[코틀린코드연습장] SQLite

간단한 SQLite 연습.

[Main.kt]

class MainActivity : AppCompatActivity() {

    var dbHandler : DatabaseHelper? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        dbHandler = DatabaseHelper(this)

        button.setOnClickListener {
            if(validation()) {
                val users: Users = Users()
                var success : Boolean = false
                users.firstName = editText.text.toString()
                users.lastName = editText2.text.toString()

                success = dbHandler!!.addUser(users)

                if(success) {
                    val toast = Toast.makeText(this,
                        "Save Successfully",
                        Toast.LENGTH_SHORT).show()
                }
            }
        }

        button2.setOnClickListener {
            var users = dbHandler!!.getAllUser()
            textView.setText(users)
        }
    }

    fun validation() : Boolean {
        var validate : Boolean = false

        if(!editText.text.isEmpty() &&
                !editText2.text.isEmpty()) {
            validate = true
        }else {
            validate = false
            val toast = Toast.makeText(this, "Fill all details",
                Toast.LENGTH_SHORT).show()
        }
        return validate
    }

}

[DBHelper.kt]

class DatabaseHelper(context: Context)
    :SQLiteOpenHelper(context, DB_NAME, null, DB_VERSION) {

    companion object {
        private val DB_NAME = "UserDB"
        private val DB_VERSION = 1
        private val TABLE_NAME = "users"
        private val ID = "id"
        private val FIRST_NAME = "FirstName"
        private val LAST_NAME = "LastName"
    }

    override fun onCreate(db: SQLiteDatabase?) {
        val createTable =
            "CREATE TABLE $TABLE_NAME" +
            "($ID Integer PRIMARY KEY," +
            "$FIRST_NAME TEXT," +
            "$LAST_NAME TEXT)"
        db?.execSQL(createTable)
    }

    override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {}

    fun addUser(user: Users) : Boolean {

        val db = this.writableDatabase
        val values = ContentValues()

        values.put(FIRST_NAME, user.firstName)
        values.put(LAST_NAME, user.lastName)

        val _success = db.insert(TABLE_NAME, null, values)
        db.close()

        return (Integer.parseInt("$_success") != -1)
    }

    fun getAllUser() : String {

        var allUser: String = "";
        val db = readableDatabase
        val selectALLQuery = "SELECT * FROM $TABLE_NAME"
        val cursor = db.rawQuery(selectALLQuery, null)
        var id : String =""
        var firstName = ""
        var lastName = ""
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    id = cursor.getString(cursor.getColumnIndex(ID))
                    firstName = cursor.getString(cursor.getColumnIndex(FIRST_NAME))
                    lastName = cursor.getString(cursor.getColumnIndex(LAST_NAME))

                    allUser = "$allUser \n $id $firstName $lastName"

                } while (cursor.moveToNext())
            }
        }
        cursor.close()
        db.close()
        return allUser
    }

}

[User.class]

class Users {
    var id : Int = 0
    var firstName : String = ""
    var lastName : String = ""
}