResult(intent,0);
            }
        });


        Button jbutton = (Button) findViewById(R.id.joulesBoutton);
        jbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent( v.getContext() , JoulesConversion.class);
                startActivityForResult(intent,0);
            }
        });


        Button Kwbutton = (Button) findViewById(R.id.kwBoutton);
        Kwbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent( v.getContext() , KwConversion.class);
                startActivityForResult(intent,0);
            }
        });



        Button Kwhbutton = (Button) findViewById(R.id.kwhBoutton);
        Kwhbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent( v.getContext() , KwhConversion.class);
                startActivityForResult(intent,0);
            }
        });




    }

    @Override
    public void onClick(View v) {


        Class clazz = null;

        FragmentManager fragmentManager = getSupportFragmentManager();



        if (v.getId() == R.id.menu_back){

           fragmentManager.beginTransaction().replace(R.id.elctricalCalculator,  new Fragmen2()).commit();



        }


       /** switch (v.getId()) {


            case R.id.menu_back:

                //clazz = Fragmen2.class;
                fragmentManager.beginTransaction().replace(R.id.elctricalCalculator,  new Fragmen2()).commit();


                break;

            case R.id.menu_home:
                clazz = MainActivity.class;
                break;
            /**case R.id.five_tabs_changing_colors:
             clazz = FiveColorChangingTabsActivity.class;
             break;*/

        //}


//        startActivity(new Intent(this, clazz));

    }
}

片段代码：

public class Fragmen2 extends Fragment {

    Button Tboton,
            Lboton,
            Pboton,
            Dboton,
            wboton,
            eboton;



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view =  inflater.inflate(R.layout.fragment_fragmen2, container, false);


        Tboton = (Button)view.findViewById(R.id.boton1fragmen2); /**boton que conecta el fragment 2 con la actividad temperatura */
        Tboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                Intent Tboton = new Intent( getActivity() ,Temperatura.class);
                startActivity(Tboton);
            }
        });

        Lboton =(Button)view.findViewById(R.id.boton2fragmen2); 


      Lboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               Intent Lboton = new Intent(getActivity() , Dimensions.class);
                startActivity(Lboton);

            }
        });

        View v = inflater.inflate(R.layout.fragment_fragmen1, container, false);

        /**Pboton = (Button)view.findViewById(R.id.boton3fragmen2);
        Pboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {




            }


        });*/


        Dboton = (Button)view.findViewById(R.id.boton4fragmen2);
        Dboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent Dboton = new Intent(getActivity(),Dimensions.class);
                startActivity(Dboton);
            }
        });





        wboton = (Button)view.findViewById(R.id.boton3fragmen2);

        wboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent wboton = new Intent(getActivity(),Weight.class);
                startActivity(wboton);
            }
        });



        eboton = (Button)view.findViewById(R.id.boton4fragmen2);

        eboton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent eboton = new Intent(getActivity(),ElectricalCalculators.class);
                startActivity(eboton);
            }
        });



        return  view;





    }






    }

“调用片段”是指“向用户显示
Fragmen2
的实例”？如果要用片段替换活动，则为petey