I tried to call the Transilation(context) from it's class but can't be read in this class but i can read it in another class normaly but about the meal it's not a stateless or stateull widget its just a class has a data and constractor
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I want to understand the difference between extends, implements and with. When do I use each keyword?
Extends:
Use extends to create a subclass, and super to refer to the superclass.
Extends is the typical OOP class inheritance. If class a extends class b all properties, variables, functions implemented in class b are also available in class a. Additionally you can override functions etc.
You use extend if you want to create a more specific version of a class. For example the class car could extend the class vehicle. In Dart a class can only extend one class.
Implements:
Every class implicitly defines an interface containing all the instance members of the class and of any interfaces it implements. If you want to create a class A that supports class B’s API without inheriting B’s implementation, class A should implement the B interface.
Implements can be used if you want to create your own implementation of another class or interface. When class a implements class b. All functions defined in class b must be implemented.
When you're implementing another class, you do not inherit code from the class. You only inherit the type. In Dart you can use the implements keyword with multiple classes or interfaces.
With (Mixins):
Mixins are a way of reusing a class’s code in multiple class hierarchies.
With is used to include Mixins. A mixin is a different type of structure, which can only be used with the keyword with.
They are used in Flutter to include common code snippets. A common used Mixin is the SingleTickerProviderStateMixin.
extend can only be used with a single class at the time, BUT... you can easily extend a class which extends another class which extends another class which...! ;)
In fact, most Flutter widgets are already built like that.
Is there any possibility to map an existing individual of a class to another class with Protege functions in Jess? The function make-instance creates new instance, while modify-instance allows instance slot updates. But, I would like to use an existing class instance to make it as an instance of another class?
I have a controller written in grails where i have used name of a domain class to retrieve data from db. Now I want to test it using grails default test.
But it is returning a error:
java.lang.IllegalStateException: Either class [cre_service.AppPreferences] is not a domain class or GORM has not been initialized correctly or has already been shutdown. Ensure GORM is loaded and configured correctly before calling any methods on a GORM entity.
Sounds like you need to Mock you domain class e.g.
import spock.lang.Specification
import grails.test.mixin.Mock
#Mock( [AppPreferences] )
class YourControllerClassSpec extends Specification {
...
How can I get a model instance inside a DataAnnotationsModelMetadataProvider derived class in MVC2? To be more precise, how can I get the model instance to which a property belongs, inside a GetMetadataForProperty derived method?
i've been poking around RIM's PlayBook SDK and noticed they extend Object on a lot of their classes.
are there benefits to extending Object on a custom class that would normally be unextended?
package qnx.notificationManager
{
public class Notification extends Object
{
...
If you do not specify that your class extends another class, the compiler automatically makes your class extend Object. So the answer is that you don't gain any benefit; they must have just been trying to be explicit, or maybe the code was generated through decompilation.