methods

问题 I am a new-comer in Java and in process of learning. I need a an answer of following question supported with valid theory. Consider the following line- Iterator itr = al.iterator(); where al is some collection object of ArrayList (class) type. I want to know what is here the return type of al.iterator() It is not definitely of a primitive data type, then it could be an object , but since every object belong to a class then it is of which class . Documentation and books etc says it has return

问题 I want to set a read-only attribute inside a class method. I have already tried this: class Foo(object): def __init__(self, v): self._set('_v', v) def _set(self, attr, v): setattr(self, attr, v) setattr(Foo, attr[1:], property(lambda self: getattr(self, attr))) but it is horrible. Is there another way? What I need to do is setting the property: class Foo(object): def __init__(self, v): self._v = v @ property def v(self): return self._v >>> f = Foo(42) >>> f.v 42 >>> f.v = 41 AttributeError:

问题 Okay, I've read half a dozen threads on this subject, but none of the solutions appear to address exact needs. Question: How does a Pure C (.c) function call a method inside a Pure Objective-C (.m) class? Every example / answer is using C inside an Objective-C (.m) method. I have a Pure C library that I have to create a simulator for, so I need to keep my Kernel in pure C and call out to my higher level emulation methods in Objective-C. Any attempt I make to create a reference and call a

问题 I've got a const method in my class, which cannot be changed to non-const. In this method, I need to call a non-const method but the compiler doesn't let me do that. Is there any way around it? Here is a simplified sample of my code: int SomeClass::someMethod() const { QColor saveColor = color(); setColor(QColor(255,255,255)); // Calling non-const method // .... setColor(saveColor); // restore color return 1; } 回答1: One of the challenges of doing const -correctness is you can't do it halfway.

问题 Sorry if this question has been asked before. I am using the Butterknife 5.0 with the latest version of Android Studio(0.5.7). How can I remove the "Method is never used" warning for methods that use the 'OnClick' Annotation of ButterKnife.I noticed that Eclipse doesnt give this warning for the 'OnClick' methods. Thanks in advance 回答1: The correct way in Android Studio to suppress these warnings is to press Alt+Enter on the method giving the Method 'yourFunction()' is never used warning, and

问题 I hava slight doubt regarding the Output of the Program of Constructor Chaining I showed Below: class Cube { int length; int breadth; int height; public int getVolume() { return (length * breadth * height); } Cube() { this(10, 10); System.out.println("Finished with Default Constructor of Cube"); } Cube(int l, int b) { this(l, b, 10); System.out.println("Finished with Parameterized Constructor having 2 params of Cube"); } Cube(int l, int b, int h) { length = l; breadth = b; height = h; System

问题 How can i check if a method in a web service is working fine or not ? I cannot use ping. I still want to check any kind of method being invoked from the web service by the client. I know it is difficult to generalize but there should be some way. 回答1: I use this method and it works fine : public bool IsAddressAvailable(string address) { try { System.Net.WebClient client = new WebClient(); client.DownloadData(address); return true; } catch { return false; } } 回答2: The only way to know if a web

问题 I have several similar methods, say eg. CalculatePoint(...) and CalculateListOfPoints(...). Occasionally, they may not succeed, and need to indicate this to the caller. For CalculateListOfPoints, which returns a generic List, I could return an empty list and require the caller to check this; however Point is a value type and so I can't return null there. Ideally I would like the methods to 'look' similar; one solution could be to define them as public Point CalculatePoint(... out Boolean

问题 Take this code: public class MyClass { private final Object _lock = new Object(); private final MyMutableClass _mutableObject = new MyMutableClass() public void myMethod() { synchronized(_lock) { // we are synchronizing on instance variable _lock // do something with mutableVar //(i.e. call a "set" method on _mutableObject) } } } now, imagine delegating the code inside myMethod() to some helper class where you pass the lock public class HelperClass { public helperMethod(Object lockVar,

问题 I keep getting an error saying that my functions are not defined when I was trying to call the prototype functions in the constructor and I dont know whats wrong with it. Here's the code I have: function Renderer() { initialiseWebGL(); initialiseShader(); initialiseBuffer(); } Renderer.prototype.initialiseWebGL() { //Do stuff. }; Renderer.prototype.initialiseShader() { //Do Shader's stuff }; Renderer.prototype.initialiseBuffer() { //Do Buffers }; What is wrong with it? 回答1: Your syntax is