Simple Login App Using Database (PART 4) - Implementing Logout Activity! (Android Studio 3.0)

[@ProfessorDK]

The app and code in the video are tested and perfectly working. However, I have seen that some of you are facing difficulties and getting some errors, so here is a beginners guide to debugging: 1) Error: Null object reference Solution: This always means you have given the wrong XML ID, just correct it 2) Error: User Credentials not sent to Firebase Solution: Check if you have added all dependencies else do the following: In Android Studio, go to Tools > Firebase. Click on it. A new tab will open. Click on Authentication > More Info > Email and Password Authentication Link. Another tab will open. Check if the first step shows connected to the database. If not, just click on it and you should be asked for Firebase credentials and on entering that, you will get connected :) 3) Error: App is crashing Solution: Check your logcat section present at the bottom of Android Studio, it will tell you where you have made the error or what caused the error. Just go to that line then and debug. 4) Error: App crashing in emulator: This happens because your emulator doesn't have the latest google play store services. Either update play store or just run it on normal phone Also, some things to note: 1) Every new user must have unique email ID 2) The password length must be more than 8 characters long 3) Internet must be ON Hope this helped everyone :)

[@svidu96]

Though this video series are 2 years old, I could manage to create the app using this tutorial. There are few changes in Android studio and the Google Firebase now but almost all the functions are still working :) Thank you

[@whacker4321]

I have to say that the videos are super helpful, and my college lectures are so bad. You are my superman !!! saving my day !!! Thank you !!!!

[@edpdul707]

Professor, you are great! your videos are very detail oriented. We the learners appreciate your effort and dedication.

[@saivarshith1387]

Hello sir, one thing I would like to say is ur teaching is excellent.I am following ur videos. My humble request is please don't stop doing such useful stuff to all viewer's....

[@ProfessorDK]

Do not worry, not stopping anytime soon :)

[@saivarshith1387]

Sir, how can I prevent the user from registerActivity to loginActivity when we press back after login....after successful login I am pressing back then it is starting to go to login activity...help me

[@ProfessorDK]

+sai varshith Use the finish() to destroy your login activity.

[@SastaTrader]

How do u get to know about so many methods and syntaxes in android studio? Should we buy books to? Or just these videos would do?

[@pranjalkhandelwal759]

Best Video i have ever watched on android studio

[@souravbasu5314]

man u are very good ..just keep up the good work and please if possibe make real time ride sharing services like ola and uber using mordern ui ..it would be be very helpful...so that people can learn the new tecchniuws like dagger ,dao ....

[@aselfmuser9210]

you are awesome sir.. just the video i needed.. great job

[@actoraareesh]

Hii sir, How i can build Only one time Login and after i can go to MainActivity? In Android Studio! Pls give a answer sir....

[@kierancarter3693]

amazing teacher bro please keep it up, you've helped me so much

[@umedrajawat8937]

can u upload a video of how to get the databse data displayed on the navigation menu?

[@ProfessorDK]

Sure will do :)

[@jasemalshehhi3691]

?in 10:50 app replaced with what in the newest version

[@tarungoyal6526]

Sir these all tutorials are awesome for Android... But please suggest some source from which Android app development can be studied from beginner level.. Thank you

[@len5120]

sir all your tutorial are awesome with proper explaining for each step Sir , if possible please give a complete tutorial on developing an app like 1mg app,food order app.

[@ProfessorDK]

+lenin singh Once I finish the beginner series i have a lot of practical app designs lined up. So stay tuned :)

[@yopiyowwwxfbfpfk]

waahh , i hope so too, we have a project and its all about a food order app. but we're still lacking a lot(our prof doesnt teach us the codes or how to or what will happen if we did this or that) huhu

[@muhammadzaheersajid9396]

if you use latest android 3.1.2 so alt+0 not working you can use ctrl+o its working so guys if on your android studio alt+0 not working you can use ctrl+o thnx

[@ProfessorDK]

CTRL + insert also can be used.

[@muhammadzaheersajid9396]

yap right thnx

[@muhammadzaheersajid9396]

bro can you make tutorial of all like with sql lite??

[@jdcoding1012]

try alt + insert

[@rcpangeran]

Thank you..

[@DiscoverLivelife]

Great to see that menu bar functionality and logout As well.. I have query about how do we register through mobile number instead of email id and verified as well?? Any idea?

[@ProfessorDK]

+DiscoverLivelife I'll be covering email verification in next video and in the consecutive video I'll cover two step verification using mobile phone. So I guess that will help you with what u want :)

[@akshaykhamkar6685]

Sir this is great for me... I want video on how to generate report using database data as PDF format

[@younginsong4355]

What can you do insert to database when user login and logout time?

[@denniswambua4471]

Can python be linked with java to communicate with each other?

[@vpp1998]

Hi, your videos are really helpful. I want to add an admin account. If I input the email and password of the admin account then a different activity should open and for other accounts another activity. How do I do that?

[@pranaybhatia707]

you can create a new admin activity and use if condition to compare username string and password string to that of admins and direct it towards that activity.

[@gauravmasand]

Sir thank you so much for your efforts

[@SazSoft]

Sir, please also do the video for "Logout with retrofit"

[@rockquelgajilomo1042]

at 13:00 alt + 0 is not working for me. Can i know why? thanks ^^

[@ProfessorDK]

Check if your num lock is ON.

[@rockquelgajilomo1042]

im just using a laptop with no numpad ^^

[@archy-x]

Just go to the top left and click Code and then click Override methods

[@saniyabagwan3900]

Menu items not see in app please give me suggestion what to do

[@haru_bae]

Hello, i can't go to main activities, how should i do? Can you help me?

[@marvihsgroup5144]

Your Tutorial Is very supportive & its Absolutely Good For Beginner as well, but i am facing 2 problem which i mention below ! 1st - when i create the update profile & Change Password Activity i will stop receiving email verification & password reset link. 2nd - when i removed the both activities (profile update & change password) login and logout is successful, but second time when i login the logout from menu is crashing the application again and again. Please Help me out in this.

[@jdcoding1012]

Professor DK, I have been following your simple login app tutorial up until now and I can say that my app is working properly. But, may I know if it is possible to add database on firebase with Registered Users Table that consists of id, email, password and user type. And when the user Logged in, it will check the user type, If it is an admin or just an ordinary user and then it goes to different activities. Admin goes to admin profile activity and Ordinary user goes to its own profile activity Sorry for asking, I am new to firebase. Anyway, Thank you, I enjoy learning from you.

[@ProfessorDK]

I got your question, will implement it in upcoming videos. Stay tuned :)

[@kiranck4076]

can u tell me how to write the code if my logout button is on navigation drawer??

[@kinghafiez1305]

I gotta problem when i succesfully register, it directly go to second activity page instead of login page. So hmmm can u help me?

[@rwill.7313]

You can go to Settings on your phone (if you are using that), and go to the App info and Clear All Data. That will let you log in again. However, once you are logged in, it will automatically direct you to the second activity. Also, if you add the "Logout" buttons as described in this video, you can logout without clearing app data. I hope this helped.

[@TheBimalbhattarai]

iam facing the same problem...anyone help?

[@TheBimalbhattarai]

we are not talking about that...... we are saying that,,,,after signup..instead of going login screen..its driectly went to 3rd screen. i.e (that page which come after login) .

[@AngelineR]

@@TheBimalbhattarai How did you fix that?? Thanks!!!!

[@AngelineR]

Hey, did you fix it? Can you share the solution? Thanks!!!

[@bilalgurani8328]

if clicked the back button in my phone it goes to login activity and logout button is not working

[@ashutoshmishra1787]

My application is not able launch properly after installing through usb it start the activity and then automatically closed. In logcat the error shown is set status icon wrong theme

[@sadisusalisu216]

Thank you very much Professor, Please I am trying to use Navigation the one that is automatically generated by android studio how can I put the Logout on that? Thank you.

[@ProfessorDK]

Just add a menu to that and link your logout function to that :)

[@ezhilarasan2127]

Why you didn't use Logcat function like this Log.d(TAG, "------------------on create"); Its very useful for easily understand the code while running the application

[@abdessamadbaahmed8930]

sir it does not work for me they tell me to use android:showasaction .insted of app what shall i do?

[@puputsampurnia9654]

i want to ask you why getMenuInflater().inflate(R.menu.menu, menu); and the menu is eror shown that the res/menu is undetected, when i want to re-create new menu is also shown that the menu.xml is alredy exist. please help me, i don't know how to fix this

[@wardazain3644]

how impliment logout in navigation drawer sir

[@Mdirfan-lk1wx]

Sir when I try to login it shows login failed

[@ProfessorDK]

Post your logcat error

[@Mdirfan-lk1wx]

Sir my problem has been resolved after I watching video again

[@247killer9]

Can you add admin panel to control all users

[@mahanthiprudhvitej2678]

Nothing much to say ..... Just one Word ... Fucking Awesome ...! You are the man boss.... Great explanation ..... ! Thank You very much sir ...

[@ProfessorDK]

+Kristik Vlogs Glad you liked it :)

[@venkateshkumar5284]

i need how to create channel from one user to another user like whatsupp app! excellent video

[@muhammadamirulaizatmohdros4118]

Hi, I got a Java compiler error, which stated that I failed to link with file resources. How can I resolve this?

[@sandeepvarma6098]

Hi, how to pass logout in navigation drawer I tried to do that but the app keeps crashing please help me out.!

[@khalidzidan1522]

Hello. Can you please tell us how to view user passwords on firebase console?

[@ashishshrivastava9966]

Hi....I am observing one thing that without implementing logout button if I am pressing "back/return" button in my android mobile , I am directed to previous page I was in. If i want to avoid this, whether its possible....For eg. If i am in main activity and through login button i am directed to second activity and in the second activity if i press "back/return" button in my mobile it should not go to main activity. If it has to go it should be via logout button only and not through any other means.

[@ProfessorDK]

Yes, after login do finish() before the Intent. And when u click logout add an intent to login activity. The finish function destroys the activity we don't want to return to :)

[@ashishshrivastava9966]

Professor DK you mean to say inside the login.onclicklistener I need to do finish() or inside the validate function I need to do that....

[@ProfessorDK]

Do it before wherever u implimented the Intent.

[@moussanasreddine]

The tutorials are awesome, but in the login activity when the text fields are empty the app will crash, is there an easy way to fix it?

[@incdev6190]

Copy validate() method from Registration.activity and implement it the same way in Your Login.Activity

[@muhammadirfankurniawan9891]

Awesome tutorial sir! But can you please make a video how to create a crud application with firebase sir?

[@ProfessorDK]

+Muhammad Irfan Kurniawan Will make it soon. I have like a work plan set up. So I will make it along the way :=

[@sandeepjoshi395]

My emulator not working then how i connect app with database by running app in my phone

[@AshrafKhan-nb8od]

when I'm clicking the logout button in the toolbar app is crashing

[@yashrajghodke7211]

Sir when i click on logout button it works but...when i click on logout in menu it doesn't work

[@IgnitionPoint]

Sir plz make a video for navigation drawer and show details from firebase

[@AshrafKhan-nb8od]

Getting this error java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.firebase.auth.FirebaseAuth.signOut()' on a null object reference

[@gnaneshgn8341]

after clicking logout its not taking me to MainActivity...please help..ivedone the same as above

[@incdev6190]

It will take You to Activity that You have in Your first "IF" statement in Your Login.activity. after You register user is immediately Signed In, so when Your "IF" statement checks it - it close current activity and opens the one You set in startActivity. I have the same problem :) trying to figure it out now. ;)

[@nimanthakumara9479]

Super

[@srt2431]

It is not showing Menue On the screen

[@hrishii.02]

How to add Bottom Navigation?

[@hariprasad5252]

My app is closing out when I tried to login from mainActivity

[@vishalbhatane1608]

Thank you very much !

[@gauravdumre]

Sir.. How do I solve google play service error... plz guide

[@GBeRecordings]

Sir, please also do the video for "Forget Pasword"

[@avinashmakhija3592]

While login after signup my app is showing that login failed email address is already in use by another account... Sir, please give me solution as soon as possible......

[@KishoreKumar-ik1pp]

Hi DK, does this app works without internet once after complete development?

[@ProfessorDK]

No, since you are connected to a database, it will try to retrieve login details. If you aren't connected, it cannot do so and app won't work as expected.

[@shakibkhan7195]

Can u help how to add user information to data base and how to retrieve it

[@ProfessorDK]

Will be doing this topic in part 7 of login app using database series! Will be out soon :)

[@josedanielcontrerasperez8125]

Thank you I learn much

[@jakegavilanes9329]

I accidentally saved current state, then i tried logging in without password. Now login button is disabled. When I'm running the program, it kept showing me the saved current state which is the button login is disabled. How can I run the new state? Please help ASAP!

[@johnzee2274]

alt +0 is not working for me. I'm using windows 10. I wrote the code manually but it's showing error. How can i sort it out? thanks

[@ProfessorDK]

+John zee Your NumLock might be ON

[@johnzee2274]

Yeah that was the prob, thank you so much

[@kingkhan3161]

Yeah I think it's better alt+insert than alt+0

[@arunkumarkabilan2713]

I'm in love with android just because of you !! You teach so clearly and effectively..!! And I've many doubts in gradle files.. What are they?? Why are they?? Can you do videos for explaining gradle files.. And whenever I create a new project, it shows an error " Error:Execution failed for task ':app:preDebugAndroidTestBuild'. > Conflict with dependency 'com.android.support:support-annotations' in project ':app'. Resolved versions for app (26.1.0) and test app (27.1.1) differ. See d.android.com/r/tools/test-apk-dependency-conflicts.html for details. " I solve this error by rebuilding the project again and again whenever I use Android Studio.. How to permanently solve this error.. Plzz help me...

[@stiphenrobert4469]

After logout i getback to mainactivity.. But when i click log in again without filling email and password... It automatecally filled with prevoius email and password.. If this heppens then what about the security issue.. Plz plz plz help me

[@yahya-imammunir7381]

hi, you can clear the field at the end of every successful login

[@atharvapatkar9674]

alt+0 not working in my android studio pls help

[@ProfessorDK]

Check your num lock

[@ashutoshmishra1787]

Click alt+insert

[@vibhanshutyagi701]

Hello, Professor DK. I am making a login page where in i have a login screen without any registration part, so basically i just need to directly login using a username and password using a web service and furthermore once i login and exit the app and go offline then when i login, i must be login in offline mode using shared preference. Could you help me in solving this problem and would love to work on a project to side by side. Waiting to hear a positive reply from you And please tell if you would like to know more so i could provide you with a source of contact through a mail

[@ProfessorDK]

You could proceed with the same login functionality as firebase without registration part. The only difference is when you store the password on firebase it is encrypted. So when you intend to put the password into shared preferences, make sure you some encryption algorithms which make the password secure. This is because shared preference generates a local file on your phone, which anyone can access. And as much as I want to help side by side, I'm busy with projects of my own. But glad to help if u face any problems :)

[@vibhanshutyagi701]

Professor DK thanks a lot for the help. Will keep in touch for any further help if needed

[@shanusharma3722]

Plz make a one video logout with navigation drawer because I am so much confusion to apply this code on navigation drawer sign out fragment activity Plz make a one video I am waiting for your video

[@fzfxfcf]

anyone knows a way without having to use the "firebase-auth"??

[@vtvirtual6877]

FirebaseAuth firebaseauth getting error what to do?

[@ProfessorDK]

Have you added the dependency lines in gradle build?

[@fzfxfcf]

@@ProfessorDK I have! this: implementation 'com.google.firebase:firebase-auth:19.3.0' Do you know of a different way without using it?

[@len5120]

Sir my application got crash when i put navigation drawer after watching your navigation drawer tutorial. please help

[@ProfessorDK]

+lenin singh Could you tell me the error seen in your logcat?

[@abhijeetdhivar3415]

Wherever I enter username and password and click on login after successful registration then Login Failed message print how can solve it

[@ProfessorDK]

Are your credentials getting registered on the database?

[@abhijeetdhivar3415]

Professor DK Thank you so much

[@abhijeetdhivar3415]

Can we create menu in android version 2.1.3?

[@ProfessorDK]

Yes u can :)

[@abhijeetdhivar3415]

Professor DK OK thanks

[@izfimanshaf]

why cant i press alt + 0?

[@fionalishal5638]

try alt+insert i got it by doing this

[@ProfessorDK]

Turn off numlock and then try. You can always right click in the editor to get those options too :)

[@shubhamjamdhade7351]

sir plz uplode video for to create logout button in nevigation plnel

[@ProfessorDK]

+shubham jamdhade Yes, will be added soon :)

[@patelvaibhavee1766]

Sir error parsing xml : unbound prefix

[@ProfessorDK]

Check your XML layout. I guess theres some error in that :)

[@ezhilp5978]

Multiple root tag error