Custom SimpleAdapter in Android with Example

package com.gfg.custom_simple_adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.IdRes;
import androidx.annotation.LayoutRes;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class CustomSimpleAdapter extends SimpleAdapter {

    private final Context mContext;
    private final int mResource;
    private final String[] mFrom;
    private final int[] mTo;
    private final List<? extends Map<String, ?>> mData;

    public CustomSimpleAdapter(Context context, List<? extends Map<String, ?>> data,
            @LayoutRes int resource, String[] from, @IdRes int[] to) {
        super(context, data, resource, from, to);
        this.mContext = context;
        this.mData = data;
        this.mResource = resource;
        this.mFrom = from;
        this.mTo = to;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        if (view == null) {
            LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(mResource, parent, false);
        }
        // Get the view in our case list_item.xml
        view = super.getView(position, view, parent);

        // Getting reference of ImageView that we
        // have used in our list_item.xml file
        // so that we can add user defined code
        ImageView avatarImageView = view.findViewById(R.id.avatarImageView);

        // Reference of TextView which is treated a title
        TextView titleTextView = view.findViewById(R.id.titleTextView);

        // Adding an clickEvent to the ImageView, as soon as we click this
        // ImageView we will see a Toast which will display a message
        // Note: this event will only fire when ImageView is pressed and
        //       not when whole list_item is pressed
        avatarImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(
                        mContext,
                        "Image with title " + titleTextView.getText() + " is pressed",
                        Toast.LENGTH_SHORT
                ).show();
            }
        });

        // Finally returning our view
        return view;
    }
}

package com.gfg.custom_simple_adapter;

import android.os.Bundle;
import android.widget.ListView;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MainActivity extends AppCompatActivity {

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

        // Because SimpleAdapter works with static
        // data so we need to initialize static data

        // This is the array for TitleText
        String[] titles = {"Mountain", "Flower", "Sky"};

        // This array is for SubtitleText
        String[] subtitles = {"This is a mountain", "This is a flower", "This is a beautiful sky"};

        // These are the Id's of the images that will be displayed as avatar
        int[] images = {R.drawable.k1, R.drawable.k2, R.drawable.k3};

        // Instantiating our data List, which is a list of HashMap
        List<HashMap<String, String>> data = new ArrayList<>();

        // Populating our data List with the
        // arrays that we have already defined
        for (int i = 0; i < titles.length; i++) {
            HashMap<String, String> cur = new HashMap<>();
            cur.put("titleText", titles[i]);
            cur.put("subtitleText", subtitles[i]);
            cur.put("avatarImage", String.valueOf(images[i]));
            data.add(cur);
        }

        // From and To array which will be used to map, HashMap values
        // to the Views that are defined in the XML file (in our case list_item.xml)
        String[] from = {"avatarImage", "titleText", "subtitleText"};
        int[] to = {R.id.avatarImageView, R.id.titleTextView, R.id.subtitleTextView};

        // Instantiating customSimpleAdapter with the above values
        CustomSimpleAdapter customSimpleAdapter = new CustomSimpleAdapter(this, data, R.layout.list_items, from, to);

        // Getting reference of listView which is defined in activity_main.xml
        ListView listView = findViewById(R.id.listView);

        // Finally, setting adapter to our customSimpleAdapter
        listView.setAdapter(customSimpleAdapter);
    }
}