Ask for Runtime Permissions in Android

runtime_permission.kt

private val requiredPermissionList = arrayOf(
        //list of permissions
        Manifest.permission.WRITE_EXTERNAL_STORAGE,
        Manifest.permission.READ_EXTERNAL_STORAGE
    )

  private fun checkAndRequestPermission(): Boolean {
        val permissionsNeeded = ArrayList<String>()

        for (permission in requiredPermissionList) {
            if (ContextCompat.checkSelfPermission(this, permission) !=
                PackageManager.PERMISSION_GRANTED
            ) {
                permissionsNeeded.add(permission)
            }
        }

        if (permissionsNeeded.isNotEmpty()) {
            ActivityCompat.requestPermissions(
                this,
                permissionsNeeded.toTypedArray(),
                PERMISSION_CODE
            )
            return false
        }

        return true
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        when (requestCode) {
            PERMISSION_CODE -> if (grantResults.isNotEmpty()) {
                val readPermission = grantResults[0] == PackageManager.PERMISSION_GRANTED
                val writePermission = grantResults[1] == PackageManager.PERMISSION_GRANTED
                if (readPermission && writePermission)
                    launchPdf()
                else {
                    Toast.makeText(this, " Permission Denied", Toast.LENGTH_SHORT).show()
                }
            }
        }
    }