So ändern Sie den Namen in der Aktionsleiste, wenn Sie auf Zurück klicken

Question

Ich versuche, eine App zu erstellen. Ich bekomme keinen Namen in der Aktionsleiste. wenn zur Haupttätigkeit von einem Fragment, das Moment, wo wir gehen zurück zur Haupttätigkeit aber Namen auf der Aktionsleiste zurück zu ändern ist nicht Name des Fragments zeigt, nachdem gehen Haupttätigkeit zu unterstützen folgenden anhand von Code-

public class MainActivity extends FragmentActivity implements OnMapReadyCallback, ConnectionCallbacks, OnConnectionFailedListener,LocationListener{ 
DrawerLayout mDrawerLayout; 
ListView mDrawerList; 
@SuppressWarnings("deprecation") 
ActionBarDrawerToggle mDrawerToggle; 
String mTitle=""; 
private final String TAG = this.getClass().getSimpleName(); 

    LocationRequest mLocationRequest; 
    GoogleApiClient mGoogleApiClient; 

    LatLng latLng; 
    GoogleMap mMap; 
    SupportMapFragment mFragment; 
    Marker CurrentMarker,NearbyPlace,FindMarker; 
    EditText editplace = null; 
    Button findbtn = null; 
    boolean firstRun = true; 
    private Boolean exit = false; 


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

    //for connectivity service 
    ConnectivityManager cManager = (ConnectivityManager) getSystemService(this.CONNECTIVITY_SERVICE); 
    NetworkInfo nInfo = cManager.getActiveNetworkInfo(); 
    if (nInfo != null && nInfo.isConnected()) { 
     Toast.makeText(this, "Network is available ", Toast.LENGTH_SHORT).show(); 

     AdView adView = (AdView)findViewById(R.id.adView); 
     AdRequest adRequest = new AdRequest.Builder() 
     //.addTestDevice("abc") 
     .build(); 
     adView.loadAd(adRequest); 
    mFragment=(SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map); 
    mFragment.getMapAsync(this); 

    } 


    else{ 
     Toast.makeText(this, "Network is not available ", Toast.LENGTH_SHORT).show(); 
     Fragment newFragment; 
     FragmentTransaction transaction = getFragmentManager().beginTransaction(); 
     newFragment = new NetworkCheck(); 
     transaction.replace(R.id.content_frame, newFragment); 
     transaction.addToBackStack(null); 
     transaction.commit(); 
    } 

    editplace = (EditText) findViewById(R.id.editplace); 
    findbtn = (Button) findViewById(R.id.findbtn); 

    setListnerOnWidget(); 

    mTitle = (String) getTitle(); 
    // Getting reference to the DrawerLayout 
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
    mDrawerList = (ListView) findViewById(R.id.drawer_list); 

    // Getting reference to the ActionBarDrawerToggle 
    mDrawerToggle = new ActionBarDrawerToggle(this, 
     mDrawerLayout, 
     R.drawable.ic_drawer, 
     R.string.drawer_open, 
     R.string.drawer_close){ 

      /** Called when drawer is closed */ 
      public void onDrawerClosed(View view) { 
       getActionBar().setTitle(mTitle); 
       invalidateOptionsMenu(); 
      } 

      /** Called when a drawer is opened */ 
      public void onDrawerOpened(View drawerView) { 
       getActionBar().setTitle("Select a menu"); 
       invalidateOptionsMenu(); 
      } 
    }; 

    // Setting DrawerToggle on DrawerLayout 
    mDrawerLayout.setDrawerListener(mDrawerToggle); 
    mDrawerToggle.setDrawerIndicatorEnabled(true); 

    // Creating an ArrayAdapter to add items to the listview mDrawerList 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(
     getBaseContext(), 
     R.layout.drawer_list_item , 
     getResources().getStringArray(R.array.menu) 
    ); 

    mDrawerList.setAdapter(adapter); 

    getActionBar().setHomeButtonEnabled(true); 
    getActionBar().setDisplayHomeAsUpEnabled(true); 


    // Setting item click listener for the listview mDrawerList 
    mDrawerList.setOnItemClickListener(new OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> parent, 
      View view, 
      int position, 
      long id) { 
      displayView(position); 
      // Updating the action bar title 
      String[] menu = getResources().getStringArray(R.array.menu); 
      mTitle = menu[position]; 

      mDrawerLayout.closeDrawer(mDrawerList); 

     } 

     private void displayView(int position) { 
      // TODO Auto-generated method stub 
      Fragment newFragment; 
      FragmentTransaction transaction = getFragmentManager().beginTransaction(); 
      switch (position) { 
      case 0: 

       newFragment = new Help(); 
       transaction.replace(R.id.content_frame, newFragment); 
       transaction.addToBackStack(null); 
       transaction.commit(); 
       break; 

      case 1: 

       newFragment = new ContactUs(); 
       transaction.replace(R.id.content_frame, newFragment); 
       transaction.addToBackStack(null); 
       transaction.commit(); 
       break; 

       case 2: 
        transaction.addToBackStack(null); 
       try 
       { Intent i = new Intent(Intent.ACTION_SEND); 
        i.setType("text/plain"); 
        i.putExtra(Intent.EXTRA_SUBJECT, "My application name"); 
        String sAux = "\nLet me recommend you this application\n\n"; 
        sAux = sAux + "https://play.google.com/store/apps/details?id=com.iqwiner\n\n"; 
        i.putExtra(Intent.EXTRA_TEXT, sAux); 
        startActivity(Intent.createChooser(i, "Choose an action")); 

       } 
       catch(Exception e) 
       { //e.toString(); 
       } 
       Log.e(TAG, "share button is clicked"); 
       break; 

       case 3: 
       newFragment = new Suggestion_Address(); 
       transaction.replace(R.id.content_frame, newFragment); 
       transaction.addToBackStack(null); 
       transaction.commit(); 
       Log.e(TAG, "Suggestion Address button is clicked"); 
       break; 

      } 

     } 

    }); 



} 

private void setListnerOnWidget() { 
    // TODO Auto-generated method stub 
    OnClickListener listener = new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 

      String location = editplace.getText().toString(); 
      if(location!=null && !location.equals("")){ 
        new GeocoderTask().execute(location); 

       } 
    } 
    }; 
    findbtn.setOnClickListener(listener); 

} 



@Override 
protected void onPostCreate(Bundle savedInstanceState) { 
    super.onPostCreate(savedInstanceState); 
    mDrawerToggle.syncState(); 
} 


@Override 
public void onConfigurationChanged(Configuration newConfig) { 
    super.onConfigurationChanged(newConfig); 
    mDrawerToggle.onConfigurationChanged(newConfig); 
} 

//for back button 

@Override 
public void onBackPressed() { 

    if (getFragmentManager().getBackStackEntryCount() > 1) { 
     getFragmentManager().popBackStack(); 

    } else { 
     super.onBackPressed(); 
    } 
     } 

Bitte sagen Ich zeige den Namen auf der Aktionsleiste der Hauptaktivität, wenn Sie von einem Fragment zur Hauptaktivität zurückkehren.

Dank

Answer 1

Mit dieser Codezeile in Ihrem Fragment von Ihnen, wo MainActivity

zurück

@Override 
public void onDestroyView() { 
    super.onDestroyView(); 
    (AppCompatActivity) getActivity()).getSupportActionBar().setTitle("You Main Activity Title"); 

} 

oder versuchen, diese

@Override 
public void onDestroyView() { 
    super.onDestroyView(); 
    getActivity().getSupportActionBar().setTitle("You Main Activity Title"); 

} 

Answer 2

Sie können eine Methode in Hauptaktivität welche Einstell-Aktionsleiste Sie in Onresume of Main Activity aufrufen können.

Beispiel Hauptaktivität Methode:

public void setActionBar(CharSequence title) { 
     toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 
     getSupportActionBar().setHomeButtonEnabled(true); 
     getSupportActionBar().setTitle(title); 
     getSupportActionBar().setDisplayHomeAsUpEnabled(true); 
     }