DatabaseHelper.java

package com.emreedemir.bookapplication;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.Nullable;

import java.util.ArrayList;
import java.util.List;

public class DatabaseHelper extends SQLiteOpenHelper
{
    public DatabaseHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase)
    {
        String CREATE_TABLE = "CREATE TABLE " + BookDatabaseConstant.BOOK_DATABASE_NAME + "("
                + BookDatabaseConstant.CONTACTS_COLUMN_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT,"
                + BookDatabaseConstant.CONTACTS_COLUMN_NAME+ " TEXT,"
                + BookDatabaseConstant.CONTACTS_COLUMN_SURNAME + " TEXT,"
                + BookDatabaseConstant.CONTACTS_COLUMN_PHONE + " TEXT" +
                ")";

        sqLiteDatabase.execSQL(CREATE_TABLE);
    }

    public void addPersonToDatabase(Person person)
    {
        SQLiteDatabase sqLiteDatabase =this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(BookDatabaseConstant.CONTACTS_COLUMN_NAME,person.getName());
        values.put(BookDatabaseConstant.CONTACTS_COLUMN_SURNAME,person.getSurname());
        values.put(BookDatabaseConstant.CONTACTS_COLUMN_PHONE,person.getTelephoneNumber());

        sqLiteDatabase.insert(BookDatabaseConstant.CONTACTS_TABLE_NAME,null,values);

        sqLiteDatabase.close();
    }

    public void deletePersonFromDatabase(Person person)
    {
        SQLiteDatabase database=this.getWritableDatabase();

        database.execSQL("DELETE FROM " +BookDatabaseConstant.CONTACTS_TABLE_NAME+" WHERE "+BookDatabaseConstant.CONTACTS_COLUMN_NAME+"='"+person.getName()+"'and'"+ BookDatabaseConstant.CONTACTS_COLUMN_SURNAME +"='"+person.getSurname()+"'and'"+BookDatabaseConstant.CONTACTS_COLUMN_PHONE+"='"+person.getTelephoneNumber());

        database.close();
    }


    public List<Person> getAllPersonFromDatabase()
    {

        List<Person> personList = new ArrayList<>();



        String selectQuery = "SELECT  * FROM " +BookDatabaseConstant.CONTACTS_TABLE_NAME + " ORDER BY " +
                BookDatabaseConstant.COLUMN_TIMESTAMP + " DESC";

        SQLiteDatabase database =this.getWritableDatabase();

        Cursor cursor = database.rawQuery(selectQuery,null);

        if(cursor.moveToNext())
        {
            do {
                Person person =
                        new Person(
                        cursor.getString(cursor.getColumnIndex(BookDatabaseConstant.CONTACTS_COLUMN_NAME)),
                        cursor.getString(cursor.getColumnIndex(BookDatabaseConstant.CONTACTS_COLUMN_SURNAME)),
                                cursor.getString(cursor.getColumnIndex(BookDatabaseConstant.CONTACTS_COLUMN_PHONE)));

                        personList.add(person);

            }while (cursor.moveToNext());
        }

        return  personList;
    }
    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1)
    {

    }
}