Question

我正在做一个Android应用程序。我已成功写入Firebase，但是我在从Firebase读取到ListView时遇到问题。如果有人可以协助将数据读回到应用程序中的ListView，如果我只有一个项目尝试并回读它，如果我尝试获取应用程序失败的所有三个项目。我已经包含了数据库的图片，以了解结构和我的代码。

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.FirebaseDatabase;

 import java.util.ArrayList;

 public class Admin_ViewEvent extends AppCompatActivity {

   // private TextView textViewPersons;
private ListView mListView;
private ArrayList<String> mMeetings = new ArrayList<>();
private Firebase mRef;

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

    mRef = new Firebase("https://saica-sgb-77a4f.firebaseio.com/Meetings");
    mListView = (ListView) findViewById(R.id.ListView);
    //textViewPersons = (TextView) findViewById(R.id.textViewPersons);

    final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mMeetings);
    mListView.setAdapter(arrayAdapter);

    mRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot)
        {
            for(DataSnapshot childSnapShot : dataSnapshot.getChildren()) {

                String date = (String) childSnapShot.child("address").getValue();
                String datetime = (String) childSnapShot.child("datetime").getValue();
                String name = (String) childSnapShot.child("name").getValue();

                mMeetings.add(date);
                mMeetings.add(datetime);
                mMeetings.add(name);

            }
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            System.out.println("The read failed: " + firebaseError.getMessage());
        }
    });

 }
}

Answer 1

您可以使用Firebase UI library。

只需添加依赖项：

dependencies {
    // FirebaseUI Database only
    compile 'com.firebaseui:firebase-ui-database:1.0.1'
}

然后定义一个简单的类来映射你的对象：

public class MyObject {

   private String name;
   private String address;
   private String dateTime;

   public MyObject() {
   }
   ....

}

然后使用类似的东西：

mRef = new Firebase("https://saica-sgb-77a4f.firebaseio.com/Meetings");
mListView = (ListView) findViewById(R.id.ListView);
mAdapter = new FirebaseListAdapter<MyObject>(this, MyObject.class, R.layout.myLayout, mRef) {
        @Override
        protected void populateView(View view, MyObject myObj, int position) {
           //Set the value for the views
           ((TextView)view.findViewById(R.id.xxx)).setText(myObj.getName());
           //...
        }
    };
    mListView.setAdapter(mAdapter);

Answer 2

使用ChildEventListener并输入您的代码：
final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String(this,android.R.layout.simple_list_item_1, mMeetings); mListView.setAdapter(arrayAdapter);

在onChildAdded ....内还创建Model类以从firebase获取数据 public class User {public String name; public String date; public String time; //对// DataSnapshot.getValue(User.class) public User() {}public User(String name, String time, String date) {this.name = name; this.time= time;this.date=date;}的调用所需的默认构造函数
谢谢它会帮助你..

Answer 3

我觉得你错过了什么，你应该加上这个

DatabaseReference myRef = FirebaseAuth.getInstance().getReference
.child("Meetings").child(uid);

然后在onDataChange。

String date = (String) childSnapShot.child("address").getValue();
            String datetime = (String) childSnapShot.child("datetime").getValue();
            String name = (String) childSnapShot.child("name").getValue();

            mMeetings.add(date);
            mMeetings.add(datetime);
            mMeetings.add(name);

如何将Firebase数据导入ListView？

3 个答案: