Ошибка: (72, 42) ошибка: несовместимые типы: FragmentActivity не может быть преобразован в фрагментировать

Question

Я имею около того проблем с моим проектом, я получаю сообщение об ошибке:

Error:(72, 42) error: incompatible types: FragmentActivity cannot be converted to Fragment.

Может кто-нибудь помочь мне по этим вопросам ?

Это одна из моих фрагментов

public class contact_Fragment extends FragmentActivity { 
    View rootview; 
    @Nullable 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle   savedInstanceState) { 
    rootview = inflater.inflate(R.layout.contact_layout, container, false); 
    return rootview;} 


Button sendEmail; 
EditText msg; 

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



    sendEmail = (Button) findViewById(R.id.sendBtn); 
    sendEmail.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      msg = (EditText) findViewById(R.id.msgTxt); 
      String message = msg.getText().toString(); 
      sendEmail(message); 
     } 
    }); 
} 
protected void sendEmail(String message) { 
    String[] to=new String[]{"samsul1993@hotmail.co.uk"}; 
    String subject =("A message from your app!"); 
    Intent emailIntent = new Intent(Intent.ACTION_SEND); 
    emailIntent.putExtra(Intent.EXTRA_EMAIL, to); 
    emailIntent.putExtra(Intent.EXTRA_SUBJECT, subject); 
    emailIntent.putExtra(Intent.EXTRA_TEXT, message); 
    emailIntent.setType("message/rfc822");//rfc822 email protocol 
    startActivity(Intent.createChooser(emailIntent,"Email")); 


}} 

Это мой MainActivity

public class MainActivity extends ActionBarActivity 
    implements NavigationDrawerFragment.NavigationDrawerCallbacks { 

/** 
* Fragment managing the behaviors, interactions and presentation of the navigation drawer. 
*/ 
private NavigationDrawerFragment mNavigationDrawerFragment; 

/** 
* Used to store the last screen title. For use in {@link #restoreActionBar()}. 
*/ 
private CharSequence mTitle; 

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

    mNavigationDrawerFragment = (NavigationDrawerFragment) 
      getSupportFragmentManager().findFragmentById(R.id.navigation_drawer); 
    mTitle = getTitle(); 

    // Set up the drawer. 
    mNavigationDrawerFragment.setUp(
      R.id.navigation_drawer, 
      (DrawerLayout) findViewById(R.id.drawer_layout)); 
} 

@Override 
public void onNavigationDrawerItemSelected(int position) { 

    FragmentActivity objFragment = null; 

    switch (position){ 
     case 0: 
      objFragment = new home_Fragment(); 
      break; 
     case 1: 
      objFragment = new Reservation_Fragment(); 
      break; 
     case 2: 
      objFragment = new contact_Fragment(); 
      break; 


    } 

    // update the main content by replacing fragments 
    FragmentManager fragmentManager = getSupportFragmentManager(); 
    fragmentManager.beginTransaction() 
      .replace(R.id.container, objFragment) 
      .commit(); 
} 

public void onSectionAttached(int number) { 
    switch (number) { 
     case 1: 
      mTitle = getString(R.string.title_section1); 
      break; 
     case 2: 
      mTitle = getString(R.string.title_section2); 
      break; 
     case 3: 
      mTitle = getString(R.string.title_section3); 
      break; 
    } 
} 

public void restoreActionBar() { 
    ActionBar actionBar = getSupportActionBar(); 
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); 
    actionBar.setDisplayShowTitleEnabled(true); 
    actionBar.setTitle(mTitle); 
} 


@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    if (!mNavigationDrawerFragment.isDrawerOpen()) { 
     // Only show items in the action bar relevant to this screen 
     // if the drawer is not showing. Otherwise, let the drawer 
     // decide what to show in the action bar. 
     getMenuInflater().inflate(R.menu.main, menu); 
     restoreActionBar(); 
     return true; 
    } 
    return super.onCreateOptionsMenu(menu); 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    // Handle action bar item clicks here. The action bar will 
    // automatically handle clicks on the Home/Up button, so long 
    // as you specify a parent activity in AndroidManifest.xml. 
    int id = item.getItemId(); 

    //noinspection SimplifiableIfStatement 
    if (id == R.id.action_settings) { 
     return true; 
    } 

    return super.onOptionsItemSelected(item); 
} 

/** 
* A placeholder fragment containing a simple view. 
*/ 
public static class PlaceholderFragment extends Fragment { 
    /** 
    * The fragment argument representing the section number for this 
    * fragment. 
    */ 
    private static final String ARG_SECTION_NUMBER = "section_number"; 

    /** 
    * Returns a new instance of this fragment for the given section 
    * number. 
    */ 
    public static PlaceholderFragment newInstance(int sectionNumber) { 
     PlaceholderFragment fragment = new PlaceholderFragment(); 
     Bundle args = new Bundle(); 
     args.putInt(ARG_SECTION_NUMBER, sectionNumber); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    public PlaceholderFragment() { 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View rootView = inflater.inflate(R.layout.fragment_main, container, false); 
     return rootView; 
    } 

    @Override 
    public void onAttach(Activity activity) { 
     super.onAttach(activity); 
     ((MainActivity) activity).onSectionAttached(
       getArguments().getInt(ARG_SECTION_NUMBER)); 
    } 
} 

}

ошибка появляется здесь:

FragmentManager fragmentManager = getSupportFragmentManager(); 
fragmentManager.beginTransaction() 
     **.replace(R.id.container, objFragment)** 
     .commit(); 

И наконец, я использую импорт android.support.v4.

Answer 1

objFragment должен быть инициализирован фрагмент, например:

Fragment objFragment = null; 

вместо:

FragmentActivity objFragment = null;