Flashlight Android App

 <?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"
    android:orientation="vertical"
    tools:context=".MainActivity"
    tools:ignore="HardcodedText">
    <ImageView
        android:id="@+id/imgonoff"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_marginTop="228dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.554"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/txtonoff"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="52dp"
        android:text="Flashlight is turned OFF"
        android:textSize="25sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imgonoff" />
  </androidx.constraintlayout.widget.ConstraintLayout>

 import android.annotation.SuppressLint
 import android.content.Context
 import android.hardware.camera2.CameraAccessException
 import android.hardware.camera2.CameraManager
 import android.os.Bundle
 import android.widget.ImageView
 import android.widget.TextView
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity


 class MainActivity : AppCompatActivity() {
    private var imgonoff: ImageView? = null
    private var txtonoff: TextView? = null
    private var isonoroff: Boolean? = null
    private var cameraManager: CameraManager? = null
    private var getCameraID: String? = null

    @SuppressLint("MissingInflatedId")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        isonoroff = false
        imgonoff = findViewById(R.id.imgonoff)
        txtonoff = findViewById(R.id.txtonoff)
        cameraManager = getSystemService(Context.CAMERA_SERVICE) as CameraManager
        imgonoff?.setBackgroundResource(R.drawable.off)
        try {
            getCameraID = cameraManager!!.cameraIdList[0]
        } catch (e: CameraAccessException) {
            e.printStackTrace()
        }
        imgonoff?.setOnClickListener {
            if (isonoroff == true) {
                try {
                    imgonoff?.setBackgroundResource(R.drawable.off)
                    cameraManager!!.setTorchMode(getCameraID!!, false)
                    Toast.makeText(
                        this@MainActivity,
                        "Flashlight is turned OFF",
                        Toast.LENGTH_SHORT
                    )
                        .show()
                    txtonoff?.setText("Flashlight is turned OFF")
                } catch (e: CameraAccessException) {
                    e.printStackTrace()
                }
                isonoroff = false
            } else {
                try {
                    imgonoff?.setBackgroundResource(R.drawable.on)
                    cameraManager!!.setTorchMode(getCameraID!!, true)
                    txtonoff?.setText("Flashlight is turned ON")
                    Toast.makeText(this@MainActivity, "Flashlight is turned ON", Toast.LENGTH_SHORT)
                        .show()
                } catch (e: CameraAccessException) {

                    e.printStackTrace()
                }
                isonoroff = true
            }
        }
    }


    override fun finish() {
        super.finish()
        try {
            cameraManager!!.setTorchMode(getCameraID!!, false)

            Toast.makeText(this@MainActivity, "Flashlight is turned OFF", Toast.LENGTH_SHORT).show()
        } catch (e: CameraAccessException) {
           e.printStackTrace()
        }
     }

 }