LapitChat | sample demonstrates how to automatically generate thumbnails

I have this code in my activity

I want to save in the firebase storage, a photo that's cropped using the CropImage libraray from github. Everything works all right, until I hit the crop button. This is how I get and store the image from the Crop Image Activity;

I have one chat app. One is published on play store and another is my Android Studio project for this app, which is updated after the published. Now how can I test the updated without publish again on play store? Should I first uninstall the play store app from my phone and after run the project from my Android Studio? Here is my app link:https://play.google.com/store/apps/details?id=com.jimmytrivedi.lapitchat

In my chat app, I'm adding Phone verification from user. So I want that when user will enter the number, after that sendVerification button should be setEnabled(true) and I set setEnabled(false) as default, but when I run the app, it is still showing as enabled without entering the digits.

activity_phone_auth.xml

I don't know why I confuse with simple if/ else condition? In my app, phone verification part, Bydefault I set sendVerification button disable, and when I enter text then it should enable. but it is not enabling? What is wrong with my condition? even if I try with else part, same problem!

XML

In my chat app like WhatsApp, I also added the friend req functionality, where users can be friend and unfriend with firebase database. Now the bug in my app is: I should not able to send friend request to myself, it must should Invisible the button but I don't know where should I hide. I'm bit confuse.

Control flow of my app: Fresh app install - login/signup(StartActivity) - redirect to MainActivty - here I set menu layout and onOptionsItemSelected(MenuItem item) - so there is All users option - from there I select any particular user(UsersActivity) - so it open user profile of that user(which is ProfileActivity) - there I'll get send friend req option.

But In all users activity, like other users, I'm also showing in list, and when I click it on my profile it shows same thing like other users and also shwoing "send friend request" option. How can hide that?

I'm attaching UsersActivity (where all users incukding me are showing) and ProfileActivity (where particular user profile will open and there I can get the send friend req option)

UsersActivity.java

I've almost built one chat app with the login functionality using Firebase. But when I clear/delete all users from Firebase, uninstall app from my device and run the app from fresh and when it install and open app, it directly login it means it redirect to MainActivty instead of StartActivity where user can login or signup. I also faced this problem before and somehow I solved it, but again I improve the project, made some other classes and now again I'm facing the same problem.

Note:

1. When this things happens (automatically login), in my firebase database, it creates one ID automatically in under "Users" section. Actually it should happen only when user Singup.

2. I implemented the Facebook login button just before an hour, but this is not the issue, I'm sure about that, so please ignore Facebook login related stuff, this issue is getting before I implemented Facebook login button.

3. I tell you my app structure flow: When user first time install the app, it must redirect to StartActivity. If user already installed the app and login already, but not logout and simply closes the app and again open, it can login directly, it means it will redirect to MainActivity, no need to enter thr crendetials again.

4. Basically, my launcher activity is MainActivity, so if new user installed the app, it redirects from MainActivity to StartActivity (which is for login/singup).

5. LapitChat is a application class.

   I'm attaching MainActivity.java, StartActivity.java, LapitChat.java, and AndroidManifest.xml

MainActivity.java

I'm trying to replace the current fragment with a new fragment in a view pager with a click of a button.

I've tried various methods that leave me with errors such as:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.view.ViewPager.setAdapter(android.support.v4.view.PagerAdapter)' on a null object reference at in.tvac.akshaye.lapitchat.PersonalDetailsFragment$1.onClick(PersonalDetailsFragment.java:92)

Anyone with a solution to error being refferred above that will allow me to invoke fragments with the click of a button?

This is the current fragment code