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

Question

I've an arraylist of objects. The data is there,I tried printing them out in a toast. But for some reason my listview remains unpopulated. I think I'm missing something obvious here. Please take a look and help me out. Thanks in advance. Here's my code for invoking the adapter.

 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;
    }

Here is my adapter:

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;

    }
}

http://www.tutorialspoint.com/android/android_list_view.htm please refer this — Anand Savjani, Sep 25 '16 at 09:45
Are you sure you getting value here **dataSnapshot.getValue(Item.class)** ? — Saveen, Sep 25 '16 at 09:46
Yup. I had it printed out as a toast. All my values are right there. — Judy T Raj, Sep 25 '16 at 09:48
At a glance I think the issue could be in your fetchData method. Firebase has a library that automates populating a ListView easily : https://github.com/firebase/firebaseui-android and also checkout best practices on how to turn Firebase JSON into Java objects : http://stackoverflow.com/questions/32108969/why-do-i-get-failed-to-bounce-to-type-when-i-turn-json-from-firebase-into-java — RamithDR, Sep 25 '16 at 17:51

score 0 · Accepted Answer · answered Sep 26 '16 at 17:32

Replaced my custom adapter with the firebase UI List adapter and that fixed it. Thanks everyone.I'm posting my fix here in case anyone needs this.

 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);

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

1 Answers1