I am trying to subclass a MKMapView in order to capture the UIResponder events for additional processing. I find that the subclass's overriding methods are not being triggered though. Is there something basic that I am missing with this implementation? initWithFrame is called in the subclass just fine. In the header: @class MyMapVie...
This is what I have: All objects that can be persisted on the database extend the DatabaseObject abstract class, which has all the logic code to actually watch for attribute changes and run the databas queries. I'm using two static variables to define object-specific details. I define them generically in the base class, and then suppose...
I have looked around and could not find any similar question. Here is the paragraph I got from Wikipedia: Polymorphism is not the same as method overloading or method overriding. Polymorphism is only concerned with the application of specific implementations to an interface or a more generic base class. Method overloading refers to me...
Hi, This is an example, I'm just curious as to how it would be achieved. I want to enable only subclasses of Animal to be able to set the number of legs that they have, but I still want them to be able to set their own colour. Therefore, I want to restrict classes further down the hierarchy from then altering this Legs property. publi...
What exactly does dispatchDraw(Canvas) method do? This is what the documentation says: protected void dispatchDraw (Canvas canvas) Since: API Level 1 Called by draw to draw the child views. This may be overridden by derived classes to gain control just before its children are drawn (but after its own view has been drawn). Parameters c...
Let says I have classes A, B and C B extends A C extends B all have public void foo() method defined. Now from C's foo() method I want to invoke A's foo() method (NOT its parent B but it's super super parent A's method) I checked super.super.foo(); But it's invalid syntax. How can I achieve this? ...
If i have an accessor and default property in a base class as follows: class base{ protected int _foo = 5; public int foo {get{return _foo;}set{_foo = value;}} } Then I derive this class, is it possible to override the default value of _foo? class derived:base{ // foo still returns 5? protected new int _foo = 10; } ...
I am attempting to inherit an ASP.NET RegularExpressionValidator and add some functionality to it. I inherited the control and added my custom properties. However, I would also like the client-side functionality to call a different JavaScript function. In order to do that, I will need to supress what is happening in the AddAttributesToR...
Hello guys, I am experiencing some problems while working with ComboBox. The display member for my combobox is not being populated by the overridden ToString method of class MAP. Here is my code: Form1.cs: private void Form1_Load(object sender, EventArgs e) { ... ... MAPList MAP = new MAPList(); comboBox1...
I've been fighting with trying to override a method in a generic abstract class. public abstract class Grandparent<T extends Grandparent> public T set(final T other) //does stuff I don't want to do public abstract class Parent<T extends Parent<T>> extends Grandparent<T> public T set(final Parent<?> other) // does stuff I wan...
I have a main class that has a Sub procedure with no implementation. Any derived class should override and implement this procedure, so I used MustOverride in the base class. Now, any time this procedure is called, I need to set a specific Boolean variable to True at the beginning of the procedure and set it to False at the end. Is the...
I always thought... overriding means reimplementing a function (same signature) in a base class whereas overloading means implementing a function with same name but different signature ... and got confused because sometimes people just don't care about the difference. Concerning new/delete: Are they overloaded or overridden? An ide...
Item 16 of Effective Java 2nd edition, favor composition over inheritance says the following "If the superclass acquires a new method in a subsequent release and you have the bad luck to have given the subclass a method with the same signature and a different return type, your subclass will no longer compile. If you’ve given the subcla...
Something that I see people doing all the time is: class Man(object): def say_hi(self): print('Hello, World.') class ExcitingMan(Man): def say_hi(self): print('Wow!') super(ExcitingMan, self).say_hi() # Calling the parent version once done with custom stuff. Something that I never see peop...
http://yfrog.com/5iumlp Here we have a class diagram for a personal program I am working on. The question I am asking is whether I have modelled the subclasses of UserControl Correctly. Specifically the base class has a method public abstract JComponent toComponent(). During implementation the subclasses should override the method keepi...
Hi! Can you please help me here, why the compiler does not infer the lambda input parameter right? Example: void Test(Action<string> n) { } void Test(Action<int,string> n) { } Ok so when doing this: obj.Test(x=>{}); // compiler doesn't know x is a string If I do this: obj.Test((x,y)=>{}); // that works, compiler know x is a int ...
I have two classes: class A { public: int i; }; class B : public A { public: int i; }; Suppose that I created an object for class B B b; Is it possible to access A::i using b? ...
Polymorphism allows the programmer either to inherit, override or to overload an instance method of Parent Class. But, it won't allow to make an instance method of parent class as more restrictive in child class. i.e it wont allow to use same name of parent class instance method, to declare as private in the child class. Also JVM iden...
Ok, maybe this is a stupid question. But i'm just wondering if this can be done in java. abstract public class ParentClass<T> { abstract public T getTest(); } in the subclass public class SubClass extends ParentClass<MyObject> { public MyObject getTest() { // I can return the object with class MyObject return null; } ...
I have a class called AddressCard from an example in "Programming in Objective C", and I'm implementing a isEqual: method. The signature of this method in NSObject uses loose typing for the parameter: - (BOOL)isEqual:(id)anObject OTOH, the sample code in the book uses strict typing: - (BOOL) isEqual:(AddressCard *) aCard I'm not s...