interface

问题 Can I can create public static final variables in an interface? Can I keep some common constant values defined in these files? 回答1: Yes, you can: public interface Constants { public static final int ZERO = 0; } However, it's generally reckoned not to be a good idea these days. It's not so bad if the interface has a real purpose as well , and the constants are likely to be used by most of the implementations... but introducing an interface just to make it easier to get to constants is an abuse

问题 This is a philosophical question about C# fundamentals: I am wondering how close an interface may be simulated by fully abstract class. Assume we have following interface: public interface INativeInterface { void PerformAction(); String Property { get; set; } } And following abstract class: public abstract class ISimulatedInterface { public abstract void PerformAction(); public abstract String Property { get; set; } } They are having so much in common, aren't they? The differences I know are

问题 This question already has an answer here : typescript: make class objects iterable (1 answer) Closed 2 years ago . I have a project that includes many classes that ideally would implement the Iterable<T> and/or Iterator<T> interfaces. However I cannot seem to find a standard TypeScript definition of these interfaces (for example in typescript-collections or some similar package). I understand these are somewhat standardized in ECMAScript 6 through the Symbol.iterator mechanism, but my target

问题 Usually, treating a struct S as an interface I will trigger autoboxing of the struct, which can have impacts on performance if done often. However, if I write a generic method taking a type parameter T : I and call it with an S , then will the compiler omit the boxing, since it knows the type S and does not have to use the interface? This code shows my point: interface I{ void foo(); } struct S : I { public void foo() { /* do something */ } } class Y { void doFoo(I i){ i.foo(); } void

问题 As I read here http://msdn.microsoft.com/en-us/library/75e8y5dd%28v=VS.100%29.aspx It is possible to have get in an Interface BUT NOT set ? OR if I want getter and setter in Interface, do I have to use the old syntax getVar setVar just because new syntax doesn't fit Interface syntax? Update: If I must omit set in Interface, does this means I cannot enforce class to have setter which defeats the purpose of having an Interface in this case as I can only partially enforce? 回答1: No. I think you

问题 This interface provides one method, namely getContentTypeFor(String fileName). However, I have no idea how to use it. I implemented interface in Eclipse and ended with: import java.net.FileNameMap; public class Fnam implements FileNameMap { public static void main(String[] args) { } @Override public String getContentTypeFor(String fileName) { return null; } } The method returns null. How should I change it to get the MIME type ? 回答1: It is interface for inner implementation of JDK, and in

问题 In my interface I have following defined List<IFoo> GetListOfFoo<T>(Expression<Func<T, bool>> predicate) where T : IFoo; In my implementation I'll cast the expression in the specific type: if (typeof(T) == typeof(Foo)) { Expression converted = Expression.Convert(predicate.Body, typeof(Foo)); Expression<Func<Foo, bool>> newPredicate = Expression.Lambda<Func<Foo, bool>>(converted, predicate.Parameters); } I try to use my implementation like this: Expression<Func<Foo, bool>> predicate = c => c

问题 I have a class that implements properties in a specific way, to handle some custom requirements for our business logic system. This "specific way" makes the properties non-operational in the context of data binding. Basically, if I drop an object of our class onto a form, data binding finds nothing on the object, and the property inspector for that object, though it lists the properties, doesn't allow me to edit them. What I'm wondering is if there's an interface or similar that I can

问题 See Updates in the end : The current code-base has 1.4k line of purely procedural code which sends sms (has business logic, db connectivity, and everything in one gigantic if conditional nested with countless more if s, no functions, full of literals, a genuine DailyWTF? candidate). And I have decided to bite the bullet and rewrite the whole damn thing from scratch. The thing is, this will be my first OOP experience. I read as much as I can about OOD and good practices and decided to start

问题 In my Android application, I have a fragment activity which it has a progressbar. This progress bar set to visible when any fragment invoke the interface. Therefore, the code for fragment class is like this: public class MainScreen extends FragmentActivity { public interface OnConnectingToInternet { public void showProgressbar(boolean flag); } // rest of codes . . . // Implementing Interface public void showProgressbar(boolean flag) { if(flag){ myProgressbar.showProgressBar(); } else {