overriding

问题 Given the following code (without virtual inheritance) : class A { public: virtual void f() = 0; }; class B : public A { public: virtual void f() {} }; class C : public A { public: virtual void f() {} }; class D : public B, public C { /* some code */ }; int main() { D d; return 0; } the code compile. On the other hand , here : class A { public: virtual void f() = 0; }; class B : virtual public A { virtual void f() {} }; class C : virtual public A { virtual void f() {} }; class D : public B,

问题 I had thought that Generics in C# were implemented such that a new class/method/what-have-you was generated, either at run-time or compile-time, when a new generic type was used, similar to C++ templates (which I've never actually looked into and I very well could be wrong, about which I'd gladly accept correction). But in my coding I came up with an exact counterexample: static class Program { static void Main() { Test testVar = new Test(); GenericTest<Test> genericTest = new GenericTest

问题 How to underline a UILabel in Swift? I searched the Objective-C ones but couldn't quite get them to work in Swift. 回答1: You can do this using NSAttributedString Example: let underlineAttribute = [NSUnderlineStyleAttributeName: NSUnderlineStyle.StyleSingle.rawValue] let underlineAttributedString = NSAttributedString(string: "StringWithUnderLine", attributes: underlineAttribute) myLabel.attributedText = underlineAttributedString EDIT To have the same attributes for all texts of one UILabel, I

问题 I am getting a compile time error with Java: MyClass is not abstract and does not override abstract method onClassicControllerRemovedEvent( wiiusej.wiiusejevents.wiiuseapievents.ClassicControllerRemovedEvent) in wiiusejevents.utils.WiimoteListener) Here is the class: import wiiusej.WiiUseApiManager; import wiiusej.Wiimote; import wiiusej.wiiusejevents.physicalevents.ExpansionEvent; import wiiusej.wiiusejevents.physicalevents.IREvent; import wiiusej.wiiusejevents.physicalevents

问题 So, I've got a custom class that has a __mul__ function which works with ints. However, in my program (in libraries), it's getting called the other way around, i.e., 2 * x where x is of my class. Is there a way I can have it use my __mul__ function for this? 回答1: Just add the following to the class definition and you should be good to go: __rmul__ = __mul__ 回答2: Implement __rmul__ as well. class Foo(object): def __mul__(self, other): print '__mul__' return other def __rmul__(self, other):

问题 Is there any way to override a non-virtual method? or something that gives similar results (other than creating a new method to call the desired method)? I would like to override a method from Microsoft.Xna.Framework.Graphics.GraphicsDevice with unit testing in mind. 回答1: No, you cannot override a non-virtual method. The closest thing you can do is hide the method by creating a new method with the same name but this is not advisable as it breaks good design principles. But even hiding a

问题 Is there any way to override a non-virtual method? or something that gives similar results (other than creating a new method to call the desired method)? I would like to override a method from Microsoft.Xna.Framework.Graphics.GraphicsDevice with unit testing in mind. 回答1: No, you cannot override a non-virtual method. The closest thing you can do is hide the method by creating a new method with the same name but this is not advisable as it breaks good design principles. But even hiding a

问题 Is there any way to override a non-virtual method? or something that gives similar results (other than creating a new method to call the desired method)? I would like to override a method from Microsoft.Xna.Framework.Graphics.GraphicsDevice with unit testing in mind. 回答1: No, you cannot override a non-virtual method. The closest thing you can do is hide the method by creating a new method with the same name but this is not advisable as it breaks good design principles. But even hiding a

问题 Well, I am doing something in which I want to disable all hard buttons of the device. Hard buttons like Power, Home, Volume up, Volume down, Search, Back. I have successfully overridden almost all buttons here except Power. So I just want you people to see and please share some ideas so that I get can away with it. I am getting the long press Power keyevent in onDispatchKeyEvent() , in the same way I want to catch the short click of the same. Moreover when pressing power I also tried to stop

问题 I have a function, a() , that I want to override, but also have the original a() be performed in an order depending on the context. For example, sometimes when I'm generating a page I'll want to override like this: function a() { new_code(); original_a(); } and sometimes like this: function a() { original_a(); other_new_code(); } How do I get that original_a() from within the over-riding a() ? Is it even possible? Please don't suggest alternatives to over-riding in this way, I know of many. I