Question

在我的应用程序中，我尝试使用简单的Adapters和FirebaseListAdapter使用简单查询获取listview中的数据，但是所选的数据未在listview中显示，您可以在onCreateview的注释中找到FirebaseAdapter，Code is如下图所示：

package mainproject.mainroject.story;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;

import java.util.ArrayList;

import mainproject.mainroject.story.dummy.DummyContent.DummyItem;

/**
 * A fragment representing a list of Items.
 * <p/>
 * Activities containing this fragment MUST implement the {@link OnListFragmentInteractionListener}
 * interface.
 */
public class ItemFragment extends Fragment {

    // TODO: Customize parameter argument names
    private static final String ARG_COLUMN_COUNT = "column-count";
    // TODO: Customize parameters
    private int mColumnCount = 1;
    private ArrayList<String> musername = new ArrayList<>();
    private OnListFragmentInteractionListener mListener;

    /**
     * Mandatory empty constructor for the fragment manager to instantiate the
     * fragment (e.g. upon screen orientation changes).
     */
    public ItemFragment() {
    }


    // TODO: Customize parameter initialization
    @SuppressWarnings("unused")
    public static ItemFragment newInstance(int columnCount) {
        ItemFragment fragment = new ItemFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_COLUMN_COUNT, columnCount);
        fragment.setArguments(args);
        return fragment;
    }

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

        if (getArguments() != null) {
            mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        final View view = inflater.inflate(R.layout.fragment_item_list, container, false);
        ListView recyclerView = (ListView) view.findViewById(R.id.list);

//        // Set the adapter
//        if (view instanceof RecyclerView) {
//            Context context = view.getContext();
//            if (mColumnCount <= 1) {
//                recyclerView.setLayoutManager(new LinearLayoutManager(context));
//            } else {
//                recyclerView.setLayoutManager(new GridLayoutManager(context, mColumnCount));
//            }
//            recyclerView.setAdapter(new MyItemRecyclerViewAdapter(DummyContent.ITEMS, mListener));
////        }

        FirebaseDatabase mydatabase=FirebaseDatabase.getInstance();
        DatabaseReference myRef = mydatabase.getReference().child("UserDetail");
                Query query=FirebaseDatabase.getInstance().getReference().child("StoriesDetails").orderByChild("story_content").equalTo("story_content");

//The error said the constructor expected FirebaseListOptions - here you create them:
//        FirebaseListOptions<String> options = new FirebaseListOptions.Builder<String>()
//                .setQuery(query, String.class)
//                .setLayout(android.R.layout.simple_list_item_1)
//                .setLifecycleOwner(this)
//                .build();
//        FirebaseListAdapter<String> firebaseListAdapter = new FirebaseListAdapter<String>(options) {
//            @Override
//            protected void populateView(View v, String  model, int position) {
//                TextView text = (TextView)view.findViewById(R.id.id);
//                text.setText(model);
//            }
//        };
        musername.add(String.valueOf(query));
        final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getContext(),android.R.layout.simple_list_item_1, musername);
        recyclerView.setAdapter(arrayAdapter);

//        myRef.addChildEventListener(new ChildEventListener() {
//            @Override
//            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
//                GenericTypeIndicator<Map<String, String>> genericTypeIndicator = new GenericTypeIndicator<Map<String, String>>() {};
//                Map<String,String> map=dataSnapshot.getValue(genericTypeIndicator);
//                String value =map.get("Name");
//
////                musername.add(value);
////                arrayAdapter.notifyDataSetChanged();
//            }
//
//            @Override
//            public void onChildChanged(DataSnapshot dataSnapshot, String s) {
//
//            }
//
//            @Override
//            public void onChildRemoved(DataSnapshot dataSnapshot) {
//
//            }
//
//            @Override
//            public void onChildMoved(DataSnapshot dataSnapshot, String s) {
//
//            }
//
//            @Override
//            public void onCancelled(DatabaseError databaseError) {
//
//            }
//        });
       return view;
    }

//    @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 OnListFragmentInteractionListener {
        // TODO: Update argument type and name
        void onListFragmentInteraction(DummyItem item);
    }
}

布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/list1"
    android:orientation="vertical">

    <TextView
        android:id="@+id/id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/text_margin"
        android:textAppearance="?attr/textAppearanceListItem" />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<ListView 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/list"
    android:name="mainproject.mainroject.story.ItemFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="16dp"
    android:layout_marginRight="16dp"
    app:layoutManager="LinearLayoutManager"
    tools:context="mainproject.mainroject.story.ItemFragment"
    tools:listitem="@layout/fragment_item" />

Answer 1

从代码下面的firebase数据库中获取数据...

   Query query=FirebaseDatabase.getInstance().getReference().child("StoriesDetails").orderByChild("story_content").equalTo("story_content");
    query.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            for (DataSnapshot issue : dataSnapshot.getChildren()) {

                musername.add(issue.getValue(User.class).name); // define your pojo class for getting firebase data.
            }
            final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getContext(),android.R.layout.simple_list_item_1, musername);
            recyclerView.setAdapter(arrayAdapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}

Firebase查询不会在适配器中显示数据

1 个答案: