为什么我使用 CustomAdapter 的 ListView 没有被我从 Firebase 检索到 Arraylist 中的数据填充？

Question

我有一个对象数组列表。数据在那里，我试着把它们打印出来。但由于某种原因，我的列表视图仍然无人居住。我想我在这里遗漏了一些明显的东西。请看看并帮助我。提前致谢。这是我调用适配器的代码。

 public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        db= FirebaseDatabase.getInstance().getReference();
        listView = (ListView) getView().findViewById(R.id.listView);
        items.clear();
        myAdapter adapter=new myAdapter(getContext(),retreive());
        listView.setAdapter(adapter);
    }
    public void fetchData(DataSnapshot dataSnapshot){
           try {
               Item i = (Item) dataSnapshot.getValue(Item.class);

               items.add(i);
           } catch (Exception e) {
               Log.v("Error","exception",e);
           }

    }

    public ArrayList<Item> retreive(){

        db.child("Items").addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                fetchData(dataSnapshot);
            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {
                fetchData(dataSnapshot);
            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {
                fetchData(dataSnapshot);
            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {
                fetchData(dataSnapshot);
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                builder.setMessage(databaseError.getMessage())
                        .setTitle("Error!")
                        .setPositiveButton(android.R.string.ok, null);
                AlertDialog dialog = builder.create();
                dialog.show();
            }
        });




        return items;
    }

这是我的适配器：

public class myAdapter extends BaseAdapter {
    private ArrayList<Item> items;
    private Context mContext;


    public myAdapter(Context mContext, ArrayList<Item> items) {
        this.mContext=mContext;
        this.items=items;
    }

    @Override
    public int getCount() {
        return items.size();
    }

    @Override
    public Object getItem(int i) {

        return items.get(i);
    }

    @Override
    public long getItemId(int i) {

        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        Item item=(Item)getItem(i);
        if (view == null) {
            view = LayoutInflater.from(mContext).inflate(R.layout.rowitem, viewGroup, false);
        }
        TextView text1=(TextView)view.findViewById(R.id.text1);
        TextView text2=(TextView)view.findViewById(R.id.text2);
        TextView text3=(TextView)view.findViewById(R.id.text3);
        TextView text4=(TextView)view.findViewById(R.id.text4);
        TextView text5=(TextView)view.findViewById(R.id.text5);
        text1.setText(item.getIdno());
        text2.setText(item.getName());
        text3.setText(item.getBrand());
        text4.setText(item.getCost());
        text5.setText(item.getDate());


        return view;

    }
}

Answer 1

用 firebase UI 列表适配器替换了我的自定义适配器并修复了它。谢谢 everyone.I 在这里发布我的修复程序，以备不时之需。

 db= FirebaseDatabase.getInstance().getReferenceFromUrl("https://stockmanager-142503.firebaseio.com/Items");
        FirebaseListAdapter<Item> firebaseListAdapter = new FirebaseListAdapter<Item>(getActivity(),Item.class,R.layout.rowitem,db) {
            @Override
            protected void populateView(View v, Item item, int position) {
                TextView text1=(TextView)v.findViewById(R.id.text1);
                TextView text2=(TextView)v.findViewById(R.id.text2);
                TextView text3=(TextView)v.findViewById(R.id.text3);
                TextView text4=(TextView)v.findViewById(R.id.text4);
                TextView text5=(TextView)v.findViewById(R.id.text5);
                text1.setText(item.getIdno());
                text2.setText(item.getName());
                text3.setText(item.getBrand());
                text4.setText(item.getCost());
                text5.setText(item.getDate());
            }
        };
        listView = (ListView) getView().findViewById(R.id.listView);
        listView.setAdapter(firebaseListAdapter);

为什么我使用 CustomAdapter 的 ListView 没有被我从 Firebase 检索到 Arraylist 中的数据填充？

Why is my ListView using CustomAdapter not beinmg poplulated by the data I've retrieved from Firebase into an Arraylist?

android

listview

baseadapter

firebase

firebase-realtime-database