For more details, visit this link: https://medium.com/@birdeveloper/upload-files-to-android-firebase-stroage-4228fdd8d47f

Upload files to Android Firebase Stroage

val storageRef = Firebase.storage.reference
    fun uploadPhoto(photoUrl: Uri, onComplete: (downloadUrl: String?) -> Unit){
                val profilePhotosRef = storageRef.child("photos/${getPref().firebaseUuid}")
                val metadata = storageMetadata {
                    contentType = "image/jpeg"
                }
                d { "uploadPhoto: $photoUrl" }
                val photoFile = photoUrl
                val uploadTask = profilePhotosRef.putFile(photoFile,metadata)

                uploadTask.addOnProgressListener { taskSnapshot ->
                    val progress = (100.0 * taskSnapshot.bytesTransferred) / taskSnapshot.totalByteCount
                    d { "Upload is $progress% done" }
                }.addOnPausedListener {
                    d { "Upload is paused" }
                }.addOnFailureListener {
                    d { "failure: ${it.printStackTrace()}" }
                }.addOnSuccessListener {
                    profilePhotosRef.downloadUrl.addOnSuccessListener {
                        d { "downloadUrl: $it" }
                        onComplete(it.toString())
                    }
                }
    }