So I setup email/password register and login.
That is working. I thought Firebase took care of this but apparently not.
I want, after the user closes the app, to be logged in already next time they open the app.
What is missing?
class LoginActivity : AppCompatActivity(){
lateinit var auth: FirebaseAuth
lateinit var user: FirebaseAuth
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_login)
auth = FirebaseAuth.getInstance()
}
fun loginLoginClicked(view: View) {
// Perform login
val email = loginEmailTxt.text.toString()
val password = loginPasswordTxt.text.toString()
auth.signInWithEmailAndPassword(email, password)
.addOnSuccessListener {
finish()
}
.addOnFailureListener { exception ->
Log.e("Exception", "Could not sign in user - ${exception.localizedMessage}")
}
val loginIntent = Intent(this, MainActivity::class.java)
startActivity(loginIntent)
}
fun loginCreateClicked(view: View) {
// segue to the create user activity
val createIntent = Intent(this, SignUpActivity::class.java)
startActivity(createIntent)
}}
}
Firebase Authentication does automatically remember authentication state, so the user will still be authenticated when the app is restarted.
However, if your LoginActivity is the launcher activity, you'll still land on this activity, so you'll need to check whether the user is authenticated in onCreate(), and then redirect them to your MainActivity if they are already logged in, something like:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
auth = FirebaseAuth.getInstance();
if (auth.getCurrentUser() != null) {
// User is signed in (getCurrentUser() will be null if not signed in)
val intent = Intent(this, MainActivity::class.java);
startActivity(intent);
finish();
}
}
This makes use of the FirebaseAuth#getCurrentUser() method that will return a FirebaseUser object if the user is logged in, or null if they are not logged in.
Alternatively, you could swap it around so that the MainActivity is the launcher activity and then only show your LoginActivity if the user is not logged in.
....
If anyone landing up here for achieving same thing using Java then use following code (credit to Grimthorr's answer for the Kotlin version that this is a port of)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
auth = FirebaseAuth.getInstance();
if (auth.getCurrentUser() != null) {
// User is signed in (getCurrentUser() will be null if not signed in)
Intent intent = Intent(this, MainActivity.class);
startActivity(intent);
finish();
// or do some other stuff that you want to do
}
Related
Can someone explain to me why this simple code is not working properly?
In the beginning I created an object with auth and currentUser
object FirebaseUtils {
val auth: FirebaseAuth = FirebaseAuth.getInstance()
val currentUser: FirebaseUser? = auth.currentUser
}
My login activity function
fun login(){
val email = binding.loginInput.text.toString()
val password = binding.passwordInput.text.toString()
auth.signInWithEmailAndPassword(email, password)
.addOnCompleteListener {
task ->
if (task.isSuccessful){
task.result
Log.d("login_status", "Logged: ${currentUser?.uid}")
startActivity(Intent(this, MainActivity::class.java))
finish()
} else {
Log.d("login_status", task.exception.toString())
}
}
}
Start activity:
lifecycleScope.launch {
delay(2000)
if(currentUser?.uid != null){
Log.d("login_status", "Logged: ${currentUser.uid}")
startActivity(Intent(applicationContext, MainActivity::class.java))
}else{
startActivity(Intent(applicationContext, LoginMainActivity::class.java))
}
finish()
}
And sign out
fun signOut(){
auth.signOut()
startActivity(Intent(this, LoginMainActivity::class.java))
Log.d("login_status", "Signed out: ${currentUser?.uid}")
finish()
}
The problem is that after the first login I can see that logged user is null so my app is crashing (no data for the user). However, after restarting I am logged in as this user. I cant also sign out - activity changes to the login screen but even if I pass different credentials the user remains the same.
EDIT
When I log in and restart the app it works - the correct user is logged.
When I log out and restart the app it also works - the user is signed out.
So why is there a problem between activities
Your result is null because you are getting the result object out of the task object but you aren't doing anything with it. Simply calling:
task.result
Doesn't provide any benefit. However, you can save that result into a variable and call AuthResult#getUser() like this:
val user = task.result.getUser()
Log.d("login_status", "Logged: ${user?.uid}")
So right after you authenticate the user successfully, you'll be able to log the UID correctly.
I use SharedPreferences to stay logged in, and it works, but when I use it with Firebase the code doesn't work, I don't know if with firebase shared preferences doesn't work for staying logged in, or what I should do, I'm new with android studio and I search in youtube but I can't find how to stay logged in with firebase using Kotlin
Added code sample
For Firebase:
logInButton.setOnClickListener {
if(emailEditText.text.isNotEmpty() && passwordEditText.text.isNotEmpty()){
FirebaseAuth.getInstance()
.signInWithEmailAndPassword(emailEditText.text.toString()
,passwordEditText.text.toString()).addOnCompleteListener {
if(it.isSuccessful){
showHome(it.result?.user?.email?:"",ProviderType.BASIC)
}else{
showAlert()
}
}
}
}
private fun showAlert(){
val builder= AlertDialog.Builder(this)
builder.setTitle("Error")
builder.setMessage("Error")
builder.setPositiveButton("Accept",null)
val dialog:AlertDialog=builder.create()
dialog.show()
}
private fun showHome(email:String,provider:ProviderType){
val homeIntent= Intent(this,Menu::class.java).apply{
putExtra("email",email)
putExtra("provider",provider.name)
}
startActivity(homeIntent)
}
For shared preferences
private lateinit var sharedPreferences: SharedPreferences
var isRemember=false
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
sharedPreferences = getSharedPreferences("SHARED_PREF", Context.MODE_PRIVATE)
isRemember=sharedPreferences.getBoolean("CHECKBOX",false )
if (isRemember){
val intent= Intent(this,Menu::class.java)
startActivity(intent)
finish()
}
fun checkUserValues(){
}
logInButton.setOnClickListener {
val email: String =emailEditText.text.toString()
val password: String = passwordEditText.text.toString()
val checked:Boolean = check_remember.isChecked
val editor : SharedPreferences.Editor = sharedPreferences.edit()
editor.putString("EMAIL",email)
editor.putString("PASSWORD",password)
editor.putBoolean("CHECKBOX",checked)
editor.apply()
Toast.makeText(this, "Logged in save",Toast.LENGTH_LONG).show()
val intent=Intent(this,Menu::class.java)
startActivity(intent)
finish()
}
}
Much appreciated.
I use shared preferences to stay logged in,
Firebase already stores the user credentials and restores them when the user restarts the app. There is no code you need to write for this, as saving the data happens automatically when the user first signs in, and the information is then restored, when the user starts the app again.
I recommend removing the code where you persist the credentials to shared preferences, and leave that to Firebase.
I'm still new to Kotlin and Android and developing a project that uses shared preferences.
I have multiple Activities and a user must be logged in to use all functions of the Main Activity.
The Main Acitivity has a menu drawer with few menu items. The first one is redirecting user to Login Activity. The rest of the menu items are hidden until user is logged in.
The process is as follows:
Start with Main Activity -> The application checks if the user is logged in -> If not you must log in -> Go to Login Activity -> Logging in -> Then go back to Main Activity.
However, the main activity does not refresh at all. I mean, I don't even know how to do it. I want my main activity to refresh when I return from login activity.
So far, it only works when I close the app and reopen it. The session is likely cached in Shared preferences.
I tried to start and finish Activites by clicking certain buttons (eg After clicking login button when user passed all credentials) but it didn't work.
The following code checks that the user is logged in when the main activity starts
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val menu: Menu = navView.menu
val target2: MenuItem = menu.findItem(R.id.miItem2)
val target3: MenuItem = menu.findItem(R.id.miItem3)
//region user session
try{
if(!SharedPrefManager.getInstance(this)!!.isLoggedIn()){
target2.isVisible = false
target3.isVisible = false
Toast.makeText(applicationContext, "nie zalogowany", Toast.LENGTH_LONG).show()
}
else{
target2.isVisible = true
target3.isVisible = true
Toast.makeText(applicationContext, "zalogowany", Toast.LENGTH_LONG).show()
}
}catch (e: NullPointerException){
}
//endregion
And there is function isLoggedIn():
fun isLoggedIn(): Boolean{
val sharedPreferences: SharedPreferences = mCtx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
if(sharedPreferences.getString(KEY_USER_EMAIL, null) != null){
return true
}
return false
}
This code below takes me to the Login Activity
val btnLogInActivity : Button = findViewById(R.id.logButton)
btnLogInActivity.setOnClickListener {
val intent = Intent(this, LoginActivity::class.java)
startActivity(intent)
}
And this is the code in Login Activity (userLogin function is not important in this context):
buttonLogin.setOnClickListener {
userLogin()
newMainActivity()
}
private fun newMainActivity(){
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
}
Ps. If you need more code to fix the problem, let me know
You just have to add finish() in your code. Update your methods with the code below:
btnLogInActivity.setOnClickListener {
val intent = Intent(this, LoginActivity::class.java)
startActivity(intent)
finish()
}
And after login:
private fun newMainActivity(){
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
finish()
}
Let me describe the application im trying to do using Kotlin, on Android Studio.
Splash Screen => Login Screen => Main App
Splash Screen: Just a photo
Login Screen: Provides different ways of logging (Google, Facebook, etc)
MainActivity: Allows you to log off, in that case, you must return to "Login Screen"
So far I have been working only with Facebook Login.
I managed to place the button, make it work, and get a proper uid. The trouble is that, when that button is clicked, it automatically switches to "Log Out". So, when I go back from my MainActivity to my Login Screen, instead of having the button to Login again, im having a "Log Out" button, when account is actually already logged out.
Is there a way to prevent this button from changing? I have been reading tons of documentation, but havent found anything useful.
Is my idea incorrect? Or is there a better way to do this?
Note that everytime I Leave the LoginScreen, I place a finish(). The reason of this was to try to reset the activity, and make it work as if the program was running from scratch.
Variables defined on LoginScreen
private var mCallBackManager : CallbackManager?= null
private var mFirebaseAuth : FirebaseAuth?= null
On create function
override fun onCreate(savedInstanceState: Bundle?)
{
super.onCreate(savedInstanceState)
setContentView(R.layout.lay_login_screen)
//-----------Inicializadores-Facebook---------------
mFirebaseAuth = FirebaseAuth.getInstance()
FacebookSdk.sdkInitialize(getApplicationContext())
mCallBackManager = CallbackManager.Factory.create()
//--------------------------------------------------
//-----------Boton-Facebook-------------------------
Button_LoginScreen_LoginFace.setOnClickListener()
{
iniciarSesionFacebook();
}
//--------------------------------------------------
}
private fun iniciarSesionFacebook()
{
Button_LoginScreen_LoginFace.registerCallback(mCallBackManager, object : FacebookCallback<LoginResult>
{
override fun onSuccess(result: LoginResult?)
{
d(getString(R.string.TAG_FacebookLogin),"Login Correct")
handleFacebookToken(result!!.accessToken)
}
override fun onCancel()
{
d(getString(R.string.TAG_FacebookLogin),"Login cancelled")
}
override fun onError(error: FacebookException?)
{
d(getString(R.string.TAG_FacebookLogin),"Login Error")
}
})
}
private fun handleFacebookToken(accessToken: AccessToken?)
{
val credential = FacebookAuthProvider.getCredential(accessToken!!.token)
mFirebaseAuth!!.signInWithCredential(credential).addOnFailureListener()
{error->
d(getString(R.string.TAG_FacebookLogin),"Error 1"+error.message)
}
.addOnSuccessListener { resultado->
startActivity(Intent(this, MainActivity::class.java))
finish()
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?)
{
super.onActivityResult(requestCode, resultCode, data)
mCallBackManager!!.onActivityResult(requestCode,resultCode,data)
}
Finally, this is how I "Log Out" from MainActivity, and return to LoginScreen
class MainActivity : AppCompatActivity()
{
//----------Variables-Globales----------------
private var mFirebaseAuth : FirebaseAuth?= null
//--------------------------------------------
override fun onCreate(savedInstanceState: Bundle?)
{
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
//-------Inicializo-Variables------------------------
mFirebaseAuth = FirebaseAuth.getInstance()
//---------------------------------------------------
Button_MainActity_LogOf.setOnClickListener{
val firebaseaux=mFirebaseAuth
firebaseaux?.signOut()
startActivity(Intent(this, ActivityLoginScreen::class.java))
}
}
}
This is how the LoginScreen looks the first time is ran.
This is how it looks after manually logging of. Note that is not only the appearence of the code, the code itself changes. Now the button doesnt allow you to LogIn.
Just to add some extra information, i have found this property on the docs
Configuration: auto_logout_link
HTML5 Attribute: data-auto-logout-link
Description: If its activated, the button will be replaced by a LogOut button if the user has already logged in
Options: True,False
This es EXACTLY what im looking for. But, from what I can see, that is only ment for webpages and not android. Does somebody know how to touch this configuration in android? or the equivalent adroid option?
I will add the link where I found the property.
https://developers.facebook.com/docs/facebook-login/web/login-button/
Thanks in advance
Ok, after some time I managed to solve the Issue.
I was logging out from the Firebase Authentication, but not from Facebook authentication.
I didnt manage to stop the button from behaving like it does, but at least the behaviour now is correct.
I will share my new LogOut code.
Button_MainActity_LogOf.setOnClickListener{
FirebaseAuth.getInstance().signOut() //Log out from Firebase
if(isFacebookLogin()) //Check if logged in on facebook
{
LoginManager.getInstance().logOut() //Log out from facebook
}
//Here i should log out from other providers
startActivity(Intent(this, ActivityLoginScreen::class.java))
}
private fun isFacebookLogin(): Boolean
{
return AccessToken.getCurrentAccessToken() !=null
}
So I try to create Sign-out button in a fragment Home but, everytime user SignOut, the app will crash and it caused by document snapshot.
this is my document snapshot code.
private fun loadProfile() {
val user = mAuth!!.currentUser
if (user != null) {
...//loading profile code
}
val uid = user.uid
documentReference = db!!.collection("users").document(uid)
documentReference!!.addSnapshotListener { documentSnapshot, e ->
//this if returning null after user signout
if (documentSnapshot!!.exists()) {
if (documentSnapshot.get(KEY_HP) != null) {
...//loading profile code
}else {
val intent = Intent(this#Home.activity, LoginActivity::class.java)
startActivity(intent)
}
}
} else {
val intent = Intent(this#Home.activity, LoginActivity::class.java)
startActivity(intent)
}
}
as you can see I desperately add else everywhere but that does not help.
this is my Sign-out method
private fun signOut() {
mAuth!!.signOut()
val intent = Intent(this#Home.activity, LoginActivity::class.java)
startActivity(intent)
}
So, I need to properly signout without the app being crash
FirebaseAuth.getInstance().signOut();
Use this to signout from Firebase. And then, if you try to perform any action of a logged in user, you won't be able to, you will have to login again.
FUTURE REFERENCE
After fighting with the "sign-out" method for a couple days, I realized that if you have snapshot listeners attached within the activity, make sure you handle and return the error, as stated here, or else you may run into some Permission Errors and crashes.