关于使用从firebase android studio检索创建动态列表视图

Question

当我尝试使用ListView从firebase检索数据时，我遇到了无限运行，我不知道该如何解决它。

这是我的java代码

package com.example.atheer.booklyv1;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.google.firebase.database.ChildEventListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.Map;

public class approvedAdmin extends AppCompatActivity implements View.OnClickListener{

    DatabaseReference dref;
    ListView listview;

    ArrayList<String> list=new ArrayList<>();
     ArrayAdapter<String> adapter;

    public approvedAdmin() {
    }

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_approved_admin);
       listview=(ListView)findViewById(R.id.list);
        dref= FirebaseDatabase.getInstance().getReference("client");
       // adapter.notifyDataSetChanged();
        dref.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                String status;
                String name;
                String email;

                Toast.makeText(approvedAdmin.this, "ok", Toast.LENGTH_SHORT).show();
                for(DataSnapshot ds: dataSnapshot.getChildren() ){
                    if (ds.hasChild("Status")){
                        status=ds.child("Status").getValue(String.class);
                        if (status.equalsIgnoreCase("Not approved")){
                            name= ds.child("name").getValue(String.class);
                            list.add(name);
                            adapter= new ArrayAdapter<String>(approvedAdmin.this, android.R.layout.simple_list_item_1, list);
                            listview.setAdapter(adapter);
                        }}
                    }}
            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {
            }
            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {
            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {
            }
            @Override
            public void onCancelled(DatabaseError databaseError) {
            }
        });
        }

    @Override
    public void onClick(View v) {
    }
}

这是我的xml代码

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".approvedAdmin">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:orientation="vertical"
            android:paddingLeft="15dp"
            android:paddingRight="15dp">
         <ListView
                android:id="@android:id/list"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                />
        </LinearLayout>
</android.support.constraint.ConstraintLayout>

Answer 1

您需要从for循环中移出设置适配器代码，如下所示

for(DataSnapshot ds: dataSnapshot.getChildren() ){
    if (ds.hasChild("Status")){
        status=ds.child("Status").getValue(String.class);
        if (status.equalsIgnoreCase("Not approved")){
            name= ds.child("name").getValue(String.class);
            list.add(name);
        }
    }
}

adapter= new ArrayAdapter<String>(approvedAdmin.this, android.R.layout.simple_list_item_1, list);
listview.setAdapter(adapter);

您还需要将listview id从android:id=“@android:id/list”更改为android:id=“@+id/list”