anonymous-class

问题 In Java, it's common to write the following (e.g. for event handling) in order to make use of the template method pattern: abstract class SomeAbstractClass { public abstract void SomeFunction (); } //... SomeAbstractClass obj = new SomeAbstractClass () { public void SomeFunction () { /* implementation */ } }; In C++, the following compiles: class SomeAbstractClass { virtual void SomeFunction () = 0; }; // ... SomeAbstractClass * obj = new ( class : public SomeAbstractClass { virtual void

问题 According to the MSDN documentation on the StringComparer.OrdinalIgnoreCase property: The OrdinalIgnoreCase property actually returns an instance of an anonymous class derived from the StringComparer class. Is this a feature I'm unfamiliar with—anonymous types with inheritance? Or by "anonymous class" did the author simply mean "internal class deriving from StringComparer , not visible to client code"? 回答1: If you look at the source code for StringComparer, you can see that OrginalIgnoreCase

问题 Is there any way to use anonymous classes in C++ as return types? I googled that this may work: struct Test {} * fun() { } But this piece of code doesn't compile, the error message is: new types may not be defined in a return type Actually the code doesn't make any sense, I just want to figure out whether an anonymous class can be used as return type in C++. Here is my code: #include <typeinfo> #include <iterator> #include <iostream> #include <fstream> #include <cstring> #include <cstdlib>

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . What's the best practise(design and performance wise) for anonymous classes and static inner classes? Personally I would like to think that static inner classes provide better encapsulation and should give better performance as they dont have access to finalized variables

问题 We all know that when we create an anonymous class like this: var Employee = new { ID = 5, Name= "Prashant" }; ...at run time it will be of type: <>f__AnonymousType0<int,string> Is there any way to specify a meaningful name to such classes? 回答1: public class Employee {} 回答2: It's an anonymous type, that defeats the purpose. Those objects are designed to be temporary. Hell, the properties are even read-only. Sorry, I'm being a smart-ass. The answer is no, there is no way to tell the compiler

问题 RadioGroup radioGroup = (RadioGroup) findViewById(R.id.orientation); radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId) { case R.id.horizontal: group.setOrientation(LinearLayout.HORIZONTAL); break; case R.id.vertical: group.setOrientation(LinearLayout.VERTICAL); break; } } }); What is radioGroup.setOnCheckedChangeListener eactly? Is it a method? What are it's arguments then? 回答1:

问题 How do I access instance variables from inside the anonymous class's method ? class Tester extends JFrame { private JButton button; private JLabel label; //..some more public Tester() { function(); // CALL FUNCTION } public void function() { Runnable r = new Runnable() { @Override public void run() { // How do I access button and label from here ? } }; new Thread(r).start(); } } 回答1: How do I access instance variables from inside the anonymous class's method ? You simply access them if need

问题 How do I access instance variables from inside the anonymous class's method ? class Tester extends JFrame { private JButton button; private JLabel label; //..some more public Tester() { function(); // CALL FUNCTION } public void function() { Runnable r = new Runnable() { @Override public void run() { // How do I access button and label from here ? } }; new Thread(r).start(); } } 回答1: How do I access instance variables from inside the anonymous class's method ? You simply access them if need

问题 Or simply put can I do some thing like class A { public: virtual void foo() = 0; }; class B { public: A *a; b(){ a = new A() { void foo() {printf("hello");} } }; 回答1: No, C++ doesn't have anonymous classes like Java's. You can define local classes, like this: class B { public: A *a; b(){ struct my_little_class : public A { void foo() {printf("hello");} }; a = new my_little_class(); } }; Or maybe just a nested class: class B { private: struct my_little_class : public A { void foo() {printf(

问题 I want to use a PriorityQueue to do a topological sort on a graph. For brevity, I'd like to use an anonymous inner class for the comparator. However, I need access to the graph g in order to determine the in degree of the nodes I'm looking at. Is this possible? /** * topological sort * @param g must be a dag */ public static Queue<String> topoSort(DirectedGraph<String, DefaultEdge> g) { Queue<String> result = new PriorityQueue<String>(g.vertexSet().size(), new Comparator<String>() {