在Listview故障时显示Arraylist

Question

因此，我有一个应用程序，可让您创建一个Java对象，其中包含有关您服用的药丸的信息（名称，剂量，每天的剂量数和剩余的药丸数）。然后我存储Firebase实时数据库的此信息，然后使用单独的活动从数据库中获取信息并将其存储在数组列表中，该列表要在列表视图中显示。当前问题是列表视图未显示数组列表的所有数据，仅显示最后添加的药丸对象。

用于上传数据的代码：

package com.example.andrew.pilltracker;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import android.widget.Toolbar;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.auth.*;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

public class SecondActvty extends AppCompatActivity {

static String ref = "Advil";
private FirebaseDatabase mFirebaseDatabase;
DatabaseReference mRootRef;
int id = 1;

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.navigation_home:
               Intent intent = new Intent(SecondActvty.this, MainActivityController.class);
               startActivity(intent);
                return true;
            case R.id.navigation_dashboard:

                return true;
            case R.id.navigation_notifications:
               Intent intent1 = new Intent(SecondActvty.this, ThirdActivity.class);
               startActivity(intent1);
                return true;
        }
        return false;
    }
};



@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second_view);

    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

    mFirebaseDatabase = FirebaseDatabase.getInstance();
    mRootRef = mFirebaseDatabase.getReference();


    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //id++;

            EditText pillName = (EditText)findViewById(R.id.pillName);
            EditText pillDose = (EditText)findViewById(R.id.pillDose);
            EditText pillCount = (EditText)findViewById(R.id.pillCount);
            EditText doseDuration = (EditText)findViewById(R.id.doseDuration);

            String name = pillName.getText().toString();
            String dose = pillDose.getText().toString();
            String day = doseDuration.getText().toString();
            String count = pillCount.getText().toString();
            ref = name;


            Pill pill = new Pill();
            pill.setName(name);
            pill.setCount(count);
            pill.setDay(day);
            pill.setDose(dose);


           if(!name.equals("") && !dose.equals("") && !day.equals("") && !count.equals("")) {
                mRootRef.child("pills").child(name).setValue(pill);
                toastMessage("Success!");
                pillName.setText("");
                pillCount.setText("");
                doseDuration.setText("");
                pillDose.setText("");
            }
                else {
               toastMessage("Please fill all fields");
           }
        }
    });
}
private void toastMessage(String message){
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
    }

    public static String getReference(){
        return ref;
    }


}

以及将从Firebase下载数据并在列表视图中显示的类：

package com.example.andrew.pilltracker;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

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;

public class MainActivityController extends AppCompatActivity {

private TextView mTextMessage;

private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mRootRef;
private ArrayList<String> array;
private ListView mListView;
private ArrayAdapter adapter;




private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.navigation_home:
                mTextMessage.setText(R.string.title_home);
                return true;
            case R.id.navigation_dashboard:
                Intent intent = new Intent(MainActivityController.this, SecondActvty.class);
                startActivity(intent);
                return true;
            case R.id.navigation_notifications:
                mTextMessage.setText(R.string.title_notifications);
                return true;
        }
        return false;
    }
};

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

    mListView = (ListView) findViewById(R.id.listview);
    array = new ArrayList<String>();
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, array);


    mFirebaseDatabase = FirebaseDatabase.getInstance();
    mRootRef = mFirebaseDatabase.getReference();

    mTextMessage = (TextView) findViewById(R.id.message);
    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

    mRootRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
           showData(dataSnapshot);
            mListView.setAdapter(adapter);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });



}

private void showData(DataSnapshot dataSnapshot){
    for(DataSnapshot ds : dataSnapshot.getChildren()){


        Pill pInfo = new Pill();

        pInfo.setName(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getName());
        pInfo.setCount(ds.child(SecondActvty.getReference().toString()/*Integer.toString(databaseRef)*/).getValue(Pill.class).getCount());
        pInfo.setDose(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getDose());
        pInfo.setDay(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getDay());

        array.add(pInfo.getName());
        array.add("Number of Pills Left: " + pInfo.getCount());
        array.add("Number of Pills per Dose: " + pInfo.getDose());
        array.add("Number of Doses per Day: " + pInfo.getDay());
    }
}

//Database shit
@Override
protected void onStart(){
    super.onStart();


}

}

数据库结构： Database

Answer 1

我认为问题在于设置适配器。在添加实际值之前，您已经在适配器中提供了数组，并且正在onDataChange()方法中完成它。

这就是为什么仅显示最后一个药丸数据的原因。要解决该问题，请使用以下代码行：

mRootRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
           for(DataSnapshot ds : dataSnapshot.getChildren()){


               Pill pInfo = new Pill();

               pInfo.setName(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getName());
               pInfo.setCount(ds.child(SecondActvty.getReference().toString()/*Integer.toString(databaseRef)*/).getValue(Pill.class).getCount());
               pInfo.setDose(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getDose());
               pInfo.setDay(ds.child(SecondActvty.getReference().toString()).getValue(Pill.class).getDay());

               array.add(pInfo.getName());
               array.add("Number of Pills Left: " + pInfo.getCount());
               array.add("Number of Pills per Dose: " + pInfo.getDose());
               array.add("Number of Doses per Day: " + pInfo.getDay());
           }

        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        } // don't ignore errors, do something for this too

         adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, array);
         mListView.setAdapter(adapter);
    });