不使用FirebaseListAdapter从ListView上的Firebase获取数据 [英] Not Getting Data From Firebase on ListView With FirebaseListAdapter

问题描述

此代码的问题是列表视图中未显示数据，并且应用程序也未显示任何错误.我正在从其他活动中初始化此模型类，所以请任何人可以给我关于什么是真正的问题的建议.

The Problem with this code is that the data is not showing in listview and the app is also not showing any error. I am initializing this model class from some other activity, so please any one can give me suggestion about what would be the real problem.

public class FireBaseListAdapter extends AppCompatActivity {

    private ListView mlistview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fire_base_list_adapter);

        mlistview = (ListView)findViewById(R.id.firebase_list);

      //  DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference();

        final Query query = getInstance().getReference();

        FirebaseListOptions<Users> options = new FirebaseListOptions.Builder<Users>().setQuery(query,Users.class).setLayout(R.layout.listview_for_firebaselistadapter).build();

        FirebaseListAdapter<Users> firebaseListAdapter = new FirebaseListAdapter<Users>(options) {
            @Override
            protected void populateView(View v, Users model, int position) {
                model = getItem(position);
                TextView textViewname = (TextView)v.findViewById(R.id.listAdapter_nametext);
                TextView textViewplace = (TextView)v.findViewById(R.id.listAdapter_placetext);

                textViewname.setText(model.getName());
                textViewplace.setText(model.getPlace());
            }
        };
        mlistview.setAdapter(firebaseListAdapter);
    }
}

这是我的模型班:

    public class Users {

    private String name;
    private String place;

    public Users() {
    }

    public Users(String name, String place) {
        this.name = name;
        this.place = place;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPlace() {
        return place;
    }

    public void setPlace(String place) {
        this.place = place;
    }
}

这是我的XML，其中包含两个textView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/listAdapter_nametext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Driver Name"
        android:textSize="25sp"/>
    <TextView
        android:id="@+id/listAdapter_placetext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Driver Place"
        android:textSize="25sp"/>

</LinearLayout>

推荐答案

要解决此问题，您需要覆盖onStart()方法并添加以下代码行:

To solve this, you need to override the onStart() method and add the following line of code:

@Override
protected void onStart() {
    super.onStart();
    firebaseListAdapter.startListening();
}

但是首先不要忘记使firebaseListAdapter变量成为全局变量.

But first don't forget to make the firebaseListAdapter variable global.

private FirebaseListAdapter<Users> firebaseListAdapter;

然后删除FirebaseListAdapter<Users>，在其中初始化适配器.

And then just remove FirebaseListAdapter<Users> where you intialize the adapter.

这篇关于不使用FirebaseListAdapter从ListView上的Firebase获取数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！