processPdf.kt

 private fun checkWritePermissionAndProcessPdf() {
        ActivityCompat.requestPermissions(
            requireActivity(),
            arrayOf(android.Manifest.permission.WRITE_EXTERNAL_STORAGE), REQUEST_CODE
        )
        if (checkSelfPermission(
                requireContext(),
                android.Manifest.permission.WRITE_EXTERNAL_STORAGE
            )
            == PackageManager.PERMISSION_GRANTED
        ) {
            processPdf()
        } else {
           // show Snackbar toast message
        }
    }

 private fun processPdf() {
        val pageInfo = PdfDocument.PageInfo.Builder(2250, 1400, 1).create()
        val document = PdfDocument()
        val page = document.startPage(pageInfo)
        val content =
            this.requireActivity().window.decorView.findViewById<ConstraintLayout>(R.id.your_parent_view)

        content.measure(2480, 3508)
        content.layout(0, 0, 2480, 3508)

        val measureWidth = View.MeasureSpec.makeMeasureSpec(
            page.canvas.width,
            View.MeasureSpec.EXACTLY
        )
        val measuredHeight = View.MeasureSpec.makeMeasureSpec(
            page.canvas.height,
            View.MeasureSpec.EXACTLY
        )

        content.measure(measureWidth, measuredHeight)
        content.layout(0, 0, page.canvas.width, page.canvas.height)
        content.draw(page.canvas)
   
        document.finishPage(page)
        val pdfFolder = File(
            requireContext().externalCacheDir?.absolutePath,
            "your child path here"
        )

        if (!pdfFolder.exists()) {
            pdfFolder.mkdirs()
            Timber.i("Pdf Directory created")
        }

        //Create time stamp
        val date = Date()
        val timeStamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(date)
        val fileNamePath = "$pdfFolder$timeStamp.pdf"
        val myFile = File(fileNamePath)

        val output: OutputStream = FileOutputStream(myFile)
   
              try {
                    document.writeTo(output)
                    //you can restore the parent layout params here
                } catch (e: IOException) {
                   
                }
    }