I use Firebase PhoneAuth in my app and the following function is called after the verification is successfully finished. While I was doing some trial, I deleted the entire document of a user, who is authenticated using the phone number, from the collection called "users". Then when I try to open the app, the app crashes and gets java.lang.NullPointerException error. However, it doesn't show the error message for Log.d("Tag", e.message!!) in the .addOnFailureListener. How can I catch this type of error? Isn't .addOnFailureListener supposed to consider this as an error?
fun getUserDetail(fragment: HomeFragment) {
mFireStore.collection(Constants.USERS)
.document(getCurrentUserID())
.get()
.addOnSuccessListener { document ->
val user = document.toObject(User::class.java)!!
fragment.successUserDetail(user)
}
.addOnFailureListener { e ->
Log.d("Tag", e.message!!)
fragment.hideProgressDialog()
}
}
CodePudding user response：
You are getting that NullPointerException most likely at the following line of code:
val user = document.toObject(User::class.java)!!
And it makes sense since you say you have deleted the user from the collection.
Isn't .addOnFailureListener supposed to consider this as an error?
No, that NPE is not a failure, it just indicates that you have called a method on a document that doesn't exist, in other words, which is null. However, a failure may occur when, for example, the Firebase servers reject your request due to improper security rules. I have also written an article regarding that called:
If you want to avoid that NPE, in a Kotlin style, you shouldn't use the !! operator but:
document?.let {
val user = it.toObject(User::class.java)
fragment.successUserDetail(user)
}