Kotlin Firebase Storage - Upload Data from Memory, Local File, Stream

Firebase Cloud Storage helps us upload and share rich content data. Data is stored in a Google Cloud Storage bucket. With Firebase, we can perform robust operations (download/upload) regardless of network quality with strong security (Cloud Storage integrates with Firebase Authentication) and high scalability.

In this tutorial, we’re gonna look at ways to upload data from Memory, Local file, Stream in an Android App using Firebase Storage with Kotlin.

I. How to upload file

To use the Firebase Storage to upload data, we need:
– add Firebase to Android App & enable Firebase Auth
– create a reference to the full path of the file, including the file name
– upload data using putBytes() for in-memory data, putStream() for stream data, putFile() for local file.

0. Add Firebase to Android App

0.1 Add Firebase Storage

Steps to import and enable Firebase Storage is just like steps for Firebase Auth.
Just follow: Add_Firebase_to_Android_Project

0.2 Add Firebase Auth

By default, only authenticated users can upload or download data, so we need Firebase Authentication for next step.
Go to Your Firebase Project Console -> Authentication -> SIGN-IN METHOD -> Enable Email/Password.

To do without setting up Authentication, we can change the rules in the Firebase Console -> choose Project -> Storage section on the left -> Rules tab:

// change the code below

service firebase.storage {

match /b/{bucket}/o {

match /{allPaths=**} {

allow read, write: if request.auth != null;

}

0.3 Check

After adding Firebase Auth & Realtime DB, we can see:

– build.gradle (project-level):

buildscript {

// ...

dependencies {

// ...

classpath 'com.google.gms:google-services:3.1.0'

}

– build.gradle (App-level):

dependencies {

// ...

implementation 'com.google.firebase:firebase-auth:11.0.4'

implementation 'com.google.firebase:firebase-storage:11.0.4'

}

apply plugin: 'com.google.gms.google-services'

– google-services.json file:
kotlin-firebase-storage-json-file

1. Create a Reference

We cannot upload data with a reference to the root of Google Cloud Storage bucket. Reference must point to a child URL:

// Create a storage reference from our app

val storageRef = FirebaseStorage.getInstance().reference

// Create a reference to "javasampleapproach.jpg"

val jsaRef = storageRef.child("mountains.jpg")

// Create a reference to 'images/javasampleapproach.jpg'

val jsaImagesRef = storageRef.child("images/javasampleapproach.jpg")

If the file names are the same:

// true

mountainsRef.name == jsaImagesRef.name

// false

mountainsRef.path == jsaImagesRef.path

2. Upload Data using

2.1 putBytes()

val data: ByteArray = ...

fileRef.putBytes(data)

.addOnSuccessListener { taskSnapshot ->

// Uri: taskSnapshot.downloadUrl

// Name: taskSnapshot.metadata!!.name

// Path: taskSnapshot.metadata!!.path

// Size: taskSnapshot.metadata!!.sizeBytes

}

.addOnFailureListener { exception ->

// Handle unsuccessful uploads

}

.addOnProgressListener { taskSnapshot ->

// taskSnapshot.bytesTransferred

// taskSnapshot.totalByteCount

}

.addOnPausedListener { taskSnapshot ->

// Upload is paused

}

2.2 putFile()

val fileUri: Uri? = ...

fileRef.putFile(fileUri!!)

.addOnSuccessListener { taskSnapshot ->

// Uri: taskSnapshot.downloadUrl

// Name: taskSnapshot.metadata!!.name

// Path: taskSnapshot.metadata!!.path

// Size: taskSnapshot.metadata!!.sizeBytes

}

.addOnFailureListener { exception ->

// Handle unsuccessful uploads

}

.addOnProgressListener { taskSnapshot ->

// taskSnapshot.bytesTransferred

// taskSnapshot.totalByteCount

}

.addOnPausedListener { taskSnapshot ->

// Upload is paused

}

2.3 putStream()

val stream: InputStream = ...

fileRef.putStream(stream)

.addOnSuccessListener { taskSnapshot ->

// Uri: taskSnapshot.downloadUrl

// Name: taskSnapshot.metadata!!.name

// Path: taskSnapshot.metadata!!.path

// Size: taskSnapshot.metadata!!.sizeBytes

}

.addOnFailureListener { exception ->

// Handle unsuccessful uploads

}

.addOnProgressListener { taskSnapshot ->

// because this is a stream so: taskSnapshot.totalByteCount = -1 (always)

// taskSnapshot.bytesTransferred

}

.addOnPausedListener { taskSnapshot ->

// Upload is paused

}

3.4 Manage Uploads

We can pause, resume, or cancel upload process:

val uploadTask = fileRef.putFile(file) // putBytes() or putStream()

uploadTask.pause()

uploadTask.resume()

uploadTask.cancel()

II. Practice

1. Goal

We will build an Android App that can:
– create Account, sign in/sign out for Firebase Authentication.
– choose image from Gallery, then upload it to Firebase Cloud Storage using putBytes(), putStream() and putFile() methods.

kotlin-firebase-storage-upload-file-app-demo

2. Technology

– Gradle 3.0.1
– Android Studio 3.x
– Firebase Android SDK 11.x

3. Project Structure

kotlin-firebase-storage-upload-file-structure

LoginActivity is for Authentication, then user can change to StorageActivity to upload image to Firebase Cloud Storage.

4. Step by step

4.1 Create Android Project

– Generate new Android Project with package com.javasampleapproach.kotlin.firebase.storage.
– Follow steps to add Firebase Auth and Firebase Storage.

4.2 Enable Firebase Auth

Go to Your Firebase Project Console -> Authentication -> SIGN-IN METHOD -> Enable Email/Password.

4.3 LoginActivity

In this tutorial, we don’t explain way to authenticate an user again. To know how to implement Firebase Authentication App Client, please visit:
Kotlin Firebase Authentication – How to Sign Up, Sign In, Sign Out, Verify Email | Android

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:id="@+id/main_layout"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:weightSum="3">

<LinearLayout

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_weight="2"

android:gravity="center_horizontal"

android:orientation="vertical">

<TextView

android:id="@+id/tvTitle"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginBottom="16dp"

android:gravity="center"

android:text="grokonez.com"

android:textSize="28sp" />

<TextView

android:id="@+id/tvStatus"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="center"

android:padding="4dp"

android:text="Signed Out"

android:textSize="14sp" />

<TextView

android:id="@+id/tvDetail"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="center"

android:padding="4dp"

android:textSize="14sp"

tools:text="Firebase User ID: 123456789abc" />

</LinearLayout>

<RelativeLayout

android:layout_width="fill_parent"

android:layout_height="0dp"

android:layout_weight="1"

android:background="#E0E0E0"

android:gravity="center_vertical">

<LinearLayout

android:id="@+id/email_password_fields"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

android:paddingLeft="16dp"

android:paddingRight="16dp">

<EditText

android:id="@+id/edtEmail"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_weight="1"

android:hint="Email"

android:inputType="textEmailAddress" />

<EditText

android:id="@+id/edtPassword"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_weight="1"

android:hint="Password"

android:inputType="textPassword" />

</LinearLayout>

<LinearLayout

android:id="@+id/email_password_buttons"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_below="@+id/email_password_fields"

android:orientation="horizontal"

android:paddingLeft="16dp"

android:paddingRight="16dp">

<Button

android:id="@+id/btn_email_sign_in"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginLeft="4dp"

android:layout_marginRight="4dp"

android:layout_weight="1"

android:text="Sign In" />

<Button

android:id="@+id/btn_email_create_account"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginLeft="4dp"

android:layout_marginRight="4dp"

android:layout_weight="1"

android:text="Create Account" />

</LinearLayout>

<LinearLayout

android:id="@+id/layout_signed_in_buttons"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:orientation="horizontal"

android:paddingLeft="16dp"

android:paddingRight="16dp"

android:visibility="gone"

android:weightSum="2.0">

<Button

android:id="@+id/btn_sign_out"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginLeft="4dp"

android:layout_marginRight="4dp"

android:layout_weight="1.0"

android:text="Sign Out" />

<Button

android:id="@+id/btn_test_storage"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginLeft="4dp"

android:layout_marginRight="4dp"

android:layout_weight="1.0"

android:text="Test Storage" />

</LinearLayout>

</RelativeLayout>

</LinearLayout>

package com.javasampleapproach.kotlin.firebase.storage

import android.os.Bundle

import android.view.View

import kotlinx.android.synthetic.main.activity_login.*

import com.google.firebase.auth.FirebaseAuth

import com.google.firebase.auth.FirebaseUser

import android.widget.Toast

import android.util.Log

import android.text.TextUtils

import android.content.Intent

import android.support.v7.app.AppCompatActivity

class LoginActivity : AppCompatActivity(), View.OnClickListener {

private val TAG = "LoginActivity"

private var mAuth: FirebaseAuth? = null

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_login)

btn_email_sign_in.setOnClickListener(this)

btn_email_create_account.setOnClickListener(this)

btn_sign_out.setOnClickListener(this)

btn_test_storage.setOnClickListener(this)

mAuth = FirebaseAuth.getInstance()

}

override fun onStart() {

super.onStart()

val currentUser = mAuth!!.currentUser

updateUI(currentUser)

}

override fun onClick(view: View?) {

val i = view!!.id

when (i) {

R.id.btn_email_create_account -> createAccount(edtEmail.text.toString(), edtPassword.text.toString())

R.id.btn_email_sign_in -> signIn(edtEmail.text.toString(), edtPassword.text.toString())

R.id.btn_sign_out -> signOut()

R.id.btn_test_storage -> testStorage()

}

private fun createAccount(email: String, password: String) {

Log.e(TAG, "createAccount:" + email)

if (!validateForm(email, password)) {

return

}

mAuth!!.createUserWithEmailAndPassword(email, password)

.addOnCompleteListener(this) { task ->

if (task.isSuccessful) {

Log.e(TAG, "createAccount: Success!")

// update UI with the signed-in user's information

val user = mAuth!!.currentUser

updateUI(user)

} else {

Log.e(TAG, "createAccount: Fail!", task.exception)

Toast.makeText(applicationContext, "Authentication failed!", Toast.LENGTH_SHORT).show()

updateUI(null)

}

private fun signIn(email: String, password: String) {

Log.e(TAG, "signIn:" + email)

if (!validateForm(email, password)) {

return

}

mAuth!!.signInWithEmailAndPassword(email, password)

.addOnCompleteListener(this) { task ->

if (task.isSuccessful) {

Log.e(TAG, "signIn: Success!")

// update UI with the signed-in user's information

val user = mAuth!!.currentUser

updateUI(user)

} else {

Log.e(TAG, "signIn: Fail!", task.exception)

Toast.makeText(applicationContext, "Authentication failed!", Toast.LENGTH_SHORT).show()

updateUI(null)

}

if (!task.isSuccessful) {

tvStatus.text = "Authentication failed!"

}

private fun signOut() {

mAuth!!.signOut()

updateUI(null)

}

private fun validateForm(email: String, password: String): Boolean {

if (TextUtils.isEmpty(email)) {

Toast.makeText(applicationContext, "Enter email address!", Toast.LENGTH_SHORT).show()

return false

}

if (TextUtils.isEmpty(password)) {

Toast.makeText(applicationContext, "Enter password!", Toast.LENGTH_SHORT).show()

return false

}

if (password.length < 6) {

Toast.makeText(applicationContext, "Password too short, enter minimum 6 characters!", Toast.LENGTH_SHORT).show()

return false

}

return true

}

private fun updateUI(user: FirebaseUser?) {

if (user != null) {

tvStatus.text = "User Email: " + user.email

tvDetail.text = "Firebase User ID: " + user.uid

email_password_buttons.visibility = View.GONE

email_password_fields.visibility = View.GONE

layout_signed_in_buttons.visibility = View.VISIBLE

} else {

tvStatus.text = "Signed Out"

tvDetail.text = null

email_password_buttons.visibility = View.VISIBLE

email_password_fields.visibility = View.VISIBLE

layout_signed_in_buttons.visibility = View.GONE

}

private fun testStorage() {

startActivity(Intent(this, StorageActivity::class.java))

}

4.4 StorageActivity

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:paddingLeft="16dp"

android:paddingRight="16dp">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center"

android:text="grokonez.com"

android:textSize="20sp" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:weightSum="3">

<Button

android:id="@+id/btn_choose_file"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Choose File" />

<EditText

android:id="@+id/edtFileName"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="2"

android:hint="File Name" />

</LinearLayout>

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="16dp"

android:layout_marginTop="16dp"

android:text="Upload using:"

android:textSize="18sp" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:weightSum="3">

<Button

android:id="@+id/btn_upload_byte"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Bytes" />

<Button

android:id="@+id/btn_upload_file"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="File" />

<Button

android:id="@+id/btn_upload_stream"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Stream" />

</LinearLayout>

<TextView

android:id="@+id/tvFileName"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:layout_margin="5dp"

android:text="File Name" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:weightSum="5">

<ImageView

android:id="@+id/imgFile"

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_weight="4.7" />

<Button

android:id="@+id/btn_back"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="Back" />

</LinearLayout>

package com.javasampleapproach.kotlin.firebase.storage

import android.content.Intent

import android.graphics.Bitmap

import android.net.Uri

import android.provider.MediaStore

import android.support.v7.app.AppCompatActivity

import android.os.Bundle

import kotlinx.android.synthetic.main.activity_storage.*

import android.text.TextUtils

import android.util.Log

import android.view.View

import android.webkit.MimeTypeMap

import android.widget.*

import com.google.firebase.storage.FirebaseStorage

import com.google.firebase.storage.StorageReference

import java.io.ByteArrayOutputStream

import java.io.FileNotFoundException

import java.io.IOException

import java.io.InputStream

class StorageActivity : AppCompatActivity(), View.OnClickListener {

private val TAG = "StorageActivity"

//track Choosing Image Intent

private val CHOOSING_IMAGE_REQUEST = 1234

private var fileUri: Uri? = null

private var bitmap: Bitmap? = null

private var imageReference: StorageReference? = null

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_storage)

tvFileName.text = ""

imageReference = FirebaseStorage.getInstance().reference.child("images")

btn_choose_file.setOnClickListener(this)

btn_upload_byte.setOnClickListener(this)

btn_upload_file.setOnClickListener(this)

btn_upload_stream.setOnClickListener(this)

btn_back.setOnClickListener(this)

}

override fun onClick(view: View?) {

val i = view!!.id

when (i) {

R.id.btn_choose_file -> showChoosingFile()

R.id.btn_upload_byte -> uploadBytes()

R.id.btn_upload_file -> uploadFile()

R.id.btn_upload_stream -> uploadStream()

R.id.btn_back -> finish()

}

private fun uploadBytes() {

if (fileUri != null) {

val fileName = edtFileName.text.toString()

if (!validateInputFileName(fileName)) {

return

}

val baos = ByteArrayOutputStream()

bitmap!!.compress(Bitmap.CompressFormat.JPEG, 50, baos)

val data: ByteArray = baos.toByteArray()

val fileRef = imageReference!!.child(fileName + "." + getFileExtension(fileUri!!))

fileRef.putBytes(data)

.addOnSuccessListener { taskSnapshot ->

Log.e(TAG, "Uri: " + taskSnapshot.downloadUrl)

Log.e(TAG, "Name: " + taskSnapshot.metadata!!.name)

tvFileName.text = taskSnapshot.metadata!!.path + " - " + taskSnapshot.metadata!!.sizeBytes / 1024 + " KBs"

Toast.makeText(this, "File Uploaded ", Toast.LENGTH_LONG).show()

}

.addOnFailureListener { exception ->

Toast.makeText(this, exception.message, Toast.LENGTH_LONG).show()

}

.addOnProgressListener { taskSnapshot ->

// progress percentage

val progress = 100.0 * taskSnapshot.bytesTransferred / taskSnapshot.totalByteCount

// percentage in progress dialog

val intProgress = progress.toInt()

tvFileName.text = "Uploaded " + intProgress + "%..."

}

.addOnPausedListener { System.out.println("Upload is paused!") }

} else {

Toast.makeText(this, "No File!", Toast.LENGTH_LONG).show()

}

private fun uploadFile() {

if (fileUri != null) {

val fileName = edtFileName.text.toString()

if (!validateInputFileName(fileName)) {

return

}

val fileRef = imageReference!!.child(fileName + "." + getFileExtension(fileUri!!))

fileRef.putFile(fileUri!!)

.addOnSuccessListener { taskSnapshot ->

Log.e(TAG, "Uri: " + taskSnapshot.downloadUrl)

Log.e(TAG, "Name: " + taskSnapshot.metadata!!.name)

tvFileName.text = taskSnapshot.metadata!!.path + " - " + taskSnapshot.metadata!!.sizeBytes / 1024 + " KBs"

Toast.makeText(this, "File Uploaded ", Toast.LENGTH_LONG).show()

}

.addOnFailureListener { exception ->

Toast.makeText(this, exception.message, Toast.LENGTH_LONG).show()

}

.addOnProgressListener { taskSnapshot ->

// progress percentage

val progress = 100.0 * taskSnapshot.bytesTransferred / taskSnapshot.totalByteCount

// percentage in progress dialog

val intProgress = progress.toInt()

tvFileName.text = "Uploaded " + intProgress + "%..."

}

.addOnPausedListener { System.out.println("Upload is paused!") }

} else {

Toast.makeText(this, "No File!", Toast.LENGTH_LONG).show()

}

private fun uploadStream() {

if (fileUri != null) {

val fileName = edtFileName.text.toString()

if (!validateInputFileName(fileName)) {

return

}

try {

val stream: InputStream = contentResolver.openInputStream(fileUri)

val fileRef = imageReference!!.child(fileName + "." + getFileExtension(fileUri!!))

fileRef.putStream(stream)

.addOnSuccessListener { taskSnapshot ->

Log.e(TAG, "Uri: " + taskSnapshot.downloadUrl)

Log.e(TAG, "Name: " + taskSnapshot.metadata!!.name)

tvFileName.text = taskSnapshot.metadata!!.path + " - " + taskSnapshot.metadata!!.sizeBytes / 1024 + " KBs"

Toast.makeText(this, "File Uploaded ", Toast.LENGTH_LONG).show()

}

.addOnFailureListener { exception ->

Toast.makeText(this, exception.message, Toast.LENGTH_LONG).show()

}

.addOnProgressListener { taskSnapshot ->

// because this is a stream so:

// taskSnapshot.getTotalByteCount() = -1 (always)

tvFileName.text = "Uploaded " + taskSnapshot.bytesTransferred + " Bytes..."

}

.addOnPausedListener { System.out.println("Upload is paused!") }

} catch (e: FileNotFoundException) {

e.printStackTrace()

}

} else {

Toast.makeText(this, "No File!", Toast.LENGTH_LONG).show()

}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {

super.onActivityResult(requestCode, resultCode, data)

if (bitmap != null) {

bitmap!!.recycle()

}

if (requestCode == CHOOSING_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.data != null) {

fileUri = data.data

try {

bitmap = MediaStore.Images.Media.getBitmap(contentResolver, fileUri)

imgFile.setImageBitmap(bitmap)

} catch (e: IOException) {

e.printStackTrace()

}

private fun showChoosingFile() {

val intent = Intent()

intent.type = "image/*"

intent.action = Intent.ACTION_GET_CONTENT

startActivityForResult(Intent.createChooser(intent, "Select Image"), CHOOSING_IMAGE_REQUEST)

}

private fun getFileExtension(uri: Uri): String {

val contentResolver = contentResolver

val mime = MimeTypeMap.getSingleton()

return mime.getExtensionFromMimeType(contentResolver.getType(uri))

}

private fun validateInputFileName(fileName: String): Boolean {

if (TextUtils.isEmpty(fileName)) {

Toast.makeText(this, "Enter file name!", Toast.LENGTH_SHORT).show()

return false

}

return true

}

4.5 Android Manifest

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.javasampleapproach.kotlin.firebase.storage">

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

4.6 Run & Check result

– Use Android Studio, build and Run your Android App:

kotlin-firebase-storage-upload-file-app-demo

– Open Firebase Project Console -> Storage:
kotlin-firebase-storage-upload-file-result-console

III. Source code

Kotlin-FirebaseStorage-upload-data

By grokonez | December 22, 2017.

Last updated on July 13, 2018.

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I. How to upload file

0. Add Firebase to Android App

0.1 Add Firebase Storage

0.2 Add Firebase Auth

0.3 Check

1. Create a Reference

2. Upload Data using

2.1 putBytes()

2.2 putFile()

2.3 putStream()

3.4 Manage Uploads

II. Practice

1. Goal

2. Technology

3. Project Structure

4. Step by step

4.1 Create Android Project

4.2 Enable Firebase Auth

4.3 LoginActivity

4.4 StorageActivity

4.5 Android Manifest

4.6 Run & Check result

III. Source code

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