Could you give me most simple code in Kotlin ?
I tried to find good example in seraching with Google, after 5 hours or more, I could NOT find what I want.
I would like to update done marks for solved Quiz like this photo.
from chk[1] to chk[20]
not yet : 0
done : 2
// 2 is similar Victory Sign.
for example, if solved Quiz Number “1”
chk[1] = 2
var chk_Q: Array<Int> = arrayOf (
0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
)
Now, while app is active, keep data 0 or 2. However, once app finished, chk_Q1 to [20] back to 0.
So, I would like to save data in checkDone.csv.
My textbook not explained how to save and read CSV file.
Bellow code is not worked as I want.
openFileOutput("checkDone.csv", MODE_PRIVATE)
.bufferedWriter().use {
for (i in 1..10) {
it.write(chk_Q[i].toString())
}
}
openFileInput("checkDone.csv", MODE_PRIVATE)
.bufferedReader().forEachLine {
str.append(it)
str.append(System.getProperty("line.separator"))
}
================================================== =
With Text File is done
================================================== =
MainActivity.kt
================================================== =
package com.surlofia.csv_exists_write_read
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import com.surlofia.csv_exists_write_read.databinding.ActivityMainBinding
import java.io.*
var chk_Q: Array<Int> = arrayOf (
0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
)
class MainActivity : AppCompatActivity() {
// View Binding Class のインスタンス
// lateinit で宣言し初期化タイミングを onCreate() まで遅らせる
// activity_main.xml の場合、ActivityMainBinding
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// setContentView(R.layout.activity_main) をコメントに変えた
// bindingのイニシャライズ
// super.onCreate(savedInstanceState) 直下に書く！！
// Binding Classに含まれる静的 inflate() メソッドを呼び出す
binding = ActivityMainBinding.inflate(layoutInflater)
// root view への参照を取得
val view = binding.root
// view をsetContentView()にセット
setContentView(view)
// bindingのイニシャライズ 完了
// Android - ファイル入出力の例（Read、Write、内部、外部ストレージ）
// https://codechacha.com/ja/android-read-write-file/
// Load saved data at game startup.
// ゲーム起動時に、セーブデータを読み込んでおく
val filePath = filesDir.path + "/memo.dat"
val file = File(filePath)
if (isFileExists(file)) {
readTextFromFile(filePath)
}
// Game Program Run
// and save Data
writeTextToFile(filePath)
binding.fileExists.text = isFileExists(file).toString()
}
// Kotlinにファイルが存在するかどうかを確認します
// https://www.techiedelight.com/ja/check-if-a-file-exists-in-kotlin/
private fun isFileExists(file: File): Boolean {
return file.exists() && !file.isDirectory
}
// Android - ファイル入出力の例（Read、Write、内部、外部ストレージ）
// https://codechacha.com/ja/android-read-write-file/
// &
// TECHNICAL MASTER はじめてのAndroidアプリ開発 Kotlin編 (TECHNICAL MASTER 98)
// https://www.amazon.co.jp/dp/B09MHF7F6N/ref=dp_kinw_strp_1
private fun readTextFromFile(path: String) {
val file = File(path)
val fileReader = FileReader(file)
val bufferedReader = BufferedReader(fileReader)
/*
val readString = StringBuilder()
bufferedReader.forEachLine {
readString.append(it)
readString.append(System.getProperty("line.separator"))
}
binding.readFile.text = readString
*/
// Let'sプログラミング
// Home › Java入門 › テキストファイルの入出力
// まとめてテキストを読む
// https://www.javadrive.jp/start/stream/index3.html
chk_Q[0] = 0
for (i in 1 .. 20) {
chk_Q[i] = bufferedReader.readLine().toInt()
}
bufferedReader.close()
var tempString = ""
for(i in 0 .. 20) {
tempString = tempString +i + "-->" + chk_Q[i] + "n"
}
binding.readFile.text = tempString
}
// Android - ファイル入出力の例（Read、Write、内部、外部ストレージ）
// https://codechacha.com/ja/android-read-write-file/
private fun writeTextToFile(path: String) {
val file = File(path)
val fileWriter = FileWriter(file, false)
val bufferedWriter = BufferedWriter(fileWriter)
for (i in 0 .. 20) {
chk_Q[i] = 2
bufferedWriter.append(chk_Q[i].toString())
bufferedWriter.newLine()
}
bufferedWriter.close()
/*
bufferedWriter.append("Test1n")
bufferedWriter.append("Test2")
bufferedWriter.newLine()
bufferedWriter.append("Test3n")
bufferedWriter.close()
*/
}
}
===================================
activity_main.xml
===================================
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/fileExists"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Hello World!"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/readFile"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/fileExists" />
</androidx.constraintlayout.widget.ConstraintLayout>