subclassing

问题 There's a class (not created by me, from a 3rd party library) that has no __init__ declared (other than object 's __init__ ), and this is its __new__ : def __new__(cls, uid): self = super().__new__(cls, uid) self._info = get_info_from_uid(uid) return self I can't see why didn't they just use __init__ here, but they didn't. Now I'd like to subclass this and give it an additional attribute; before I checked the source-code of the class (only the documentation), I thought it's just using __init_

问题 The Parse documentation for adding properties and methods on PFObject subclasses conveniently skips the Swift syntax in their sample code listing just the Objective-C syntax: https://parse.com/docs/ios_guide#subclasses-properties/iOS // Armor.h @interface Armor : PFObject<PFSubclassing> + (NSString *)parseClassName; @property (retain) NSString *displayName; @end // Armor.m @dynamic displayName; Has anyone figured out a work around for Swift's lack of dynamic synthesizers in order to implement

问题 For convenience, I wanted to subclass socket to create an ICMP socket: class ICMPSocket(socket.socket): def __init__(self): socket.socket.__init__( self, socket.AF_INET, socket.SOCK_RAW, socket.getprotobyname("icmp")) def sendto(self, data, host): socket.socket.sendto(self, data, (host, 1)) However, I can't override socket.sendto : >>> s = icmp.ICMPSocket() >>> s.sendto <built-in method sendto of _socket.socket object at 0x100587f00> This is because sendto is a "built-in method". According to

问题 For convenience, I wanted to subclass socket to create an ICMP socket: class ICMPSocket(socket.socket): def __init__(self): socket.socket.__init__( self, socket.AF_INET, socket.SOCK_RAW, socket.getprotobyname("icmp")) def sendto(self, data, host): socket.socket.sendto(self, data, (host, 1)) However, I can't override socket.sendto : >>> s = icmp.ICMPSocket() >>> s.sendto <built-in method sendto of _socket.socket object at 0x100587f00> This is because sendto is a "built-in method". According to

问题 I want to create a text display area (either UILabel or UITextView) in my iPhone app which (1) allows scrolling and (2) does not allow selection. I have tried the following techniques unsuccessfully: Basic UILabel: Didn't allow scrolling, and clipped text to the bottom of UILabel space on screen. Giant UILabel within a UIScrollView: the UILabel kept placing the text (vertically) at the center of the giant UILabel, so it often was outside of my UIScrollView. UITextView: So far this approach

问题 I'm trying to detect some events that VSTO doesn't provide such as WM_MOVE, WM_SIZE, etc in order to adjust the position of a window. This window is created by the add-in I'm working on and should react when the Word window is changed. I've basically manage to do my task but a very annoying problem remains. Whenever I close Word it pops up its crash handler. Obviously, this has something to do with the improper disposal of the NativeWindow-based object that I use. I've placed a button in the

问题 I'm overwriting UINavigationController to replace the default navigationBar property with an instance of my own subclass of UINavigationBar . So I tried something like _navigationBar = [[SBNavigationBar alloc] init]; in my -initWithRootViewController: . But that didn't work out as I expected it. There's still the default navigationBar being displayed. So what's the best point to overwrite the navigationBar ? Thanks in advance –f 回答1: If you check the documentation http://developer.apple.com

问题 protected: virtual void paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const { QHeaderView::paintSection(painter, rect, logicalIndex); painter->drawRect(2, 2, 10, 10); } Rectangle is not painting. But when paintSection removed it is painting. I need to draw rectangle after call base paintSection. 回答1: As it was answered in this your question, rect is an area your should paint at. If you paint outside of this area your drawings might be erased by painting of other cells.

问题 I know that this is a newbie question but I am a newbie so here goes: I wish to use Chalkduster font quite a lot throughout my app (buttons, labels etc) and have tried subclassing UILabel to achieve this. I have the following in Default.h: #import <UIKit/UIKit.h> @interface Default : UILabel { UILabel *theLabel; } @property (nonatomic, strong) IBOutlet UILabel *theLabel; @end and this in my .m: #import "Default.h" @implementation Default - (id)initWithFrame:(CGRect)frame { self = [super

问题 I have a basic class named APIGroup that exists for the sole purpose of subclassing (it is not [yet] used for anything but certain static properties that are accessed by the subclasses). It looks somewhat like this: public class APIGroup { public static let someProperty : String = "I am a property!" } And I have a subclass, Track , which defines a type method search as follows: public class Track : APIGroup { public static func search(name: String) -> Void { print("Track search initiated.