SQLiteOpenHelperActivity.kt

package com.leonidivankin.draftsandroid.articles.db

import android.content.ContentValues
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity

class SQLiteOpenHelperActivity : AppCompatActivity() {

    private val db by lazy {
        object : SQLiteOpenHelper(this, "colors_db", null, 1) {
            override fun onCreate(db: SQLiteDatabase) {
                db.execSQL("CREATE TABLE $TABLE_NAME (_id INTEGER PRIMARY KEY AUTOINCREMENT, color TEXT)")
            }
            override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {}
        }.readableDatabase
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Thread{
            insert( "green")
            insert( "red")
            insert( "blue")
            get()
        }.start()
    }

    private fun insert(color: String) {
        val contentValues = ContentValues()
        contentValues.put(COLUMN_NAME, color)
        db.insert(TABLE_NAME, null, contentValues)
    }

    private fun get() {
        val cursor = db.query(TABLE_NAME, arrayOf("_id", COLUMN_NAME), null, null, null, null, null)
        var i = 0
        while (!cursor.isLast) {
            cursor.moveToPosition(i)
            val id = cursor.getInt(0)
            val color = cursor.getString(1)
            Log.d("DbExample", "$id $color")
            i++
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        db.close()
    }

    companion object {
        const val TABLE_NAME = "colors"
        const val COLUMN_NAME = "color"
    }
}