Crate a Database, Read, Write, Get Data – Basic Easy Guide

    public class MainActivity extends AppCompatActivity {
     
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
     
            //crate a database
            SQLiteDatabase sqLiteDatabase = getBaseContext().openOrCreateDatabase("sqllite-db1.db", MODE_PRIVATE, null);
     
            //create a table in database
     
            sqLiteDatabase.execSQL("CREATE TABLE IF NOT EXISTS contacts(name TEXT, phone INTEGER, email TEXT)");
     
            //add data
            sqLiteDatabase.execSQL("INSERT INTO contacts VALUES ('MyName', 32543446, 'myemail@domain/com');");
            sqLiteDatabase.execSQL("INSERT INTO contacts VALUES ('yourName', 32543446, 'yourmail@domain/com');");
     
            //retrieve the data
            Cursor query = sqLiteDatabase.rawQuery("SELECT * from contacts", null);
     
            if(query.moveToFirst()) { //return false if there there is no data (check if the first record has data)
     
                //Cycle through all records in all tables rows
                //do = will execute at least once
                do {
                    String name = query.getString(0);
                    int phone = query.getInt(1);
                    String email = query.getString(2);
     
                    Toast.makeText(this, "Name = " + name + ", phone = " + phone + ", email = " + email, Toast.LENGTH_SHORT).show();
                } while(query.moveToNext());
     
            }else {
                Toast.makeText(this, "Error retrieving data", Toast.LENGTH_SHORT).show();
            }
            sqLiteDatabase.close();
        }
    }