parent

问题 Having two simple classes; one with only parent attribute, and one with both parent and children attributes. This means that the one with both parent and children inherits from the one with only parent . Here's the class with only parent attribute. Let's call it Child since it can only be a child, not a parent. I'll use a method set_parent() to make it more clear, but I would use a setter in my actual code. class Child(object): def __init__(self, parent=None): self.__parent = None self.set

问题 I'm wondering what is the difference between using self:: and parent:: when a static child class is extending static parent class e.g. class Parent { public static function foo() { echo 'foo'; } } class Child extends Parent { public static function func() { self::foo(); } public static function func2() { parent::foo(); } } Is there any difference between func() and func2() and if so then what is it ? Thank you Regards 回答1: Child has foo() Parent has foo() self::foo() YES YES Child foo() is

问题 I'm trying to keep traveling route in core data and here is my data model. I have entity Coordinate keeping latitude and longitude in double, then I created Locatable entity and make relation between these two entities. Coordinate <-> Locatable then I have POI entity inherited Locatable these POI representing my route. finally I have Destination entity inherited POI using as my destination point Coordinate <-> Locatable | V POI | V Destination My Route class have points as one-to-many

问题 I'm trying to keep traveling route in core data and here is my data model. I have entity Coordinate keeping latitude and longitude in double, then I created Locatable entity and make relation between these two entities. Coordinate <-> Locatable then I have POI entity inherited Locatable these POI representing my route. finally I have Destination entity inherited POI using as my destination point Coordinate <-> Locatable | V POI | V Destination My Route class have points as one-to-many

问题 Note The example code is an abridged version but can run with a basic function. Please focus on class MainWindow(tk.Frame) Questions What kind of object can play the role of the parent or master for tkinter class initialization? In my case, see the example code, why can not pass self as parent to ProjectInfo(...) or ConfirmItems(...) in class MainWindow(tk.Frame) ? It would pop up an empty window if using self instead of self.parent . Reference This question originates from my comments on

问题 Sorry if the answer to this is obvious - its not to me and I can't seem to find a straight forward answer by searching. I've created a Container View Controller which as default comes with a child. I want to add a second (and third) child in the storyboard but I can see how to link up a new View Controller with the Container View Controller. Can anyone advise? Many thanks 回答1: Yup, it's one of those bizarre things about iOS ... it's like the most normal, common thing you need to do -------

问题 I would like all my objects to have an ID and I wish to serialise it for some child class but not for some others for example: public class A { protected Long id; ..getter and setter } public class B extends A { @Override @JsonIgnore public Long getId() {..} @Override @JsonIgnore public void setId(Long id) {..} } public class C extends B { @Override @JsonInclude public Long getId() {..} @Override @JsonInclude public void setId(Long id) {..} } public class Test { Set<C> tests ... ..getter

问题 I have been working on android development for a while, but I am still confused about this question.. From android documentation said, the event will start from root view, and dispatched to the child view. Which means viewgroup should get touch event before view(which is its child), but from what I have debugged, this is not the case... I create a RadioGroup, then add three radiobutton into it, every time when I click radiobutton, its click event is triggered. Radiogroup's click event is not

问题 I'm developing a touchscreen app. I have a form with buttons with the content "new player" and then a keyboard with a textbox is shown for the user to enter his name. Now I need that when I close (or while inputting the name) the button from the parent window change the content to the name that the user typed. But I cant make a binding to the parent.. how can I do it?? 回答1: Are you implementing the Model-View-ViewModel pattern in your WPF application, or using databinding at all? You don't

问题 I have a dropdown menu and want to change background of parent's button when hovering submenus. Any ideas how to achieve this so it will work not only in all modern browsers but preferably in IE8/IE9 too? Simple example, I want to change background of link "This black" while hovering his children ("When hover me" & "and me"). Is it possible with pure CSS? http://jsfiddle.net/PExLW/ I was thinking about adding certain classes when hovering certain li but it sounds like an overkill, also,