interface

问题 I have been looking at stackoverflow to solve my problem and found something pretty good, but it does not work for me or I am to stupid to see it (How to implement OnFragmentInteractionListener) I want to place a fragment inside a Frame, so I created it and so on. I have to implenet an interface and its method. I (think) I did it, but my App crashes everytime... *Edit: My App crashes, when I call openHome or openRecommended, the onCreate method works, I get these errors, but everything is

问题 How can we use the methods of a private interface in our code? Abstract classes are something which cannot be instantiated. So, if we need to use methods of abstract class, we can inherit them and use their methods. But, when we talk about interfaces, we need to implement them to use their methods. 回答1: The private keyword means "anyone in the same class": public class Foo { private interface X {...} private class X1 implements X {...} } This means all classes declared inside of Foo can use

问题 The issue appears is when I have a class implementing an interface, and extending a class which implements an interface: class Some : SomeBase, ISome {} class SomeBase : ISomeBase {} interface ISome{} interface ISomeBase{} Since typeof(Some).GetInterfaces() returns and array with ISome and ISomeBase, i'm not able to distinguish if ISome is implemented or inherited (as ISomeBase). As MSDN I can't assume the order of the interfaces in the array, hence I'm lost. The method typeof(Some)

问题 Well I've been watching some tutorials about Spring dependency injection as well as MVC, but I still seem to not understand how we can instantiate classes specifically? I mean if for instance I have a variable @Autowired ClassA someObject; How can I make spring create someObject as an Instance of ClassB which would extend ClassA? like someObject = new ClassB(); I don't really understand how it works in spring, does the ContextLoaderListener do it automatically or do we have to create some

问题 I have 2 interfaces IA and IB. public interface IA { IB InterfaceB { get; set; } } public interface IB { IA InterfaceA { get; set; } void SetIA(IA value); } Each interfaces references the other. I am trying to serialize ClassA as defined below. [Serializable] public class ClassA : IA { public IB InterfaceB { get; set; } public ClassA() { // Call outside function to get Interface B IB interfaceB = Program.GetInsanceForIB(); // Set IB to have A interfaceB.SetIA(this); } } [Serializable] public

问题 I have a case where a complex partial view needs different validation of fields depending on where the partial view is used. I thought I could get around this by making the partial view take an interface as the model type and implementing two different ViewModels based on the interface. The data annotations in the two ViewModels would be different. I would then supply an instance of the correct ViewModel to the partial view. But what I'm finding is that the only annotations that are

问题 I define an enum class that implements Neo4j's RelationshipType : enum class MyRelationshipType : RelationshipType { // ... } I get the following error: Inherited platform declarations clash: The following declarations have the same JVM signature (name()Ljava/lang/String;): fun <get-name>(): String fun name(): String I understand that both the name() method from the Enum class and the name() method from the RelationshipType interface have the same signature. This is not a problem in Java

问题 Salut to all Java gurus! Since Java8 we can have default implementations in interfaces (yay!). However problem arises when you want to log from default method. I have a feeling that it is not wise to call .getLogger() every time I want to log something in a default method. Yes, one can define static variable in an interface - but that is not a good practice for interfaces anyway + it exposes the logger (must be public). Solution I have at the moment: interface WithTimeout<Action> { default

问题 I have an interface with several method definitions, and I would not like to require some of them. Is this possible? if so, how can i implement this? I have tried setting an annotation of @Optional but this doesn't seem to work. Do i have to define the Optional annotation somewhere? 回答1: Although I agree with the other answers, one should note that such optional methods exist in the JDK. For example, List.add() is optional. Implementations must throw an UnsupportedOperationException if they

问题 I'm building a decent sized application in ASP.NET/VB.NET with various objects... I've never used interfaces before, and a fellow programmer balked when I mentioned this to him. Can anyone give me a quick overview on how they're used, what they're used for, and why I would use them? Maybe I don't need to use them for this project, but if they would help, I surely would love to try. Thanks so much! 回答1: Once you "get" interfaces, OOP really falls into place. To put it simply, an interface