添加到活動中但未顯示的片段

Question

我創建了一個活動並嘗試將一個片段插入到活動中，但運行時活動創建時不會顯示該片段。只是一個空白區域，沒有構建錯誤。

感謝您提前提供任何幫助。

MainActivity.java

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

     final HomeFragment homeFragment = new HomeFragment(); 

     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
       this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); 
     drawer.setDrawerListener(toggle); 
     toggle.syncState(); 

     NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); 
     navigationView.setNavigationItemSelectedListener(this); 

     getFragmentManager().beginTransaction() 
       .replace(R.id.main_container, homeFragment).commit(); 
    } 

    @Override 
    public void onBackPressed() { 
     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     if (drawer.isDrawerOpen(GravityCompat.START)) { 
      drawer.closeDrawer(GravityCompat.START); 
     } else { 
      super.onBackPressed(); 
     } 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main_activity_main, menu); 
     return true; 
    } 

    @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; 
     } else if (id == R.id.search_mag_icon){ 
      // Open intent here 
      Intent i = new Intent(getApplicationContext(), SearchActivity.class); 
      startActivity(i); 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    @SuppressWarnings("StatementWithEmptyBody") 
    @Override 
    public boolean onNavigationItemSelected(MenuItem item) { 
     // Handle navigation view item clicks here. 
     int id = item.getItemId(); 

     if (id == R.id.nav_register) { 
      Intent i = new Intent(getApplicationContext(), RegisterActivity.class); 
      startActivity(i); 
     } else if (id == R.id.nav_login) { 
      Intent i = new Intent(getApplicationContext(), LoginActivity.class); 
      startActivity(i); 
     } else if (id == R.id.nav_my_listings) { 
      // navigate to my listings 
     } else if (id == R.id.nav_how) { 
      // navigate to how it works page 
     } else if (id == R.id.nav_help) { 
      // navigate to help page 
     } else if (id == R.id.nav_contact_us) { 
      // navigate to contact page, 
     } 

     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     drawer.closeDrawer(GravityCompat.START); 
     return true; 
    } 
} 

HomeFragment.java

public class HomeFragment extends Fragment { 

    ImageView bookIcon; 
    ImageView barcodeIcon; 
    ImageView messageIcon; 
    ImageView listIcon; 


    public HomeFragment() { 
    } 

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

     setHomeIcons(rootView); 

     return rootView; 
    } 

    public void setHomeIcons(View rootView){ 
     bookIcon = (ImageView)rootView.findViewById(R.id.bookIcon); 
     bookIcon.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       // Launching All products Activity 
       Intent i = new Intent(getActivity().getApplicationContext(), BrowseUniCourseActivity.class); 
       startActivity(i); 
      } 
     }); 

     barcodeIcon = (ImageView)rootView.findViewById(R.id.barcodeIcon); 
     barcodeIcon.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       Snackbar.make(v, "Will open 'Barcode' Intent", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 

     messageIcon = (ImageView)rootView.findViewById(R.id.messageIcon); 
     messageIcon.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       Snackbar.make(v, "Will open 'My Messages' Intent", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 

      } 
     }); 

     listIcon = (ImageView)rootView.findViewById(R.id.listIcon); 
     listIcon.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       Snackbar.make(v, "Will open 'My Listings' Intent", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 
    } 
} 

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.DrawerLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/drawer_layout" 
    android:background="#FFF" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:fitsSystemWindows="true" 
    tools:openDrawer="start"> 

    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:orientation="vertical" > 

     <include 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      layout="@layout/app_bar_main" /> 

     <FrameLayout 
      android:id="@+id/main_container" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" > 
     </FrameLayout> 
    </LinearLayout> 

    <android.support.design.widget.NavigationView 
     android:id="@+id/nav_view" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:layout_gravity="start" 
     android:fitsSystemWindows="true" 
     android:background="@color/colorPrimaryDark" 
     app:itemTextColor="#FFF" 
     app:itemIconTint="#FFF" 
     app:headerLayout="@layout/nav_header_main" 
     app:menu="@menu/activity_main_drawer" /> 

</android.support.v4.widget.DrawerLayout> 

個fragment_home.xml

<?xml version="1.0" encoding="utf-8"?> 
    <RelativeLayout 
     xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"> 

     <!-- Book icon and text --> 
     <ImageView 
      android:id="@+id/bookIcon" 
      android:layout_width="100dip" 
      android:layout_height="100dip" 
      android:layout_marginLeft="50dip" 
      android:layout_marginTop="110dip" 
      android:src="@drawable/book" /> 

     <TextView 
      android:id="@+id/bookLabel" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/bookIcon" 
      android:layout_marginLeft="20dip" 
      android:text="@string/bookLabel" 
      android:textColor="@color/colorAlt" 
      android:textStyle="bold" /> 


     <!-- Barcode icon and text --> 
     <ImageView 
      android:id="@+id/barcodeIcon" 
      android:layout_width="95dip" 
      android:layout_height="95dip" 
      android:layout_marginLeft="260dip" 
      android:layout_marginTop="120dip" 
      android:src="@drawable/barcode" /> 

     <TextView 
      android:id="@+id/barcodeLabel" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/barcodeIcon" 
      android:layout_marginLeft="260dip" 
      android:paddingTop="5dip" 
      android:text="@string/barcodeLabel" 
      android:textColor="@color/colorAlt" 
      android:textStyle="bold" /> 


     <!-- Message icon and text --> 
     <ImageView 
      android:id="@+id/messageIcon" 
      android:layout_width="100dip" 
      android:layout_height="100dip" 
      android:layout_marginLeft="50dip" 
      android:layout_marginTop="350dip" 
      android:src="@drawable/email" /> 

     <TextView 
      android:id="@+id/messageLabel" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/messageIcon" 
      android:layout_marginLeft="55dip" 
      android:text="@string/messageLabel" 
      android:textColor="@color/colorAlt" 
      android:textStyle="bold" /> 

     <!-- List icon and text --> 
     <ImageView 
      android:id="@+id/listIcon" 
      android:layout_width="95dip" 
      android:layout_height="95dip" 
      android:layout_marginLeft="260dip" 
      android:layout_marginTop="350dip" 
      android:src="@drawable/list" /> 

     <TextView 
      android:id="@+id/listLabel" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/listIcon" 
      android:layout_marginLeft="273dip" 
      android:paddingTop="5dip" 
      android:text="@string/listLabel" 
      android:textColor="@color/colorAlt" 
      android:textStyle="bold" /> 

    </RelativeLayout> 

Answer 1

好吧，我想我明白了。將包含移動到您的LinearLayout之外

<include 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     layout="@layout/app_bar_main" /> 


<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 
    <FrameLayout 
     android:id="@+id/main_container" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" > 
    </FrameLayout> 
</LinearLayout>