Question

就像标题所说，我有一个带有自定义适配器的ListView，它从firebase数据库获取数据。

这是我的适配器

public class CustomBolichesAdapter extends BaseAdapter {
Context c;
ArrayList<Boliche> boliches;

public CustomBolichesAdapter(ArrayList<Boliche> boliches,Context c) {
    this.c = c;
    this.boliches = boliches;
}

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

@Override
public Object getItem(int position) {
    return boliches.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if (convertView == null){
        convertView = LayoutInflater.from(c).inflate(R.layout.boliches_card_model,parent,false);
    }


    TextView nombreBoliche =(TextView)convertView.findViewById(R.id.boliches_nombreTxt);
    TextView ciudadBoliche = (TextView)convertView.findViewById(R.id.boliches_ciudadTxt);
    ImageView cardImageBoliche = (ImageView)convertView.findViewById(R.id.boliches_card_image);
    final Boliche  boliches = (Boliche)this.getItem(position);
    String url = boliches.getUrlCard();


    nombreBoliche.setText(boliches.getNombre());
    ciudadBoliche.setText(boliches.getCiudad());
    Glide
            .with(c)
            .load(url)
            .into((cardImageBoliche));

    convertView.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {

            openDetailActivity(boliches.getNombre(),boliches.getDescripcion(),boliches.getUrlHeaderBoliches(),boliches.getUrlViernes(),boliches.getUrlSabado());
        }
        });

     return convertView;
}

这是我的活动

public class BolichesFragment extends Fragment {

    DatabaseReference db;
    FirebaseHelper helper;
    CustomBolichesAdapter adapter;
    ListView lv;

    public BolichesFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {


        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.contenido_boliches, container, false);

        //Iniciar ListView
        lv = (ListView) rootView.findViewById(R.id.lv);

        //Iniciar FIREBASE DB
        db = FirebaseDatabase.getInstance().getReference("Boliches");
        helper = new FirebaseHelper(db);


        //ADAPTER
        adapter = new CustomBolichesAdapter(helper.retrieve(),getActivity());
        lv.setAdapter(adapter);


        return rootView;
    }

}

，这是我的firebase助手

public class FirebaseHelper {

    DatabaseReference db;
    ArrayList<Boliche> boliches = new ArrayList<>();


    public FirebaseHelper(DatabaseReference db) {

        this.db = db;
    }


    //IMPLEMENT FETCH DATA AND FILL ARRAYLIST
    private void fetchData(DataSnapshot dataSnapshot)
    {
        boliches.clear();
        for (DataSnapshot ds : dataSnapshot.getChildren())
        {
            Boliche boliche = ds.getValue(Boliche.class);
            boliches.add(boliche);
        }
    }
    //READ BY HOOKING ONTO DATABASE OPERATION CALLBACKS
    public ArrayList<Boliche> retrieve()
    {
        db.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) {
            }
            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {
            }
            @Override
            public void onCancelled(DatabaseError databaseError) {
            }
        });
        return  boliches;
    }
}

我希望有人可以帮助我，因为在控制台中没有错误，我只是不知道在哪里寻找。

Answer 1

adapter.notifyDataSetChanged();

此方法通知对适配器的更改并更新ListView。每次将项目添加到列表时都应该调用它：

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

ListView未在第一次加载，但在重新打开活动后加载

1 个答案: