Unable to get user email, as a result of this i am getting NullPointer

Question

My profileActivity wont start due to getting a NullPointer exception, I assume the problem is with

FirebaseUser user = firebaseAuth.getCurrentUser();
textViewUserEmail.setText("Welcome " + user.getEmail());`

and that email is Null but I cant understand why. Here is my code:

import com.google.firebase.auth.FirebaseAuth;

inside onCreate:

textViewUserEmail = (TextView) findViewById(R.id.textViewUserEmail);

firebaseAuth = FirebaseAuth.getInstance();

if (firebaseAuth.getCurrentUser() == null) {
    finish();
    startActivity(new Intent(this, Home.class));
}

FirebaseUser user = firebaseAuth.getCurrentUser();
textViewUserEmail.setText("Welcome " + user.getEmail());

Here is the log error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.liamthedeveloper.foodiez/com.liamthedeveloper.foodiez.ProfileActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getEmail()' on a null object reference
                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2927)
                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2988)
                                                   at android.app.ActivityThread.-wrap14(ActivityThread.java)
                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1631)
                                                   at android.os.Handler.dispatchMessage(Handler.java:102)
                                                   at android.os.Looper.loop(Looper.java:154)
                                                   at android.app.ActivityThread.main(ActivityThread.java:6682)
                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)
                                                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getEmail()' on a null object reference
                                                   at com.liamthedeveloper.foodiez.ProfileActivity.onCreate(ProfileActivity.java:66)
                                                   at android.app.Activity.performCreate(Activity.java:6942)
                                                   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1126)
                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2880)
                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2988) 
                                                   at android.app.ActivityThread.-wrap14(ActivityThread.java) 
                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1631) 
                                                   at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                   at android.os.Looper.loop(Looper.java:154) 
                                                   at android.app.ActivityThread.main(ActivityThread.java:6682) 
                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520) 
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)

`Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getEmail()' on a null object reference` -> This is the problem. It seems `user` is `null`. — S.L. Barth is on codidact.com, Sep 07 '17 at 11:25
@Sahil my 66th line is textViewUserEmail.setText("Welcome " + user.getEmail()); — liam, Sep 07 '17 at 11:27
We have a standard Q&A on this subject: [What is a NullPointerException](https://stackoverflow.com/q/218384/812149). You may be interested in reading it. — S.L. Barth is on codidact.com, Sep 07 '17 at 11:27
i think you have not logged in with google that is why it is null. user is null — Sahil, Sep 07 '17 at 11:29

score 0 · Answer 1 · answered Sep 07 '17 at 11:28

0

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getEmail()' on a null object reference

It is clearly that the object of FirebaseUser is null,it means that the user in your code is null, not the email is null.

answered Sep 07 '17 at 11:28

杜咸鱼

19
5

how is this the case if it is set to 'FirebaseUser user = firebaseAuth.getCurrentUser();' – liam Sep 07 '17 at 11:31
maybe firebaseAuth.getCurrentUser() return a null, how can u confim user != null? – 杜咸鱼 Sep 07 '17 at 11:35

score 0 · Accepted Answer · answered Sep 07 '17 at 11:29

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
String uid = user.getUid();

String name = user.getDisplayName();

Then add this check to avoid NullPointerException

if(!TextUtils.isEmpty(name))
    textViewUserEmail.setText("Welcome " + user.getEmail());

rckrd · Answer 3 · 2017-09-07T11:38:17.663

You should rethink your null check of the Firebase user object.

if (firebaseAuth.getCurrentUser() == null) {
    finish();
    startActivity(new Intent(this, Home.class));
}

This will not stop the execution of onCreate, hence you will invoke a method on a null reference.

Make sure to stop the execution in your null check, i.e :

if (firebaseAuth.getCurrentUser() == null) {
    finish();
    startActivity(new Intent(this, Home.class));
    return;
}

This may be even more clear.

if(objectToCheck != null){
 // objectToCheck can be used
}else{
 // Handle the case when objectToCheck is null 
}

Unable to get user email, as a result of this i am getting NullPointer

3 Answers3