Develop Reference

Android Crashlytics Null Pointer exception, on a non null var

Craslitycs send a crash event of null pointer exception
NullPointerException: Attempt to invoke interface method 'java.lang.Object[] java.util.Collection.toArray()' on a null object reference
that refers to mutablelist.addAll(it.list), where it.list is an object from an api response.
When I try to check if this can be null, (it.list != null), AndroidStudio suggest Condition 'it.list != null' is always 'true' so, why this crash? And how can i fix it?
Thanks

You can check your list is empty or not by using kotlin collections function.
Use below function
ArrayList.isNullOrEmpty()
Reference link:
Kotlin collection

How to check for null objects in databinding android using null coalescing operator

How do I check for user != null using null coalescing operator.
The android documentation shows if user.displayName is null then lastName will be used.
But what if user is null?
How to add null check for user object in the following code ?
android:text="#{user.displayName ?? user.lastName}"

How to remove the 'is null error' in Flutter BLOC pattern?

When I run my app and select a dog breed of my choice and like it, I get an error saying -
════════ Exception caught by gesture ═══════════════════════════════════════════
The following NoSuchMethodError was thrown while handling a gesture:
The method 'contains' was called on null.
Receiver: null
Tried calling: contains(Instance of 'BreedsModel')
The likedList list contains all the dog breeds that I have liked. How do I solve this problem?
Here is the link to my code -
My Code

This is because you're calling the contains function on a null variable.
try printing the variable on which you're calling contains function.
print(likedList);
//output will "null"
make sure you're handling the null values

How to fix Null check operator used on a null value in Flutter

I am trying to save data to firebase, I used if(_formKey.currentState!.validate()) to valid the Textfield, and I get an error "Null check operator used on a null value in Flutter", Can anyone help me, please?
You can check the code.

'byte[] com.squareup.wire.ProtoAdapter.encode(java.lang.Object)' on a null object reference

Please refer screenshot in this link, Couldn't find the proper root cause of the null pointer exception.