How can I implement this?

Question

Java

Hello, I have a ListView which consists of 3 items. I need this element to be immediately selected at the start of the activity. And if the user clicked on another element of the list, then the one where the user clicked was highlighted. Here is what I do
in activity_main.xml

<RelativeLayout 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" android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
 
    <ListView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:id="@+id/listView"
       android:layout_alignParentTop="true"
       android:layout_centerHorizontal="true"
<!--установил цвет выделения -->
        android:listSelector="@color/item_color_test"
        android:choiceMode="singleChoice" />
</RelativeLayout>

MainActivity.java

package ru.domen.myapplication;
 
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
 
public class MainActivity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
 
        ListView listView = (ListView)findViewById(R.id.listView);
        String[] data = {
                "a","v","c"
        };
        listView.setAdapter(new ArrayAdapter<String>(this, R.layout.item, data));
        listView.setItemChecked(1, true);
        listView.setSelection(1);
        Log.v("test", "sel: " + listView.getCheckedItemPosition());
 
 
 
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
 
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
 
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
 
        return super.onOptionsItemSelected(item);
    }
}

I have a list, but the element I need is not selected, how can I solve this problem, what am I doing wrong?
Thank you very much in advance!

Answer 1

I tried many options, I can’t select it at startup, it only selects on click. Although the position of the element getCheckedItemPosition()is correct.
The best I could find is an article that says why you shouldn't do this.

Answer 2

What if it's like this?

<RelativeLayout 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=".MainActivity">

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:listSelector="@color/item_color_test"
        android:id="@+id/listView"/>

</RelativeLayout>

public class MainActivity extends AppCompatActivity {
    private final static String KEY = "selectedRow";

    private MyAdapter adapter;
    private int selectedItem = 1;

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

        ListView listView = (ListView) findViewById(R.id.listView);
        final String[] data = {
                "a","v","c"
        };
        if(savedInstanceState != null && savedInstanceState.containsKey(KEY))
        {
            selectedItem = savedInstanceState.getInt(KEY);
        }
        adapter = new MyAdapter(this, R.layout.item, data, selectedItem);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String selected = data[position];
                selectedItem = position;
                adapter.setSelectedRow(selectedItem);
            }
        });
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt(KEY, selectedItem);
    }    

    private class MyAdapter extends ArrayAdapter<String> {
        final int resId;
        int selectedRow;

        public MyAdapter(Context context, int resId, String[] data, int selectedRow) {
            super(context, resId, data);
            this.resId = resId;
            this.selectedRow = selectedRow;
            selectedColor = getResources().getColor(R.color.item_color_test);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            String string = getItem(position);

            if (convertView == null) {
                convertView = LayoutInflater.from(getContext()).inflate(resId, null);
            }
            TextView textView = (TextView) convertView;
            textView.setText(string);
            textView.setBackgroundColor(position == selectedRow ? selectedColor : 0x00000000);
            return convertView;
        }

        public void setSelectedRow(int row)
        {
            selectedRow = row;
            notifyDataSetInvalidated();
        }
    }
}

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:paddingTop="20dp"
    android:paddingBottom="20dp"
    android:paddingLeft="10dp"/>

You can do anything with the list string template in your adapter's own implementation.