在 notifyDataSetChanged 上未调用 GetView，ListView 卡住

Posted 2023-05-07

【中文标题】在 notifyDataSetChanged 上未调用 GetView，ListView 卡住

【英文标题】：GetView not called on notifyDataSetChanged, ListView is stuck

【发布时间】：2021-04-20 21:25:32

【问题描述】：

我有一个问题，我已经创建了自定义适配器，在联系人应用程序中对联系人对象进行自定义过滤，它可以很好地过滤联系人姓名，并且过滤后的联系人列表被正确保存。问题是当我在 searchView 中键入任何内容时，找到的行数是正确的，但有关找到的行的信息不正确。问题似乎与适配器中的 getView 函数有关，它不应该被调用。例如，如果我有三个联系人：“abc”、“aaa”、“aba”，并且它们按从上到下的顺序显示在开头，那么如果我在 searchView 中键入“ab”，那么它会找到 2 行，但它们仍然和开始时一样，它们应该是“abc”和“aba”，但它们是“abc”和“aaa”。适配器创建的第一个视图似乎由于某种原因被卡住了。

我的活动课：

package com.example.androidlab;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import androidx.appcompat.app.AppCompatActivity;

import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.Toast;

import java.lang.reflect.Type;
import java.util.ArrayList;

public class AllContactsActivity extends AppCompatActivity 
    static ArrayList<Contact> contacts = new ArrayList<>();
    ContactsAdapter contactsAdapter;

    ListView listView;
    SearchView searchView;

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

        FloatingActionButton addContact = findViewById(R.id.newContact);

        listView = findViewById(R.id.allContactsList);
        searchView = findViewById(R.id.searchContacts);

        SharedPreferences sharedPreferences = getApplicationContext().getSharedPreferences("com.tanay.thunderbird.contacts", Context.MODE_PRIVATE);
        Gson gson = new Gson();
        String json = sharedPreferences.getString("contacts", null);
        Type type = new TypeToken<ArrayList<Contact>>() 
        .getType();
        contacts = gson.fromJson(json, type);
        if (contacts == null) 
            contacts = new ArrayList<>();
        
        if (contacts.size() == 0)
            Toast.makeText(this, "There are no contacts.", Toast.LENGTH_LONG).show();

        contactsAdapter = new ContactsAdapter(this, contacts);
        listView.setAdapter(contactsAdapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() 
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) 
                Intent intent = new Intent(getApplicationContext(), EditContactActivity.class);
                intent.putExtra("noteID", position);
                startActivity(intent);
                finish();
            
        );

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() 
            @Override
            public boolean onQueryTextSubmit(String query) 
                contactsAdapter.getFilter().filter(query);
                return false;
            

            @Override
            public boolean onQueryTextChange(String query) 
                contactsAdapter.getFilter().filter(query);
                return false;
            
        );

        addContact.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View view) 
                Intent intent = new Intent(getApplicationContext(), NewContactActivity.class);
                startActivity(intent);
                finish();
            
        );

    


    @Override
    public void onBackPressed() 
        finish();
    

我的适配器类：

package com.example.androidlab;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class ContactsAdapter extends BaseAdapter implements Filterable 

    Context context;
    List<Contact> contacts;
    List<Contact> filteredContacts;
    ContactFilter mFilter = new ContactFilter();
    String filterString;

    ContactsAdapter(Context context, List<Contact> contacts) 
        this.context = context;
        this.contacts = contacts;
        filteredContacts = contacts;
    

    @Override
    public int getCount() 
        if(contacts.size() != filteredContacts.size() || filterString != null)
        
            return filteredContacts.size();
        
        else 
            filteredContacts = contacts;
            return contacts.size();
        
    

    @Override
    public Object getItem(int position) 
        return contacts.get(position);
    

    @Override
    public long getItemId(int position) 
        return contacts.indexOf(getItem(position));
    

    @Override
    public Filter getFilter() 
        return mFilter;
    

    private class ViewHolder 
        ImageView imageView;
        TextView name;
        TextView phoneNumber;
    

    @Override
    public View getView(int position, View convertView, ViewGroup parent) 
        ViewHolder holder = null;
            LayoutInflater mInflater = (LayoutInflater) context.getSystemService(AllContactsActivity.LAYOUT_INFLATER_SERVICE);
            if (convertView == null) 
                convertView = mInflater.inflate(R.layout.list_contacts, null);
                holder = new ViewHolder();

                holder.name = (TextView) convertView.findViewById(R.id.contactName);
                holder.imageView = (ImageView) convertView.findViewById(R.id.imageOfContact);
                holder.phoneNumber = (TextView) convertView.findViewById(R.id.phoneNumber);

                Contact contact;

                if(filteredContacts.size() != contacts.size()) contact = filteredContacts.get(position);
                else contact = contacts.get(position);

                if (contact.getAvatar() == null) 
                    if (contact.getGender() == true)
                        holder.imageView.setImageResource(R.drawable.ic_man);
                    else holder.imageView.setImageResource(R.drawable.ic_woman);
                 else 
                    byte[] decodedString = Base64.decode(contact.getAvatar(), Base64.DEFAULT);
                    Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
                    holder.imageView.setImageBitmap(decodedByte);
                
                holder.name.setText(contact.getName());
                holder.phoneNumber.setText(String.valueOf(contact.getPhoneNumber()));
            

        return convertView;
    

    private class ContactFilter extends Filter 
        @Override
        protected FilterResults performFiltering(CharSequence constraint) 

            filterString = constraint.toString().toLowerCase();

            FilterResults results = new FilterResults();

            final List<Contact> list = contacts;

            int count = list.size();
            final ArrayList<Contact> nList = new ArrayList<Contact>();

            for (int i = 0; i < count; i++) 
                if(contacts.get(i).getName().contains(filterString)) nList.add(contacts.get(i));
            

            results.values = nList;
            results.count = nList.size();
            return results;
        

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) 
            filteredContacts = (ArrayList<Contact>) results.values;
            notifyDataSetChanged();
        

    

编辑：我摆脱了 getView 函数中的 if(contentView == null) 并且一切正常

【参考方案1】：

检查convertView == null 应该只处理你的View 的膨胀和创建一个新的ViewHolder 其余的getView 代码应该始终运行。

public View getView(int position, View convertView, ViewGroup parent)  
    ViewHolder holder; 

    if (convertView == null) 
        convertView = mInflater.inflate(R.layout.list_contacts, null);
        // attach a new holder to the inflated view
        holder = new ViewHolder(); 
        convertView.setTag(holder); 
     else  
        // get an existing holder from the existing view
        holder = (ViewHolder) convertView.getTag(); 
     

    // update your holder here:
    // e.g. holder.name.setText(contact.getName());
    
    return convertView;