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DBILITY
안드로이드 SQLiteOpenHelper 구현 본문
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별거 없다. 그냥 유튭이나 블로그들에 잘 정리 되어 있다.
package com.example.mysqlite.helper
import android.content.ContentValues
import android.content.Context
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
import android.util.Log
class SqliteHelper(context: Context, name: String = "todo.db", version: Int = 1) :
SQLiteOpenHelper(context, name, null, version) {
override fun onCreate(db: SQLiteDatabase?) {
db?.execSQL(
"""create table todo (
|`no` integer primary key
|,content text
|,datetime integer
|)""".trimMargin()
)
Log.d("onCreate", db?.toString() ?: "What?!")
}
override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
//테이블구조에 변경사항이 있을 경우 생성자 호출할 때 버전을 넣으면 실행 됨
//아마 onCreate는 무조건 딱 한번만 실행(없으면 생성)이 되나 보다 그래서 스키마에 변경 사항이 필요할 때 요걸 쓰나 보다
//데이터를 보존한 상태에서 하고 싶다면 백업처리 후 삭제,신규 생성 후 데이터 저장, 백업삭제 이래야 하나 보다.
db?.run {
execSQL("create table todo_backup as select * from memo")
execSQL("drop table if exists todo")
onCreate(db)
execSQL("insert into todo(`no`,content,datetime) select `no`,content,datetime from todo_backup")
execSQL("drop table if exists todo_backup")
}
}
fun selectTodoList(): MutableList<Todo> {
val list = mutableListOf<Todo>()
val rd = readableDatabase
val cursor = rd.rawQuery("select * from todo", null)
while (cursor.moveToNext()) {
/*list.add(
Todo(
cursor.getLong(0),
cursor.getString(1),
cursor.getLong(2)
)
)*/
val no = cursor.getLong(cursor.getColumnIndexOrThrow("no"))
val content = cursor.getString(cursor.getColumnIndexOrThrow("content"))
val datetime = cursor.getLong(cursor.getColumnIndexOrThrow("datetime"))
list.add(Todo(no, content, datetime))
}
cursor.close()
rd.close()
return list
}
fun insertTodo(content: String, datetime: Long): Long {
val wd = writableDatabase
val values = ContentValues().apply {
put("content", content)
put("datetime", datetime)
}
val newRowId = wd.insert("todo", "", values)
wd.close()
return newRowId
}
fun updateTodo(todo:Todo) : Int {
val wd = writableDatabase
val values = ContentValues().apply {
put("content", todo.content)
put("datetime", todo.datetime)
}
//val rowId = wd.update("todo", values,"no=?", arrayOf(todo.no.toString()))
val rowId = wd.update("todo", values,"no=${todo.no}",null)
wd.close()
return rowId
}
fun deleteTodo(no:Long) : Int {
val wd = writableDatabase
val affectedRows = wd.delete("todo", "no=?", arrayOf(no.toString()))
//val affectedRows = wd.delete("todo","no=${todo.no}",null)
wd.close()
return affectedRows
}
/*companion object {
private const val DATABASE_VERSION = 1
private const val DATABASE_NAME = "todo.db"
private var instance: SqliteHelper? = null
@JvmStatic
fun getInstance(context: Context, version: Int = 1): SQLiteOpenHelper {
return if (instance == null) SqliteHelper(
context.applicationContext,
DATABASE_NAME,
if (DATABASE_VERSION == version) DATABASE_VERSION else version
)
else instance!!
}
}*/
}
data class Todo(val no: Long, val content: String, val datetime: Long)
package com.example.mysqlite
import android.os.Bundle
import android.util.Log
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
import com.example.mysqlite.databinding.ActivityMainBinding
import com.example.mysqlite.helper.SqliteHelper
import com.example.mysqlite.helper.Todo
class MainActivity : AppCompatActivity() {
private val binding by lazy {
ActivityMainBinding.inflate(layoutInflater)
}
private lateinit var helper : SqliteHelper
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
enableEdgeToEdge()
setContentView(binding.root)
ViewCompat.setOnApplyWindowInsetsListener(binding.main) { v, insets ->
val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
insets
}
helper = SqliteHelper(this)
Log.d("helper",helper.toString())
Log.d("path",this.getDatabasePath(helper.databaseName).toString())
/*val rowId = helper.insertTodo("do something",System.currentTimeMillis())
Log.d("rowId",rowId.toString())*/
/*val rowId = helper.updateTodo(1)
Log.d("rowId",rowId.toString())*/
val affectedRows = helper.deleteTodo(1)
Log.d("affectedRows",affectedRows.toString())
}
}
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