MainActivity.java

package nofieanggraeni.blogspot.com.gridview;

import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    //Deklarasi Variabel GridView
    protected GridView TampilanGrid;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getSupportActionBar().setTitle("Sosial Media dan Sistem Operasi");
        TampilanGrid = findViewById(R.id.gridview);
        //Menerapkan adapter pada GridView
        TampilanGrid.setAdapter(new ImageAdapter( this));
        //menerapkan listener untuk menangani kejadian saat salah satu item di klik
        TampilanGrid.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "" + position, Toast.LENGTH_SHORT).show();
            }
        });
    }

    class ImageAdapter extends BaseAdapter{
        private int[] gambar = { R.drawable.android, R.drawable.apple, R.drawable.windows, R.drawable.facebook, R.drawable.instagram,
                R.drawable.twitter, R.drawable.whatsapp, R.drawable.telegram, R.drawable.messenger,
                R.drawable.tiktok, R.drawable.line, R.drawable.youtube, R.drawable.opera, R.drawable.firefox };
        private Context mContext;

        ImageAdapter(Context c) {
            mContext = c;
        }
        public int getCount(){
            return gambar.length;
        }
        public Object getItem(int position) {
            return null;
        }
        public long getItemId(int position) {
            return 0;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView;
            if (convertView == null) {
                imageView = new ImageView(mContext);
                imageView.setLayoutParams(new ViewGroup.LayoutParams(240, 240));
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                imageView.setPadding(4,4,4,4);
            } else {
                imageView = (ImageView) convertView;
            }

            imageView.setImageResource(gambar[position]);
            return imageView;
        }
    }
}