public class FindPeopleFragment extends Fragment{
public FirebaseAuth.AuthStateListener AuthListener;
DatabaseReference db = FirebaseDatabase.getInstance().getReference();
DatabaseReference leaderListNamesTopLevel = db.child("Names");
ArrayList<String> namesOfLeaders = new ArrayList<>();
ListView lview;
ListAdapter listAdapter;
private static String uid; //uid of the user logged in.
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public FindPeopleFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment FindPeopleFragment.
*/
// TODO: Rename and change types and number of parameters
public static FindPeopleFragment newInstance(String param1, String param2) {
FindPeopleFragment fragment = new FindPeopleFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_find_people, container, false);
lview = (ListView) view.findViewById(R.id.lview);
AuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
uid = user.getUid().toString();
getLeaderNameList(uid);
System.out.println(leaderListNamesTopLevel.child(uid));
} else {
Log.i("Problem:", "couldn't login.");
}
}
};FirebaseAuth.getInstance().addAuthStateListener(AuthListener);
return inflater.inflate(R.layout.fragment_find_people, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
public void getLeaderNameList(String userID){
leaderListNamesTopLevel.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot d: dataSnapshot.getChildren()){
//System.out.println(d.getKey().toString()); //prints the names(keys)/dispnames
namesOfLeaders.add(d.getKey().toString());
System.out.print(namesOfLeaders.toString() + " , ");
System.out.println(+ namesOfLeaders.size());
//Print the items from the ArrayList Then the araylistSize
}
onPost(namesOfLeaders);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
public void onPost(ArrayList<String> leaderList){
listAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, leaderList);
lview.setAdapter(listAdapter);
}
}
主要方法是最后两种方法。
问题是，SysOutPrintLn是完美的，它打印列表，但listview在片段中没有显示任何内容。我该怎么办？
我将列表分配给listview，并且我在OnViewCreate方法中获得了listview，但它仍然没有在listview上显示任何内容。
修改
ACTIVITY_MAIN XML
<?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: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">
<!-- The ActionBar displayed at the top -->
<include
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- The main content view where fragments are loaded -->
<FrameLayout
android:id="@+id/flContent"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</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"
app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
FRAGMENT XML
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="aakarsh.familyshop.FindPeopleFragment">
<!-- TODO: Update blank fragment layout -->
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@android:id/list" />
</FrameLayout>