java - android中 ListView 中的重复值

Question

我将我的数据库值提取到自定义 ListView，但每当从我的 MainActivity 转到我的 ExistingPatient Activity 类时，它都会在 Listview 中创建我的数据的重复值。我的 MainActivity 仅包含一个按钮，在该按钮中，我使用 Intent 转到 ExistingPatient Activity 。

list_adapter.java

package com.example.voiceprescription;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.ArrayList;

public class list_adapter extends ArrayAdapter<Patientinfo> {
    private Context context;
    ArrayList<Patientinfo> info;

    public list_adapter(Context context, ArrayList<Patientinfo> info) {
        super(context,R.layout.cutomlist,info);
        this.context = context;
        this.info = info;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {


            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.cutomlist, parent, false);

            TextView tvname = convertView.findViewById(R.id.tv_Cname);
            TextView tvphone = convertView.findViewById(R.id.tv_Cphone);

            tvname.setText(info.get(position).getName());
            tvphone.setText(info.get(position).getPhone());

            return convertView;
        }

}

存在病人.java

package com.example.voiceprescription;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

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;

public class Exsistinpatient extends AppCompatActivity {

    ListView list;
    DatabaseReference reff;
    FirebaseDatabase database;
    list_adapter adapter;
    Patientinfo patientinfo;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_exsistinpatient);

        Intent intent=new Intent();


        list=findViewById(R.id.list);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent=new Intent(Exsistinpatient.this,Editinfo.class);
                intent.putExtra("index",position);
                startActivityForResult(intent,0);
            }
        });


        patientinfo=new Patientinfo();

        database=FirebaseDatabase.getInstance();
        reff=database.getReference("Patients");
        reff.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for(DataSnapshot data:dataSnapshot.getChildren()){

                    patientinfo=data.getValue(Patientinfo.class);
                    publicarray.info.add(patientinfo);
                }

                adapter=new list_adapter(Exsistinpatient.this,publicarray.info);
                list.setAdapter(adapter);
            }

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

            }
        });


    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode==0){
            adapter.notifyDataSetChanged();
        }
    }
}

Answer 1

尝试在每次启动时清除列表，这对我使用 RecyclerView 时有帮助，我认为这里有同样的问题