底部导航视图在片段上。

huangapple
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英文:

BottomNavigationView on fragment

问题

我使用了底部导航视图（Bottom Navigation View），在一个片段（Fragment）上它的工作不正常，问题在于没有过渡效果，只显示了第一个选定的项目。

  1. navigationView.setSelectedItemId(R.id.message_menu_Friend);

我的代码：

  1. public class MessageFragment extends Fragment {
  3.     @Override
  4.     public View onCreateView(LayoutInflater inflater, ViewGroup container,
  5.                              Bundle savedInstanceState) {
  6.         View rootView = inflater.inflate(R.layout.fragment_message, container, false);
  8.         BottomNavigationView navigationView = rootView.findViewById(R.id.top_navigation_bar);
  9.         navigationView.setOnNavigationItemSelectedListener(topNav);
  10.         navigationView.setSelectedItemId(R.id.message_menu_Friend);
  11.         getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M, new FriendFragment()).commit();
  13.         return rootView;
  14.     }
  16.     private BottomNavigationView.OnNavigationItemSelectedListener topNav = new BottomNavigationView.OnNavigationItemSelectedListener() {
  17.         @Override
  18.         public boolean onNavigationItemSelected(@NonNull MenuItem item) {
  19.             Fragment selectedItem = null;
  20.             switch (item.getItemId()) {
  21.                 case R.id.message_menu_message:
  22.                     selectedItem = new MessagesFragment();
  23.                     break;
  24.                 case R.id.message_menu_Friend:
  25.                     selectedItem = new FriendFragment();
  26.                     break;
  27.             }
  28.             assert selectedItem != null;
  29.             getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M, selectedItem).commit();
  30.             return true;
  31.         }
  32.     };
  33. }

XML文件：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:tools="http://schemas.android.com/tools"
  4.     android:layout_width="match_parent"
  5.     android:layout_height="match_parent"
  6.     xmlns:app="http://schemas.android.com/apk/res-auto"
  7.     tools:context=".MessageFragment">
  9.     <androidx.constraintlayout.widget.ConstraintLayout
  10.         android:layout_width="match_parent"
  11.         android:layout_height="match_parent">
  13.         <FrameLayout
  14.             android:layout_marginTop="112dp"
  15.             android:layout_width="match_parent"
  16.             android:layout_height="match_parent"
  17.             android:id="@+id/hostFragment_M">
  19.         </FrameLayout>
  21.         <EditText
  22.             android:id="@+id/editTextTextPersonSearch"
  23.             android:layout_width="match_parent"
  24.             android:layout_height="56dp"
  25.             android:background="@color/White"
  26.             android:backgroundTint="@color/White"
  27.             android:drawableEnd="@drawable/ic_baseline_search_24"
  28.             android:drawablePadding="8dp"
  29.             android:ems="10"
  30.             android:hint="@string/search"
  31.             android:inputType="textPersonName"
  32.             android:paddingStart="15dp"
  33.             android:paddingEnd="15dp"
  34.             app:layout_constraintEnd_toEndOf="parent"
  35.             app:layout_constraintStart_toStartOf="parent"
  36.             app:layout_constraintTop_toTopOf="parent" />
  38.         <com.google.android.material.bottomnavigation.BottomNavigationView
  39.             android:id="@+id/top_navigation_bar"
  40.             android:layout_width="match_parent"
  41.             android:layout_height="wrap_content"
  42.             android:background="@color/White"
  43.             app:layout_constraintEnd_toEndOf="parent"
  44.             app:layout_constraintStart_toStartOf="parent"
  45.             app:layout_constraintTop_toBottomOf="@+id/editTextTextPersonSearch"
  46.             app:menu="@menu/message_menu" />
  47.       </androidx.constraintlayout.widget.ConstraintLayout>
  48. </FrameLayout>

当我点击底部导航时，如何使片段显示出来？

英文:

i use Bottom Navigation View and on a fragment its not work fine the problem is there is no transition its only display the first selected

  1. navigationView.setSelectedItemId(R.id.message_menu_Friend);

my code

public class MessageFragment extends Fragment {

  1. @Override
  2. public View onCreateView(LayoutInflater inflater, ViewGroup container,
  3.                          Bundle savedInstanceState) {
  4.     View rootView =inflater.inflate(R.layout.fragment_message, container, false);
  6.     BottomNavigationView navigationView = rootView.findViewById(R.id.top_navigation_bar);
  7.     navigationView.setOnNavigationItemSelectedListener(topNav);
  8.     navigationView.setSelectedItemId(R.id.message_menu_Friend);
  9.     getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M,new FriendFragment()).commit();
  10.     // Inflate the layout for this fragment
  12.     return inflater.inflate(R.layout.fragment_message, container, false);
  13. }
  16. private BottomNavigationView.OnNavigationItemSelectedListener topNav = new BottomNavigationView.OnNavigationItemSelectedListener() {
  17.     @Override
  18.     public boolean onNavigationItemSelected(@NonNull MenuItem item) {
  19.         Fragment selectedItem = null;
  20.         switch (item.getItemId()) {
  21.             case R.id.message_menu_message:
  22.                 selectedItem = new MessagesFragment();
  23.                 break;
  24.             case R.id.message_menu_Friend:
  25.                 selectedItem = new FriendFragment();
  26.                 break;
  28.         }
  29.         assert selectedItem != null;
  30.         getChildFragmentManager().beginTransaction().replace(R.id.hostFragment_M,selectedItem).commit();
  31.         return  true ;
  32.     }
  33. };}

Xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;FrameLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3. xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  4. android:layout_width=&quot;match_parent&quot;
  5. android:layout_height=&quot;match_parent&quot;
  6. xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  7. tools:context=&quot;.MessageFragment&quot;&gt;
  11. &lt;androidx.constraintlayout.widget.ConstraintLayout
  12. android:layout_width=&quot;match_parent&quot;
  13. android:layout_height=&quot;match_parent&quot;&gt;
  16. &lt;FrameLayout android:layout_marginTop=&quot;112dp&quot;
  17.     android:layout_width=&quot;match_parent&quot;
  18.     android:layout_height=&quot;match_parent&quot;
  19.     android:id=&quot;@+id/hostFragment_M&quot;&gt;
  21. &lt;/FrameLayout&gt;
  23. &lt;EditText
  24.     android:id=&quot;@+id/editTextTextPersonSearch&quot;
  25.     android:layout_width=&quot;match_parent&quot;
  26.     android:layout_height=&quot;56dp&quot;
  27.     android:background=&quot;@color/White&quot;
  28.     android:backgroundTint=&quot;@color/White&quot;
  29.     android:drawableEnd=&quot;@drawable/ic_baseline_search_24&quot;
  30.     android:drawablePadding=&quot;8dp&quot;
  31.     android:ems=&quot;10&quot;
  32.     android:hint=&quot;@string/search&quot;
  33.     android:inputType=&quot;textPersonName&quot;
  34.     android:paddingStart=&quot;15dp&quot;
  35.     android:paddingEnd=&quot;15dp&quot;
  36.     app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  37.     app:layout_constraintStart_toStartOf=&quot;parent&quot;
  38.     app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  40. &lt;com.google.android.material.bottomnavigation.BottomNavigationView
  41.     android:id=&quot;@+id/top_navigation_bar&quot;
  42.     android:layout_width=&quot;match_parent&quot;
  43.     android:layout_height=&quot;wrap_content&quot;
  44.     android:background=&quot;@color/White&quot;
  45.     app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  46.     app:layout_constraintStart_toStartOf=&quot;parent&quot;
  47.     app:layout_constraintTop_toBottomOf=&quot;@+id/editTextTextPersonSearch&quot;
  48.     app:menu=&quot;@menu/message_menu&quot;
  49.     /&gt;
  50.   &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
  51. &lt;/FrameLayout&gt;

how can i make it display the fragment when i click on the bottom navigation

答案1

得分: 1

删除这行代码：navigationView.setSelectedItemId(R.id.message_menu_Friend);，并且将getChildFragmentManager()改为getSupportFragmentManager()。另外，在onCreate方法中，只需返回rootView，而不是重新进行布局填充。

英文:

Remove the line navigationView.setSelectedItemId(R.id.message_menu_Friend);, and also change getChildFragmentManager() to getSupportFragmentManager(). Also, in the onCreate method, just return rootView instead of inflating again.

huangapple
  • 本文由 发表于 2020年8月28日 22:45:09
  • 转载请务必保留本文链接：https://go.coder-hub.com/63636031.html
  • android
  • android-fragments
  • bottomnavigationview
  • java
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