タブ付きフラグメントのみ最初のフラグメントを表示する

Question

以下のクラスで概要を説明したタブ付きフラグメントがあります。

友だちとグループの情報のリストが2つあります。私が抱えている問題は、グループのリストが最初に「フレンド」タブ内でレンダリングされ、次に「フレンド」リストが「フレンド」タブ内でレンダリングできるように消えることです。ただし、[グループ]タブにスワイプすると、グループリストはレンダリングされません。

どうすれば解決できますか？

タブ付きの活動：

public class InvitingFriendsGroupsToEvents extends AppCompatActivity { 

    /** 
    * The {@link android.support.v4.view.PagerAdapter} that will provide 
    * fragments for each of the sections. We use a 
    * {@link FragmentPagerAdapter} derivative, which will keep every 
    * loaded fragment in memory. If this becomes too memory intensive, it 
    * may be best to switch to a 
    * {@link android.support.v4.app.FragmentStatePagerAdapter}. 
    */ 
    private SectionsPagerAdapter mSectionsPagerAdapter; 

    /** 
    * The {@link ViewPager} that will host the section contents. 
    */ 
    private ViewPager mViewPager; 

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

     // Create the adapter that will return a fragment for each of the three 
     // primary sections of the activity. 
     mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 

     // Set up the ViewPager with the sections adapter. 
     mViewPager = (ViewPager) findViewById(R.id.container); 
     mViewPager.setAdapter(mSectionsPagerAdapter); 

     TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); 
     tabLayout.setupWithViewPager(mViewPager); 

    } 

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

     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"; 

     public PlaceholderFragment() { 
     } 

     /** 
     * 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; 
     } 

     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, 
           Bundle savedInstanceState) { 
      View rootView = inflater.inflate(R.layout.fragment_inviting_friends_groups_to_events, container, false); 
      TextView textView = (TextView) rootView.findViewById(R.id.section_label); 
      textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER))); 
      return rootView; 
     } 
    } 

    /** 
    * A {@link FragmentPagerAdapter} that returns a fragment corresponding to 
    * one of the sections/tabs/pages. 
    */ 
    public class SectionsPagerAdapter extends FragmentPagerAdapter { 

     public SectionsPagerAdapter(FragmentManager fm) { 
      super(fm); 
     } 

     @Override 
     public int getCount() { 
      return 2; 
     } 

     @Override 
     public Fragment getItem(int position) { 

      // Need to build 
      // Order/first appearing will be specific to time of day, ie. if in morning, then breakfast/brunch, if midday then lunch, late then dinner 
      switch (position) { 
       case 0: 
        return new InviteFriendsToEventsFragment(); 
       case 1: 
        return new InviteGroupsToEventsFragment(); 
      } 

      return null; 
     } 

     @Override 
     public CharSequence getPageTitle(int position) { 
      switch (position) { 
       case 0: 
        return "Friends"; 
       case 1: 
        return "Groups"; 
      } 
      return null; 
     } 
    } 
} 

フレンドタブ：

public class InviteFriendsToEventsFragment extends Fragment { 
    // ie. once a fiend is invited, it will show their group on the second tab, the name, who invite them 

    MyCustomAdapter dataAdapter = null; 
    SaveSharedPreference preference = new SaveSharedPreference(); 

    final Firebase myFeastFirebase = new Firebase(Constants.getFirebaseUrl()); 
    Firebase presentEventMembers; 
    Firebase myFriends; 
    Firebase sentFriendEventInvites; // this will be the grayed out standing invitation 

    Firebase eventMemberInviteNeedSync; 

    ValueEventListener getFriendsListener; 
    ValueEventListener getEventMembersListener; 
    ValueEventListener getAlreadyInvitedFriendsListener; 

    String eventID; 
    String eventName; 

    ArrayList<Member> mEventMembers = new ArrayList<>(); 
    ArrayList<Member> mFriends = new ArrayList<>(); 
    ArrayList<Member> mAlreadyInvited = new ArrayList<>(); 
    ArrayList<FriendInvite> mFriendsFinalInviteStatuses = new ArrayList<>(); 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
    } 

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     View view = inflater.inflate(R.layout.invite_friends_to_events, container, false); 

     Bundle extras = getActivity().getIntent().getExtras(); 
     eventID = extras.getString("eventID"); 
     eventName = extras.getString("eventName"); 
     Log.v("InvitingFriendsToEvents", "Event ID: " + eventID); 
     Log.v("InvitingFriendsToEvents", "Event Name" + eventName); 

     //Generate list View from ArrayList 
     // Get present group members 
     presentEventMembers = myFeastFirebase.child("eventMembers").child(eventID); 
     myFriends = myFeastFirebase.child("friends").child(preference.getUserSyncID(getContext())); 
     sentFriendEventInvites = myFeastFirebase.child("userEventMemberInviteSent").child(preference.getUserSyncID(getContext())).child(eventID); 

     eventMemberInviteNeedSync = myFeastFirebase.child("eventMemberInviteNeedSync"); 

     getAlreadyInvitedFriendsListener = new ValueEventListener() { 
      @Override 
      public void onDataChange(DataSnapshot dataSnapshot) { 
       for (DataSnapshot inviteSnapshot : dataSnapshot.getChildren()) { 

        Member invitedFriend = new Member(); 
        invitedFriend.setUserUID(inviteSnapshot.getKey()); 
        invitedFriend.setUserName(inviteSnapshot.getValue().toString()); 

        mAlreadyInvited.add(invitedFriend); 

        Log.v("InvitingFriendsToEvents", "Invite Sent userName is: " + inviteSnapshot.getValue().toString()); 
        Log.v("InvitingFriendsToEvents", "Invite Sent ID is: " + inviteSnapshot.getKey().toString()); 

       } 

       // Here will be the operation to get the proper setting for 
       // First: remove from friends, those already in the group: 
       mFriends.removeAll(mEventMembers); 

       // Then add to the invite group 
       for (Member friend : mFriends) { 
        FriendInvite groupMemberInvite = new FriendInvite(); 
        groupMemberInvite.setUserName(friend.getUserName()); 
        groupMemberInvite.setUserUID(friend.getUserUID()); 

        if (mAlreadyInvited.contains(friend)) { 
         groupMemberInvite.setInvitedAlready(true); 
        } 
        mFriendsFinalInviteStatuses.add(groupMemberInvite); 

        Log.v("InvitingFriendsToEvents", "Final List UserName is: " + groupMemberInvite.getUserName()); 
        Log.v("InvitingFriendsToEvents", "Final List UserID is: " + groupMemberInvite.getUserUID()); 
        Log.v("InvitingFriendsToEvents", "Final List InviteStatus is: " + groupMemberInvite.isInvitedAlready()); 
       } 
       //dataAdapter.notifyDataSetChanged(); 

       //create an ArrayAdaptar from the String Array 
       dataAdapter = new MyCustomAdapter(getActivity(), 
         R.layout.country_info, mFriendsFinalInviteStatuses); 
       ListView listView = (ListView) getActivity().findViewById(R.id.listView1); 
       // Assign adapter to ListView 
       listView.setAdapter(dataAdapter); 

       dataAdapter.notifyDataSetChanged(); 
      } 

      @Override 
      public void onCancelled(FirebaseError firebaseError) { 

      } 
     }; 

     getFriendsListener = new ValueEventListener() { 
      @Override 
      public void onDataChange(DataSnapshot dataSnapshot) { 
       for (DataSnapshot friendSnapshot : dataSnapshot.getChildren()) { 

        if (!friendSnapshot.getKey().equals(preference.getUserSyncID(getContext()))) { 
         Member friend = new Member(); 
         friend.setUserUID(friendSnapshot.getKey()); 
         friend.setUserName(friendSnapshot.child("userName").getValue().toString()); 

         mFriends.add(friend); 

         Log.v("InvitingFriendsToEvents", "Friend userName is: " + friendSnapshot.child("userName").getValue().toString()); 
         Log.v("InvitingFriendsToEvents", "Friend user ID is: " + friendSnapshot.getKey().toString()); 
        } 
       } 

       // after getting friends 
       sentFriendEventInvites.addListenerForSingleValueEvent(getAlreadyInvitedFriendsListener); 
      } 

      @Override 
      public void onCancelled(FirebaseError firebaseError) { 
       Log.v("InvitingFriendsToEvents", "Firebase Error: " + firebaseError.toString()); 

      } 
     }; 

     getEventMembersListener = new ValueEventListener() { 
      @Override 
      public void onDataChange(DataSnapshot dataSnapshot) { 
       for (DataSnapshot groupMemberSnapshot : dataSnapshot.getChildren()) { 

        if (!groupMemberSnapshot.getKey().equals(preference.getUserSyncID(getContext()))) { 
         Member groupMember = new Member(); 
         groupMember.setUserUID(groupMemberSnapshot.getKey()); 
         groupMember.setUserName(groupMemberSnapshot.getValue().toString()); 

         mEventMembers.add(groupMember); 

         Log.v("InvitingFriendsToEvents", "Group member userName is: " + groupMemberSnapshot.getValue().toString()); 
         Log.v("InvitingFriendsToEvents", "Group member user ID is: " + groupMemberSnapshot.getKey().toString()); 
        } 
       } 

//     upon completion of getting groups 
       myFriends.addListenerForSingleValueEvent(getFriendsListener); 

      } 

      @Override 
      public void onCancelled(FirebaseError firebaseError) { 
       Log.v("InvitingFriendsToEvents", "Firebase Error: " + firebaseError.toString()); 

      } 
     }; 
     presentEventMembers.addListenerForSingleValueEvent(getEventMembersListener); 

     //confirmFriendInvites(); 

     return view; 
    } 

    private class MyCustomAdapter extends ArrayAdapter<FriendInvite> { 

     private ArrayList<FriendInvite> groupMemberInviteList; 

     public MyCustomAdapter(Context context, int textViewResourceId, 
           ArrayList<FriendInvite> groupMemberInviteList) { 
      super(context, textViewResourceId, groupMemberInviteList); 
      this.groupMemberInviteList = new ArrayList<>(); 
      this.groupMemberInviteList.addAll(groupMemberInviteList); 
     } 

     private class ViewHolder { 
      TextView inviteSent; 
      CheckBox checkBox; 
     } 

     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 

      ViewHolder holder = null; 
      Log.v("ConvertView", String.valueOf(position)); 

      if (convertView == null) { 
       LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
         Context.LAYOUT_INFLATER_SERVICE); 
       convertView = vi.inflate(R.layout.country_info, null); 

       holder = new ViewHolder(); 
       holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBox1); // here it is 
       holder.inviteSent = (TextView) convertView.findViewById(R.id.invite_already_sent); 

       convertView.setTag(holder); 

       holder.checkBox.setOnClickListener(new View.OnClickListener() { 
        public void onClick(View v) { 
         CheckBox cb = (CheckBox) v; 
         FriendInvite groupMemberInivited = (FriendInvite) cb.getTag(); 
         Toast.makeText(getActivity(), 
           "Clicked on Checkbox: " + cb.getText() + 
             " is " + cb.isChecked(), 
           Toast.LENGTH_LONG).show(); 
         groupMemberInivited.setSelected(cb.isChecked()); 
        } 
       }); 
      } else { 
       holder = (ViewHolder) convertView.getTag(); 
      } 

      FriendInvite groupMemberInvite = groupMemberInviteList.get(position); 

      holder.checkBox.setText(groupMemberInvite.getUserName()); 
      holder.checkBox.setChecked(groupMemberInvite.isSelected()); 
      holder.checkBox.setTag(groupMemberInvite); 

      // Check if already invited, if so, should remove 
      if (groupMemberInvite.isInvitedAlready() == true) { 

       holder.checkBox.setTextColor(Color.GRAY); 
       holder.checkBox.setClickable(false); 

       holder.inviteSent.setText("Invite Already Sent"); 
      } else { 
       holder.inviteSent.setText(""); 
      } 
      return convertView; 
     } 

    } 

} 

グループタブ：

パブリッククラスInviteGroupsToEventsFragmentが断片{// すなわちを拡張します。悪魔が招待されると、それはそれらを招待する2つ目のタブ、名前、上の自分のグループを表示します

GroupInviteCustomAdapter dataAdapter = null; 
SaveSharedPreference preference = new SaveSharedPreference(); 

final Firebase myFeastFirebase = new Firebase(Constants.getFirebaseUrl()); 
Firebase presentEventMembers; 
Firebase sentFriendEventInvites; // this will be the grayed out standing invitation 

Firebase mGroups; 
Firebase mGroupMembers; 

Firebase eventMemberInviteNeedSync; 

ValueEventListener getFriendsListener; 
ValueEventListener getEventMembersListener; 
ValueEventListener getAlreadyInvitedFriendsListener; 
ValueEventListener getUsersGroups; 

String eventID; 
String eventName; 

ArrayList<Member> mEventMembers = new ArrayList<>(); 
ArrayList<Member> mFriends = new ArrayList<>(); 
ArrayList<Member> mAlreadyInvited = new ArrayList<>(); 
ArrayList<FriendInvite> mFriendsFinalInviteStatuses = new ArrayList<>(); 

ArrayList<GroupInvite> mUsersGroups = new ArrayList<>(); 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
} 

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    View view = inflater.inflate(R.layout.invite_groups_to_events, container, false); 

    Bundle extras = getActivity().getIntent().getExtras(); 
    eventID = extras.getString("eventID"); 
    eventName = extras.getString("eventName"); 
    Log.v("InvitingFriendsToEvents", "Event ID: " + eventID); 
    Log.v("InvitingFriendsToEvents", "Event Name" + eventName); 

    //Generate list View from ArrayList 
    // Get present group members 
    presentEventMembers = myFeastFirebase.child("eventMembers").child(eventID); 
    mGroupMembers = myFeastFirebase.child("groupMembers"); // will append: .child("") 
    mGroups = myFeastFirebase.child("usersGroups").child(preference.getUserSyncID(getContext())); 
    sentFriendEventInvites = myFeastFirebase.child("userEventMemberInviteSent").child(preference.getUserSyncID(getContext())).child(eventID); 

    eventMemberInviteNeedSync = myFeastFirebase.child("eventMemberInviteNeedSync"); 

    getUsersGroups = new ValueEventListener() { 
     @Override 
     public void onDataChange(DataSnapshot dataSnapshot) { 
      for (DataSnapshot inviteSnapshot : dataSnapshot.getChildren()) { 

       GroupInvite invitedGroup = new GroupInvite(); 
       invitedGroup.setGroupSyncID(inviteSnapshot.getKey()); 
       invitedGroup.setGroupName(inviteSnapshot.getValue().toString()); 

       mUsersGroups.add(invitedGroup); 

       Log.v("InvitingFriendsToEvents", "Invite Sent userName is: " + inviteSnapshot.getValue().toString()); 
       Log.v("InvitingFriendsToEvents", "Invite Sent ID is: " + inviteSnapshot.getKey().toString()); 

      } 

      dataAdapter = new GroupInviteCustomAdapter(getActivity(), 
        R.layout.event_invites_groups, mUsersGroups); 
      ListView listView = (ListView) getActivity().findViewById(R.id.listView1); 
      // Assign adapter to ListView 
      listView.setAdapter(dataAdapter); 

      dataAdapter.notifyDataSetChanged(); 

     } 

     @Override 
     public void onCancelled(FirebaseError firebaseError) { 

     } 
    }; 


    mGroups.addListenerForSingleValueEvent(getUsersGroups); 


    return view; 
} 

private class GroupInviteCustomAdapter extends ArrayAdapter<GroupInvite> { 

    private ArrayList<GroupInvite> groupInviteList; 

    public GroupInviteCustomAdapter(Context context, int textViewResourceId, 
            ArrayList<GroupInvite> groupInviteList) { 
     super(context, textViewResourceId, groupInviteList); 
     this.groupInviteList = new ArrayList<>(); 
     this.groupInviteList.addAll(groupInviteList); 
    } 

    private class ViewHolder { 
     TextView inviteSent; 
     CheckBox checkBox; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

     ViewHolder holder = null; 
     Log.v("ConvertView", String.valueOf(position)); 

     if (convertView == null) { 
      LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
        Context.LAYOUT_INFLATER_SERVICE); 
      convertView = vi.inflate(R.layout.event_invites_groups, null); 

      holder = new ViewHolder(); 
      holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBox1); // here it is 
      holder.inviteSent = (TextView) convertView.findViewById(R.id.invite_already_sent); 

      convertView.setTag(holder); 

      holder.checkBox.setOnClickListener(new View.OnClickListener() { 
       public void onClick(View v) { 
        CheckBox cb = (CheckBox) v; 
        GroupInvite groupInvited = (GroupInvite) cb.getTag(); 
        Toast.makeText(getActivity(), 
          "Clicked on Checkbox: " + cb.getText() + 
            " is " + cb.isChecked(), 
          Toast.LENGTH_LONG).show(); 
        groupInvited.setSelected(cb.isChecked()); 
       } 
      }); 
     } else { 
      holder = (ViewHolder) convertView.getTag(); 
     } 

     GroupInvite groupInvite = groupInviteList.get(position); 

     holder.checkBox.setText(groupInvite.getName()); 
     holder.checkBox.setChecked(groupInvite.isSelected()); 
     holder.checkBox.setTag(groupInvite); 

     // Check if already invited, if so, should remove 
     if (groupInvite.isInvitedAlready() == true) { 

      holder.checkBox.setTextColor(Color.GRAY); 
      holder.checkBox.setClickable(false); 

      holder.inviteSent.setText("Invite Already Sent"); 
     } else { 
      holder.inviteSent.setText(""); 
     } 
     return convertView; 
    } 

} 

}

Answer 1

移動コード外getUsersGroups =の下にブロック新しいValueEventListener（）

  dataAdapter = new GroupInviteCustomAdapter(getActivity(), 
       R.layout.event_invites_groups, mUsersGroups); 
     ListView listView = (ListView) getActivity().findViewById(R.id.listView1); 
     // Assign adapter to ListView 
     listView.setAdapter(dataAdapter); 

     dataAdapter.notifyDataSetChanged(); 

ValueEventListener（）は、オーバーライドメソッドのみを実行します。私の推測では、上記のコードは決して実行されません。それが動作するかどうか試してみてください。それができない場合、さらにデバッグします。