Dart INTERFACE ( implements keyword ) Example. Dart Programming for Flutter #9.7
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Dart beginners tutorial. Learn how to implement an Interface in Dart language. Since dart has no direct keyword of 'interface' so we need to follow some rules to make a normal class to act like an Interface. Also, learn how to override method while implementing an Interface.
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Note: With the interface, we can implement multiple classes. Thus, implementing multiple inheritance would be possible with this interface concept.
If we use Remote as parent class and Override its two methods in child class Television, then television has its own implementation of these two methods ..... So why we need Interface here ?
I guess interface is used in very specific cases when you must override all the methods of the interface class. For the other cases, you can just override the extended class methods.
why you arent uploading videos anymore. i know you still like and love our comments but why did you stop uploading videos?
i am confused about data type are all objects but int or string or other are abstract class
and when i write
int x = 2;
i create object with type int
but int is abstract and i can't write int x = int();
pleasaaaaaaaaaaase i am very confused help ???
i didn't get it ... why we needed an abstract class when it;s as the same as the regular class
and in the implementation what is the use of it when you are going to copy all the subjects to the child clas
Hi Assolil, I am just studying this now, and I think I've found the answer for this in the book Quick Start Guide to Dart Programming, by Sanjib Sinha, I'm paraphrasing here... I guess that the key advantage is that with the abstract class, it cannot be instantiated, so you have the benefits of having a partial class implementation, which leaves the unimplemented piece to a subclass? An abstract class is also where we can define an interface but leave its implementation up to other classes. But, any class in dart abstract or concrete can be an interface.
What if Remote and SomeOtherClass have the same method, and override in the Television class then in actuality which class method will override?
If I'm going to use Implements, my class that will be implemented should not have to be abstract? Since I need to override the methods, in abstract class I just need to declare them. What's the point of using implement in an non abstract class?
I did not understand what u want to say
Thanks for the reply. I will try to explain with an example. This example makes more sense or not to understand implements and abstract class? It's my first day trying to understand them, so bare with me.
main() {
var volumeRemote=Remote();
volumeRemote.volumeUp();
var volumeTv=Tv();
volumeTv.volumeUp();
}
abstract class Volume {
void volumeUp();
void volumeDown();
}
class Remote implements Volume {
void volumeUp() => print("---volume up from remote----");
void volumeDown() => print("---volume down from remote----");
}
class Tv implements Volume {
void volumeUp() => print("---volume up from Tv----");
void volumeDown() => print("---volume down from Tv----");
}
The whole point is, if you want to use a class as interface then use implements keyword. I am unable to get your confusion. You can see abstract class video and compare it with interface video.
If I want to use a class as interface, should not the parent class be an abstract class? And use Implement on that parent class? using a normal class as you did as an interface doesn't make sense to me. my example just changed your code to an interface that makes sense to me. I was trying to understand if I'm thinking right or wrong. I know I can make an interface from any class, but should I? It's not a better approach from an abstract class? btw, your videos are very very good. I tried to watch lot's of different videos to learn Dart, your's are the best so far.
@@JoaoCSpeixoto Let me explain what i understood :
Have you ever played with remote control car?
when you press forward , car goes forward and vice versa,
since every function of remote have specific action on car...
we need to override function of remote with implement to make car actionable. Since car will have same no. of function as remote.
Implement help to create relation between remote forward and cars forward..
and for abstract class.... i don't think it can establish relation between two objects with different class. Imagine you try to play with your friends car but use your remote car... will car work? of course not because even though it has same function as your remote (abstract class) their is no tuning of signals.....
that tuning/relation is created by implement.
let me know if you understood.... or you have better explanation.
what is the diff between interface and abstract.
Hmm, so it seems that interfaces in dart programming language can have implementations in them. Doesn't this defeat the purpose of interface? How is it different from abstract class now?
Exactly my doubt.
Interfaces are not the same as in other programming languages.
"Class declarations are themselves interfaces in Dart."
www.tutorialspoint.com/dart_programming/dart_programming_interfaces.htm
Mahn you are good;
So obvoius well done man
when do we need to use override method. can someone explain me
Just when you saw an error or issues to write @override
Why we didn't use @override?
That's just annotation
I can't help but say that if it isn't mandatory then it isn't an interface.
Guess the purpose of this Interfaces and Abstract classes is to comply with the 'O' in SOLID principles?
Super sir👍
thanks
👌
I dont know where im gonna use this lol
widgets in flutter , good luck
what the heck is an interface.....explain the meanings of different terms first....the content is good but a lot of information missing in between and the course is not complete.
You should do a version of this, but in English....
First of all, you should tell a person what is an interface and related terms to it. You directly start with the implementation which is not a good practice. If a person is unaware of the terms or if he/she didn't code before then you are not a good teacher for him/her. Sorry, but that's the truth. You have change your style of teaching. Some of your videos are really good but some are real shit.
Kindly check java videos to understand interface in detail. This dart and kotlin series are intentionally not in detail.