Firebaseauth.getinstance() Always Return Null

I know I can see so many questions on this topic on stackoverflow and I have tried almost all of them and haven't worked yet so this is my only option to post a new question. My pr

Solution 1:

Finally found the answer, it was because of the

tools:node="replace"

in the manifest. Just remove it and it will work fine.

Solution 2:

fix this method:

@OverridepublicvoidonStart() {
    super.onStart();


    FirebaseUserfirebaseUser= mAuth.getCurrentUser();//here u must have //instance first then use the methodif(firebaseUser != null){
        Toast.makeText(this.getContext(), "Already Sign in ", 
 Toast.LENGTH_SHORT).show();
    } else {
        Toast.makeText(this.getContext(), "mAuth Still null ", 
 Toast.LENGTH_SHORT).show();
    }
}

code below will work correct for u

@OverridepublicvoidonStart() {
    super.onStart();
        FirebaseApp.initializeApp(this.getContext());
        mAuth = FirebaseAuth.getInstance();

    FirebaseUserfirebaseUser= getInstance(); //first try without this line
    firebaseUser = mAuth.getCurrentUser();

    if(firebaseUser != null){
        Toast.makeText(this.getContext(), "Already Sign in ", 
Toast.LENGTH_SHORT).show();
    } else {
        Toast.makeText(this.getContext(), "mAuth Still null ", 
Toast.LENGTH_SHORT).show();
    }
}