constructor

问题 I have two constructors in two different js files. I want the constructors to have two methods that are the same (same name and functionality) and one method that is called the same but works differently (same name but not the same functionality). There will also be a couple of other properties that are the same in both constructors. The way I have tried to achieve this is by having one of the constructors inherit the other and then declare a new method with the same name as an old one (see

问题 I have abstract class A abstract class A{ def this(obj:Object){ this() obj match{ case s:String => stringMethod(s) case n:Int => intMethod(n) } def stringMethod(s:String) def intMethod(n:Int) } and I have a class that extends this class class B(obj:Object) extends A(obj){ var s:String = null def stringMethod(s:String){ this.s = s } def intMethod(n:Int){ this.s = n.toString } } The point of this class is to instantiate an object and its variables depending on the class type of the object used

问题 I have abstract class A abstract class A{ def this(obj:Object){ this() obj match{ case s:String => stringMethod(s) case n:Int => intMethod(n) } def stringMethod(s:String) def intMethod(n:Int) } and I have a class that extends this class class B(obj:Object) extends A(obj){ var s:String = null def stringMethod(s:String){ this.s = s } def intMethod(n:Int){ this.s = n.toString } } The point of this class is to instantiate an object and its variables depending on the class type of the object used

问题 class Person(name: String = "noname", age:Int = -1){} object ReflectionTester{ def main(args: Array[String]) { val m = ru.runtimeMirror(getClass.getClassLoader) val classTest = m.staticClass("Person") val theType = classTest.toType //class mirror val cm = m.reflectClass(classTest) val ctor = theType.decl(ru.termNames.CONSTRUCTOR).asMethod } } Invoking class mirror gives me the default constructor of passing name and age but there are inferred constructor too right where i can create a person

问题 I'm following this auth0 tutorial, and it says there: The authentication service's handleAuth() method must be called in the app.component.ts constructor so it will run on initialization of our app: // src/app/app.component.ts import { AuthService } from './auth/auth.service'; ... constructor(private auth: AuthService) { // Check for authentication and handle if hash present auth.handleAuth(); } ... However, documentations and answers like this one say: Mostly we use ngOnInit for all the

问题 In Android, if a TextToSpeech instance fails to initialize (the callback invoked indicating the completion of the TextToSpeech engine initialization returns TextToSpeech.ERROR), does that mean that subsequent attempted method calls to that instance will result in null pointer exceptions? Example... We initialize the object: t1 = new TextToSpeech(getApplicationContext(), new TextToSpeech.OnInitListener() { @Override public void onInit(int status) { if (status == TextToSpeech.ERROR) { Log.i(

问题 For a project I am looking at a case where the following situation exists. There is a class foo which requires an identifying number x when constructed. So its constructor argument looks something like foo(x). Now I want to derive a class based on foo, called bar, which will basically hold two foo's internally and to the outside world acts as a single foo. The way I want to do this is by use of two constructor arguments y and z for bar, which will then, in the constructor, generate foo(y) and

问题 I want to create an array of polymorphic objects which have constructors taking different dummy arguments depending on their dynamic type. Having read about user-defined and structure constructors, I see no way to apply these concepts to dynamically allocated objects. Having a background in C++, I was used to the notion that I could use one and the same constructor "member function" when allocating objects either dynamically or on the stack, but how can I explicitly call user-defined Fortran

问题 This is a very basic question about subclasses in java, I still don't get it... Suppose I have a superclass with three fields and with only the default constructor: public class Superclass { public int a; public int b; public int c; } and I want to add a field x. I cannot change Superclass , so I make a subclass: public class Subclass extends Superclass { public int x; public Subclass(Superclass s) { super(); // what to do?? } } I now want to generate a Subclass object from an existing

问题 I'm trying to call a modal function in the constructor in Angular 4 but the function get highlighted that is not properly called and when the page is loaded not error is read in the log and the modal is not popping up as its suppose to. The screen gets dark alright but the text in the modal doesn't show up. constructor(public formBuilder: FormBuilder, public router: Router, public toastr: ToastrService, public http: HttpClient, public modalService: BsModalService,) { if (this.getWardData) {