【Kotlin】AndroidStudio DateFormatのエラー

Question

前提・実現したいこと

はじめてのAndroidプログラミング第４版という書籍で勉強しています．
アラームを製作しようとしていますが，以下のエラーがでます．
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発生している問題・エラーメッセージ

Compilation error. See log for more details
Type mismatch: inferred type is CharSequence! but Editable! was expected
Unresolved reference: format

該当のソースコード

package com.example.gomidashihome1

import android.annotation.SuppressLint
import android.app.AlarmManager
import android.app.KeyguardManager
import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import android.icu.text.SimpleDateFormat
import android.os.Build
import android.os.Bundle
import android.view.WindowManager.LayoutParams.*
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_alarm.*
import java.text.ParseException
import java.util.*
import java.lang.IllegalArgumentException
import java.text.DateFormat
import java.util.regex.Pattern
import kotlin.text.format as format1

@Suppress("UNREACHABLE_CODE", "DEPRECATION", "CAST_NEVER_SUCCEEDS")
//@Suppress("DEPRECATION")
class alarmActivity : AppCompatActivity(),TimeAlertDialog.Listener
    ,DatePickerFragment.onDateSelectedListener
    ,TimePickerFragment.OnTimeSelectedListener {

    override fun getUp() {
        finish()
    }


    override fun onSelected(year: Int, month: Int, date: Int) {
        //DateFormat.DateFormat = android.text.format.DateFormat.getDateFormat(applicationContext)
        //val dateText = DateFormat.format(Calendar.getInstance())
        val c = Calendar.getInstance()
        c.set(year, month, date)
        dateText.text = android.text.format.DateFormat.format("yyyy/MM/dd", c )
    }

    @SuppressLint("SetTextI18n")
    override fun onSelected(hourOfDay: Int, minute: Int) {

        timeText.text = "%1$02d:%2$02d".format(hourOfDay,minute)
    }

    override fun onPositiveClick() {
        finish()
    }


    override fun snooze() {
        val calendar = Calendar.getInstance()
        calendar.timeInMillis = System.currentTimeMillis()
        calendar.add(Calendar.MINUTE,5)
        setAlarmManager(calendar)
        finish()
    }


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        if (intent?.getBooleanExtra("onReceive", false) == true) {
            when {
                Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1 -> {
                    setShowWhenLocked(true)
                    setTurnScreenOn(true)
                    val keyguardManager = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
                    keyguardManager.requestDismissKeyguard(this, null)
                }
                Build.VERSION.SDK_INT >= Build.VERSION_CODES.O -> {
                    window.addFlags(
                        FLAG_TURN_SCREEN_ON or FLAG_SHOW_WHEN_LOCKED
                    )
                    val keyguardManager =
                        getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
                    keyguardManager.requestDismissKeyguard(this, null)
                }
                else -> window.addFlags(
                    FLAG_TURN_SCREEN_ON or FLAG_SHOW_WHEN_LOCKED or FLAG_DISMISS_KEYGUARD
                )
            }


            val dialog = TimeAlertDialog()
            dialog.show(supportFragmentManager, "alert_dialog")
        }

        setContentView(R.layout.activity_alarm)

        setalarm.setOnClickListener {
            val date = "${dateText.text}${timeText.text}".toDate()
            when {
                date != null -> {
                    val calendar = Calendar.getInstance()
                    calendar.time = date
                    setAlarmManager(calendar)
                    Toast.makeText(
                        this, "アラームをセットしました",
                        Toast.LENGTH_SHORT
                    ).show()
                }
                else -> {
                    Toast.makeText(
                        this, "日付の形式が正しくありません",
                        Toast.LENGTH_SHORT
                    ).show()
                }
            }

            cancelalarm.setOnClickListener {
                cancelAlarmManager()
            }

            dateText.setOnClickListener {
                val dialog = DatePickerFragment()
                dialog.show(supportFragmentManager, "date_dialog")
            }
            timeText.setOnClickListener {
                val dialog = TimePickerFragment()
                dialog.show(supportFragmentManager, "time_dialog")
            }
        }
    }

    private fun setAlarmManager(calendar: Calendar){
        val am = getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val intent = Intent(this,AlarmBroadcastReceiver::class.java)
        val pending = PendingIntent.getBroadcast(this,0,intent,0)
        when{
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP -> {
                val info = AlarmManager.AlarmClockInfo(calendar.timeInMillis, null)
                am.setAlarmClock(info,pending)
            }
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT ->{
                am.setExact(AlarmManager.RTC_WAKEUP,calendar.timeInMillis,pending)
            }else ->{
                am.set(AlarmManager.RTC_WAKEUP,calendar.timeInMillis,pending)
            }
        }
    }
    private fun cancelAlarmManager(){
        val am = getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val intent = Intent(this,AlarmBroadcastReceiver::class.java)
        val pending = PendingIntent.getBroadcast(this,0,intent,0)
        am.cancel(pending)
    }

    @SuppressLint("SimpleDateFormat")
    private fun String.toDate(pattern:String = "yyyy/MM/dd HH:mm"):Date?{
        return try {
            SimpleDateFormat(pattern).parse(this)
        }catch (e:IllegalArgumentException){
            return null
        }catch (e:ParseException){
            return null
        }
    }
}

試したこと

初心者のため，書籍通りにしかできていません．

補足情報（FW/ツールのバージョンなど）

開発環境は
Android Studio3.4.1
Windows10
です．

Answer 1

dateText.setText(android.text.format.DateFormat.format("yyyy/MM/dd", c ))

でどうでしょう．

Comments

[murata2019]

提案して頂いた方法で解決しました。ありがとうございました。