搜索的项目在点击时给我错误的结果

Question

I have a list of China, USA, Canada, and Japan with a search bar on the action bar. Everything works well but when I click on the searched item it gives me a wrong result. For example, if I search for Canada I see the result for Canada but when I click on it, it shows me the details for China. What can I do for correct result on click? Below are the screenshot and code:-

package com.example.search;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.SearchView;
import androidx.appcompat.widget.Toolbar;

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

public class MainActivity extends AppCompatActivity {


    ListView listView;
    String[] nameList =

            {
                    "China",
                    "USA",
                    "Canada",
                    "Japan",
            };

    ArrayAdapter<String> adapter;

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


        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        listView = (ListView) findViewById(R.id.list);

        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, nameList);

        listView.setAdapter(adapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {

                if (position == 0)  {
                    Intent intent0 = new Intent(getBaseContext(), China.class);
                    startActivity(intent0);
                }
                if (position == 1) {
                    Intent intent1 = new Intent(getBaseContext(), USA.class);
                    startActivity(intent1);
                }
                if (position == 2) {
                    Intent intent2 = new Intent(getBaseContext(), Canada.class);
                    startActivity(intent2);
                }
                if (position == 3) {
                    Intent intent3 = new Intent(getBaseContext(), Japan.class);
                    startActivity(intent3);
                }
                {

                }


            }

        });



    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.toolbar_search_menu, menu);
        MenuItem menuItem = menu.findItem(R.id.action_search);
        SearchView searchView = (SearchView) menuItem.getActionView();
        searchView.setQueryHint("Search here!");

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return true;

            }

            @Override
            public boolean onQueryTextChange(String newText) {
                MainActivity.this.adapter.getFilter().filter(newText);
                return false;
            }
        });

        return super.onCreateOptionsMenu(menu);
    }
}


 

Answer 1

I see in your override onItemClick method you are starting different activity with respect to position, but your code will work only for your original item list that is {"China","USA","Canada","Japan"};

so what happens after you apply filter, your list in your adapter gets updated and so is your item positioning. following your example after user searched for "Canada" the list in adapter get updated to {"Canada"}. now as you can see at position 0 instead of "China" we have "Canada" now

Conclusion: When doing filtering we can never rely on positions of items as they can change. but what we can do is get current item at that position from adapter and match its data

Here you can Replace listView.setOnItemClickListener with the following code

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
   @Override
   public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
        
            String country = (listView.getItemAtPosition(position));
     
            if (country.equals("China"))  {
                Intent intent0 = new Intent(getBaseContext(), China.class);
                startActivity(intent0);
            }
            if (country.equals("USA"))  {
                Intent intent1 = new Intent(getBaseContext(), USA.class);
                startActivity(intent1);
            }
            if (country.equals("Canada"))  {
                Intent intent2 = new Intent(getBaseContext(), Canada.class);
                startActivity(intent2);
            }
            if (country.equals("Japan"))  {
                Intent intent3 = new Intent(getBaseContext(), Japan.class);
                startActivity(intent3);
            }
   }
});