A custom view for controlling camera

ControlView.kt

class ControlView : LinearLayout {

    private var isLongPressed: Boolean = false
    private var flashMode: FlashMode = FlashMode.FLASH_MODE_OFF
    private var listener: Listener? = null

    private val timerView = TimerView(context)
        .apply {
            layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)
            visibility = View.INVISIBLE
        }.also { addView(it) }

    private val layoutControls = LinearLayout(context).apply {
        layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT).apply {
            orientation = HORIZONTAL
            topMargin = 5.px
        }
    }.also { addView(it) }

    private val ivFlash = ImageButton(context).apply {
        layoutParams = LayoutParams(48.px, 48.px).apply {
            gravity = Gravity.CENTER
        }
        setImageResource(R.drawable.ic_baseline_flash_off_24)
        setBackgroundColor(Color.TRANSPARENT)
        setOnClickListener { toggleFlash() }
    }.also { layoutControls.addView(it) }

    private val ivCapture = ImageButton(context).apply {
        layoutParams = LayoutParams(70.px, 70.px).apply {
            setMargins(70.px, 20.px, 70.px, 20.px)
            gravity = Gravity.CENTER
        }
        setImageResource(R.drawable.ic_circle_line_white_70)
        setBackgroundColor(Color.TRANSPARENT)
    }.also {
        isHapticFeedbackEnabled = true
        layoutControls.addView(it)
    }

    private val ivSwitchCam = ImageButton(context).apply {
        layoutParams = LayoutParams(48.px, 48.px).apply {
            gravity = Gravity.CENTER
        }
        setImageResource(R.drawable.ic_baseline_flip_camera_24)
        setBackgroundColor(Color.TRANSPARENT)
        setOnClickListener {
            it.startRotateAnimation()
            listener?.toggleCamera()
        }
    }.also { layoutControls.addView(it) }

    private val tvInfo = TextView(context).apply {
        layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT).apply {
            gravity = Gravity.CENTER
            topMargin = 5.px
        }
        setTextColor(Color.WHITE)
        setTextSize(TypedValue.COMPLEX_UNIT_SP, 12f)
        text = "Hold for Video, tap for Photo"
    }.also { addView(it) }

    var flashVisibility:Boolean = true
        set(value) {
            field = value
            ivFlash.visibility = if (value) View.VISIBLE else View.INVISIBLE
        }

    var cameraToggleVisibility:Boolean = true
        set(value) {
            field = value
            ivSwitchCam.visibility = if (value) View.VISIBLE else View.INVISIBLE
        }

    constructor(context: Context) : this(context, null)
    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(
        context,
        attrs,
        defStyleAttr
    ) {
        setPadding(16.px)
        setBackgroundColor(Color.TRANSPARENT)
        gravity = Gravity.CENTER
        orientation = VERTICAL
    }

    fun setListener(listener: Listener?) {
        this.listener = listener
    }

    fun getFlashMode() = flashMode
    
    //...
}