Flutter: The null value
In Dart 2.0, the Dart team added null safety to the Dart language. When a variable is
null it is because it does not have any reference to any object, or we can say that it does not have any value.
When we create a variable by default, it cannot have null values. If we try to compile the following code, it will fail:
String myName = null;
If we want to create a variable with null support, we must add a question mark like this:
String? myName = null;
When should we use a variable with null support?
We should only create a variable with null support when we are 100% sure that it can be
null this will help our IDE to understand if we are trying to assign
null to a non-null variable, so we won't be able to compile the app until these errors are fixed.