AS3 / Flex：接口扩展接口

Question

In AS3/Flex, is it possible for me that one interface extends another interface ?

I have created interface A. Now I want to create another Interface B which extends interface A.

I google a lot but couldnt find any convincing answer. Please help.

Answer 1

Of course you can extend an interface :

Multiple interfaces can be inherited by another interface through the extends clause or by a class through the implements clause. Instances of a class that implements an interface be long to the type represented by the interface. Interface definitions must only contain function definitions, which may include get and set methods.

Keep in mind: Sometimes it is faster to just try it out or simply look in the Flex SDK source code. ;-)

${FLEX_HOME}\\frameworks\\projects\\framework\\src\\mx\\core\\IUIComponent.as :

package mx.core
{ 
...
public interface IUIComponent extends IFlexDisplayObject
{
...

Answer 2

In my comment I said Interfaces aren't extended; they are implemented. That should have been that interfaces are implemented by classes using the implement keyword. When you want a single interface to 'extend' multiple interfaces, just use the extends keyword and separate them by commas.

Take this interface, IMyFirstInterface:

public interface IMyFirstInterface {
 // method definitions here
}

And then take, this other interface, IMySecondInterface:

public interface IMySecondInterface {
 // method definitions here
}

Both are "Stand alone" meaning they don't have any relation to another interface. But, a third interface can extend them both, like this:

public interface IMyThirdInterface extends IMyFirstInterface, IMySecondInterface{
 // method definitions here
}

Your class will implement the Interface, like this:

public class myClass implements IMyThirdInterface{
 // other class stuff
}

myClass is required to include all the methods defined in iMyThirdInterface, IMyFirstInterface, and iMySecondInterface because it implements IMyThirdInterface which extends IMyFirstInterface and IMySecondInterface.

Off the top of my head; I have no idea how "collisions" are handled. If IMyFirstInterface and IMySecondInterface implement the same method with different signatures I would expect a compiler error.

Answer 3

Interfaces can extend other interfaces. Classes can extend classes. See the correlation here? Its like lego.

Interfaces implement classes. Classes implement interfaces. It should make sense now.