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• How can I abstract out the core functionality of several Rails applications?

  - by hornairs

  I'd like to develop a number of non-trivial Rails applications which all implement a core set of functionality but each have certain particular customizations, extensions, and aesthetic differences. How can I pull the core functionality (models, controllers, helpers, support classes, tests) common to all these systems out in such a way that updating the core will benefit every application based upon it? I've seen Rails Engines but they seem to be too detached, almost too abstracted to be built upon. I can seem them being useful for adding one component to an existing app, for example bolting on a blog engine to your existing e-commerce site. Since engines seem to be mostly self contained, it seems difficult and inconvenient to override their functionality and views while keeping DRY. I've also considered abstracting the code into a gem, but this seems a little odd. Do I make the gem depend on the Rails gems, and the define models & controllers inside it, and then subclass them in my various applications? Or do I define many modules inside the gem that I include in the different spots inside my various applications? How do I test the gem and then test the set of customizations and overridden functionality on top of it? I'm also concerned with how I'll develop the gem and the Rails apps in tandem, can I vendor a git repository of the gem into the app and push from that so I don't have to build a new gem every iteration? Also, are there private gem hosts/can I set my own gem source up? Also, any general suggestions for this kind of undertaking? Abstraction paradigms to adhere to? Required reading? Comments from the wise who have done this before? Thanks!

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• WCF REST Starter Kit not filling base class members on POST

  - by HJG

  I have a WCF REST Starter Kit service. The type handled by the service is a subclass of a base class. For POST requests, the base class members are not correctly populated. The class hierarchy looks like this: [DataContract] public class BaseTreeItem { [DataMember] public String Id { get; set; } [DataMember] public String Description { get; set; } } [DataContract] public class Discipline : BaseTreeItem { ... } The service definition looks like: [WebHelp(Comment = "Retrieve a Discipline")] [WebGet(UriTemplate = "discipline?id={id}")] [OperationContract] public Discipline getDiscipline(String id) { ... } [WebHelp(Comment = "Create/Update/Delete a Discipline")] [OperationContract] [WebInvoke(Method = "POST", UriTemplate = "discipline")] public WCF_Result DisciplineMaintenance(Discipline discipline) { ... } Problem: While the GET works fine (returns the base class Id and Description), the POST does not populate Id and Description even though the XML contains the fields. Sample XML: <?xml version="1.0" encoding="utf-8"?> <Discipline xmlns="http://schemas.datacontract.org/2004/07/xxx.yyy.zzz"> <DeleteFlag>7</DeleteFlag> <Description>2</Description> <Id>5</Id> <DisciplineName>1</DisciplineName> <DisciplineOwnerId>4</DisciplineOwnerId> <DisciplineOwnerLoginName>3</DisciplineOwnerLoginName> </Discipline> Thanks for any assistance.

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• python list/dict property best practice

  - by jterrace

  I have a class object that stores some properties that are lists of other objects. Each of the items in the list has an identifier that can be accessed with the id property. I'd like to be able to read and write from these lists but also be able to access a dictionary keyed by their identifier. Let me illustrate with an example: class Child(object): def __init__(self, id, name): self.id = id self.name = name class Teacher(object): def __init__(self, id, name): self.id = id self.name = name class Classroom(object): def __init__(self, children, teachers): self.children = children self.teachers = teachers classroom = Classroom([Child('389','pete')], [Teacher('829','bob')]) This is a silly example, but it illustrates what I'm trying to do. I'd like to be able to interact with the classroom object like this: #access like a list print classroom.children[0] #append like it's a list classroom.children.append(Child('2344','joe')) #delete from like it's a list classroom.children.pop(0) But I'd also like to be able to access it like it's a dictionary, and the dictionary should be automatically updated when I modify the list: #access like a dict print classroom.childrenById['389'] I realize I could just make it a dict, but I want to avoid code like this: classroom.childrendict[child.id] = child I also might have several of these properties, so I don't want to add functions like addChild, which feels very un-pythonic anyway. Is there a way to somehow subclass dict and/or list and provide all of these functions easily with my class's properties? I'd also like to avoid as much code as possible.

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• Fluent NHibernate: Example of a one-to-many relationship on an abstract class of a table-per-subclas

  - by BigTommy79

  Hi All, I've been trying for ages to find an example (because I can't get it to work myself) of the correct mapping for a one-to-many relationship on an abstract class of a table-per-subclass implementation, in fluent nHibernate. An example below: I'm looking to map the list of Fines on the Debt abstract base class to the Fine class. if anyone knows of any tutorial or example they've come across before please let me know. Thanks, Tim public abstract class Entity { public int Id { get; set; } } public abstract class Debt : Entity { public decimal Balance { get; set; } public IList<Fine> Fines { get; set; } public Debt() { Fines = new List<Fine>(); } } public class CarLoan : Debt { } public class CreditCard : Debt { } public class LoanApplication : Entity { public IList<Debt> ExistingDebts { get; set; } public LoanApplication() { ExistingDebts = new List<Debt>(); } } public class Fine { public Int64 Cash { get; set; } }

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• Problem with inheritance and List<>

  - by Jagd

  I have an abstract class called Grouping. I have a subclass called GroupingNNA. public class GroupingNNA : Grouping { // blah blah blah } I have a List that contains items of type GroupingNNA, but is actually declared to contain items of type Grouping. List<Grouping> lstGroupings = new List<Grouping>(); lstGroupings.Add( new GroupingNNA { fName = "Joe" }); lstGroupings.Add( new GroupingNNA { fName = "Jane" }); The Problem: The following LINQ query blows up on me because of the fact that lstGroupings is declared as List< Grouping and fName is a property of GroupingNNA, not Grouping. var results = from g in lstGroupings where r.fName == "Jane" select r; Oh, and this is a compiler error, not a runtime error. Thanks in advance for any help on this one! More Info: Here is the actual method that won't compile. The OfType() fixed the LINQ query, but the compiler doesn't like the fact that I'm trying to return the anonymous type as a List< Grouping. private List<Grouping> ApplyFilterSens(List<Grouping> lstGroupings, string fSens) { // This works now! Thanks @Lasse var filtered = from r in lstGroupings.OfType<GroupingNNA>() where r.QASensitivity == fSens select r; if (filtered != null) { **// Compiler doesn't like this now** return filtered.ToList<Grouping>(); } else return new List<Grouping>(); }

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• How can I add SOAP Headers to a WSDL generated Borland C++ Builder 6 application.

  - by MJG

  Using a WSDL that requires a SOAP HEADER for Authentication (fragment below) code that gets generated when creating a web service client via the "WSDL Importer" has no concept of the Authentication Headers and there are no examples in BCB6 C++ Examples/WebServices directories that show how, and nothing on Web that I can find. Anyone with BCB6 C++ (not Delphi) have an example of adding SOAP Headers to a TRemotable subclass? <s:element name="AuthenticationHeader" type="tns:AuthenticationHeader"/> <s:complexType name="AuthenticationHeader"> <s:complexContent mixed="false"> <s:extension base="tns:UserAuthHeader"> <s:sequence> <s:element minOccurs="0" maxOccurs="1" name="Function" type="s:string"/> <s:element minOccurs="1" maxOccurs="1" name="TimeOutMilliSec" type="s:int"/> </s:sequence> </s:extension> </s:complexContent> </s:complexType> <s:complexType name="UserAuthHeader"> <s:sequence> <s:element minOccurs="0" maxOccurs="1" name="Username" type="s:string"/> <s:element minOccurs="0" maxOccurs="1" name="Password" type="s:string"/> </s:sequence> <s:anyAttribute/> </s:complexType>

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• Custom UITableViewCell from xib isn't displaying properly

  - by Kenny Wyland

  I've created custom UITableCells a bunch of times and I've never run into this problem, so I'm hoping you can help me find the thing I've missed or messed up. When I run my app, the cells in my table view appear to be standard cells with Default style. I have SettingsTableCell which is a subclass of UITableViewCell. I have a SettingsTableCell.xib which contains a UITableViewCell and inside that are a couple labels and a textfield. I've set the class type in the xib to be SettingsTableCell and the File's Owner of the xib to my table controller. My SettingsTableController has an IBOutlet property named tableCell. My cellForRowAtIndexPath contains the following code to load my table view xib and assign it to my table controller's tableCell property: static NSString *CellIdentifier = @"CellSettings"; SettingsTableCell *cell = (SettingsTableCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { [[NSBundle mainBundle] loadNibNamed:@"SettingsTableCell" owner:self options:nil]; cell = self.tableCell; self.tableCell = nil; NSLog(@"cell=%@", cell); } This is what my xib set up looks like in IB: When I run my app, the table displays as if all of the cells are standard Default style cells though: The seriously weird part is though... if I tap on the area of the cell where the textfield SHOULD be, the keyboard does come up! The textfield isn't visible, there's no cursor or anything like that... but it does respond. The visible UILabel is obviously not the UILabel from my xib though because the label in my xib is right justified and the one showing in the app is left justified. I'm incredibly confused about how this is happening. Any help is appreciated.

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• Using Visual Studio 2010 Express to create a surface I can draw to

  - by Joel

  I'm coming from a Java background and trying to port a simple version of Conway's Game of Life that I wrote to C# in order to learn the language. In Java, I drew my output by inheriting from JComponent and overriding paint(). My new canvas class then had an instance of the simulation's backend which it could read/manipulate. I was then able to get the WYSIWYG GUI editor (Matisse, from NetBeans) to allow me to visually place the canvas. In C#, I've gathered that I need to override OnPaint() to draw things, which (as far as I know) requires me to inherit from something (I chose Panel). I can't figure out how to get the Windows forms editor to let me place my custom class. I'm also uncertain about where in the generated code I need to place my class. How can I do this, and is putting all my drawing code into a subclass really how I should be going about this? The lack of easy answers on Google suggests I'm missing something important here. If anyone wants to suggest a method for doing this in WPF as well, I'm curious to hear it. Thanks

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• Memory leak in PHP with Symfony + Doctrine

  - by Nicklas Ansman

  I'm using PHP with the Symfony framework (with Doctrine as my ORM) to build a spider that crawls some sites. My problem is that the following code generates a memory leak: $q = $this -> createQuery('Product p'); if($store) { $q -> andWhere('p.store_id = ?', $store -> getId()) -> limit(1); } $q -> andWhere('p.name = ?', $name); $data = $q -> execute(); $q -> free(true); $data -> free(true); return NULL; This code is placed in a subclass of Doctrine_Table. If I comment out the execute part (and of course the $data - free(true)) the leak stops. This has led me to the conclusion that it's the Doctrine_Collection that's causing the leak. Any ideas on what I can do to fix this? I'd be happy to provide more info on the problem if you need it. Regards Nicklas

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• iPhone SDK: problem managing orientation with multiple view controllers.

  - by Tom

  I'm trying to build an iPhone application that has two subviews in the main window. Each view has its own UIViewController subclass associated with it. Also, within each controller's implementation, I've added the following method: -(BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation { return YES; } Thus, I would expect both of the views to respond to changes in orientation. However, this is not the case. Only the first view added to the app's main window responds to orientation. (If I swap the order the views are added, then only the other view responds. In other words, either will work--but only one at a time.) Why is this? Is it not possible to handle the orientation changes of more than one view? Thanks! EDIT: Someone else had this question, so I'm copying my solution here: I was able to address this issue by providing a root view and a root view controller with the method "shouldAutoRotate..." and adding my other views as subviews to the root view. The subviews inherit the auto-rotating behavior, and their associated view controllers shouldn't need to override "shouldAutoRotate..."

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• Java: refactoring static constants

  - by akf

  We are in the process of refactoring some code. There is a feature that we have developed in one project that we would like to now use in other projects. We are extracting the foundation of this feature and making it a full-fledged project which can then be imported by its current project and others. This effort has been relatively straight-forward but we have one headache. When the framework in question was originally developed, we chose to keep a variety of constant values defined as static fields in a single class. Over time this list of static members grew. The class is used in very many places in our code. In our current refactoring, we will be elevating some of the members of this class to our new framework, but leaving others in place. Our headache is in extracting the foundation members of this class to be used in our new project, and more specifically, how we should address those extracted members in our existing code. We know that we can have our existing Constants class subclass this new project's Constants class and it would inherit all of the parent's static members. This would allow us to effect the change without touching the code that uses these members to change the class name on the static reference. However, the tight coupling inherent in this choice doesn't feel right. before: public class ConstantsA { public static final String CONSTANT1 = "constant.1"; public static final String CONSTANT2 = "constant.2"; public static final String CONSTANT3 = "constant.3"; } after: public class ConstantsA extends ConstantsB { public static final String CONSTANT1 = "constant.1"; } public class ConstantsB { public static final String CONSTANT2 = "constant.2"; public static final String CONSTANT3 = "constant.3"; } In our existing code branch, all of the above would be accessible in this manner: ConstantsA.CONSTANT2 I would like to solicit arguments about whether this is 'acceptable' and/or what the best practices are.

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• Problem setting dynamic UITableViewCell height

  - by HiveHicks

  I've got a UITableView with two dynamic rows. Each of the rows is a subclass of UITableViewCell and is loaded from nib. As my rows contain dynamic content, I use layoutSubviews to reposition all subviews: - (void)layoutSubviews { [super layoutSubviews]; CGFloat initialHeight = titleLabel.bounds.size.height; CGSize constraintSize = CGSizeMake(titleLabel.bounds.size.width, MAXFLOAT); CGSize size = [titleLabel.text sizeWithFont:titleLabel.font constrainedToSize:constraintSize]; CGFloat delta = size.height - initialHeight; CGRect titleFrame = titleLabel.frame; titleFrame.size.height += delta; titleLabel.frame = titleFrame; locationLabel.frame = CGRectOffset(locationLabel.frame, 0, delta); dayLabel.frame = CGRectOffset(dayLabel.frame, 0, delta); timeLabel.frame = CGRectOffset(timeLabel.frame, 0, delta); } The problem is that I can't find a way to determine the height in table view delegate's tableView:heightForRowAtIndexPath: method. The trick is that I load cell from nib, so just after it's loaded titleLabel.bounds.size.width is 300 px (as in nib), not taking into account type of the device (iPhone/iPad) and current orientation, so it seems impossible to calculate the height without conditional checks for orientation and device type. Any ideas?

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• Update a portion UIView

  - by Brett

  Hi; I'm using -setNeedsDisplayinRect to update only a part of my UIView. However, all of my drawing done previously to calling this method is erased. Here is my code in the UIView subclass: -(void)drawRect:(CGRect)rect{ CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetRGBFillColor(context, r, g, b, 1); CGContextSetRGBStrokeColor(context, r, g, b, 1); CGRect arect = CGRectMake(x,y,1,1); CGContextFillRect(context, arect); NSLog(@"drawing"); } and in the view controller: -(void)drawView{ drawingView = [[DrawingView alloc]init]; x=10; y=10; r=0; g=0; b=0; [drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)]; x=20; y=20; r=0; g=0; b=0; [drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)]; } I end up with a screen where there is only one pixel at 20,20. Any help with this is so much appreciated. I am a beginner with XCode and am trying to complete a class project asap.

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• Is there a proper and wrong way to format CSS?

  - by DavidR

  When I first started writing CSS, I was writing it in an expanded form div.class { margin: 10px 5px 3px; border: 1px solid #333; font-weight: bold; } .class .subclass { text-align:right; } but now I find myself writing css like this: (Example from code I'm actually writing now) .object1 {} .scrollButton{width:44px;height:135px;} .scrollButton img {padding:51px 0 0 23px;} .object2 {width:165px;height:94px;margin:15px 0 0 23px;padding:15px 0 0 10px;background:#fff;} .featuredObject .symbol{line-height:30px; padding-top:6px;} .featuredObject .value {width:90px;} .featuredObject .valueChange {padding:5px 0 0 0;} .featuredObject img {position:absolute;margin:32px 0 0 107px;} and I'm beginning to worry because a lot of the time I see the first form done in examples online, while I find the second form a lot easier for me to work with. It has a lower vertical height, so I can see all the classes at a glance with less scrolling, the tabulation of the hierarchy seems more apparent, and it looks more like code I'd write with javascript or html. Is this a valid way of doing code, or to keep with standards when putting it online should I use the vertical form instead?

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• C As Principal Class For Mac App

  - by CodaFi

  So, I've got a c file raring to go and be the main class behind an all-C mac-app, however, a combination of limiting factors are preventing the application from being launched. As it currently stands, the project is just a main.m and a class called AppDelegate.c, so I entered "AppDelegate" as the name of the principal class in the info.plist, and to my complete surprise, the log printed: Unable to find class: AppDelegate, exiting This would work perfectly well in iOS, because the main function accepts the name of a delegate class, and handles it automatically, but NSApplicationMain() takes no such argument. Now, I know this stems from the fact that there are no @interface/@implementation directives in C, and that's really what the OS seems to be looking for, so I wrote a simple NSApplication subclass and provided it as the Principal Class to the plist, and it launched perfectly well. My question is, how could one go about setting a c file as the principal class in a mac application and have it launch correctly? PS, don't ask what or why I'm doing this for, the foundation must be dug. For @millimoose's amusement, here be the AppDelegate.c file: #include <objc/runtime.h> #include <objc/message.h> struct AppDel { Class isa; id window; }; // This is a strong reference to the class of the AppDelegate // (same as [AppDelegate class]) Class AppDelClass; BOOL AppDel_didFinishLaunching(struct AppDel *self, SEL _cmd, void *application, void *options) { self->window = objc_msgSend(objc_getClass("NSWindow"), sel_getUid("alloc")); self->window = objc_msgSend(self->window, sel_getUid("init")); objc_msgSend(self->window, sel_getUid("makeKeyAndOrderFront:"), self); return YES; }

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• Getting a particular menu item from MainMenu

  - by Garry

  I have a nib (winA.xib) that contains a window. My app delegate contains an NSWindowController subclass called WinAController. WinAController has a property (NSMenu *mainMenu) that I want to point to the MainMenu. I have set it after I instantiate WinAController with this code: WinAController = [[WinAController alloc] initWithWindowNibName:@"WinA"]; WinAController.mainMenu = [NSApp mainMenu]; I have a menu item underneath the "Window" top-level menu item on MainMenu that invokes the [WinAController showWindow] method and displays WinA. I want to toggle the on/off state of this menu item depending on whether WinA is visible or not. WinAController also has another property (NSMenuItem *myMenuItem). How can I get a reference to a sub menu of the "Window" top-level menu item. The title of sub menu item I want to get is "Command". I have tried this: if (mainMenu != nil) { myMenuItem = [mainMenu itemAtIndex:[mainMenu indexOfItemWithTitle:@"Command"]]; } But it doesn't seem to work. Where am I going wrong? Thanks,

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• How do I access abstract private data from derived class without friend or 'getter' functions in C++?

  - by John

  So, I am caught up in a dilemma right now. How am I suppose to access a pure abstract base class private member variable from a derived class? I have heard from a friend that it is possible to access it through the base constructor, but he didn't explain. How is it possible? There are some inherited classes from base class. Is there any way to gain access to the private variables ? class Base_button { private: bool is_vis; Rect rButton; public: // Constructors Base_button(); Base_button( const Point &corner, double height, double width ); // Destructor virtual ~ Base_button(); // Accessors virtual void draw() const = 0; bool clicked( const Point &click ) const; bool is_visible() const; // Mutators virtual void show(); virtual void hide(); void move( const Point &loc ); }; class Button : public Base_button { private: Message mButton; public: // Constructors Button(); Button( const Point &corner, const string &label ); // Acessors virtual void draw() const; // Mutators virtual void show(); virtual void hide(); }; I want to be able access Rect and bool in the base class from the subclass

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• Interesting Scala typing solution, doesn't work in 2.7.7?

  - by djc

  I'm trying to build some image algebra code that can work with images (basically a linear pixel buffer + dimensions) that have different types for the pixel. To get this to work, I've defined a parametrized Pixel trait with a few methods that should be able to get used with any Pixel subclass. (For now, I'm only interested in operations that work on the same Pixel type.) Here it is: trait Pixel[T <: Pixel[T]] { def mul(v: Double): T def max(v: T): T def div(v: Double): T def div(v: T): T } Now I define a single Pixel type that has storage based on three doubles (basically RGB 0.0-1.0), I've called it TripleDoublePixel: class TripleDoublePixel(v: Array[Double]) extends Pixel[TripleDoublePixel] { var data: Array[Double] = v def this() = this(Array(0.0, 0.0, 0.0)) def toString(): String = { "(" + data(0) + ", " + data(1) + ", " + data(2) + ")" } def increment(v: TripleDoublePixel) { data(0) += v.data(0) data(1) += v.data(1) data(2) += v.data(2) } def mul(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x * v)) } def div(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x / v)) } def div(v: TripleDoublePixel): TripleDoublePixel = { var tmp = new Array[Double](3) tmp(0) = data(0) / v.data(0) tmp(1) = data(1) / v.data(1) tmp(2) = data(2) / v.data(2) new TripleDoublePixel(tmp) } def max(v: TripleDoublePixel): TripleDoublePixel = { val lv = data(0) * data(0) + data(1) * data(1) + data(2) * data(2) val vv = v.data(0) * v.data(0) + v.data(1) * v.data(1) + v.data(2) * v.data(2) if (lv > vv) (this) else v } } Now I want to write code to use this, that doesn't have to know what type the pixels are. For example: def idiv[T](a: Image[T], b: Image[T]) { for (i <- 0 until a.data.size) { a.data(i) = a.data(i).div(b.data(i)) } } Unfortunately, this doesn't compile: (fragment of lindet-gen.scala):145: error: value div is not a member of T a.data(i) = a.data(i).div(b.data(i)) I was told in #scala that this worked for someone else, but that was on 2.8. I've tried to get 2.8-rc1 going, but it doesn't compile for me. Is there any way to get this to work in 2.7.7?

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• Is it OK to set state within Event Raising methods?

  - by Greg

  I ran across this pattern in the code of a library I'm using. It sets state within the event raising method, but only if the event is not null. protected virtual void OnMyEvent(EventArgs e) { if(MyEvent != null) { State = "Executing"; // Only sets state if MyEvent != null. MyEvent(this,e); } } Which means that the state is not set when overriding the method: protected override void OnMyEvent(EventArgs e) { base.OnMyEvent(e); Debug.Assert( State == "Executing" ); // This fails } but is only set when handling the event: foo.MyEvent += (o, args) => Debug.Assert(State == "Executing"); // This passes Setting state within the if(MyEvent != null) seems like bad form, but I've checked the Event Design Guidelines and it doesn't mention this. Do you think this code is incorrect? If so, why? (Reference to design guidelines would be helpful). Edit for Context: It's a Control, I'm trying to create subclass of it, and the state that it's setting is calling EnsureChildControls() conditionally based upon there being an event handler. I can call EnsureChildControls() myself, but I consider that something of a hack.

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• Implementations details of drag and drop of file path in cocoa.

  - by foo

  Hi, I'm trying to get a part of my window to react to drag and drop. In this case to copy the file path to the file being dropped on the view. I have looked over some documentation but I still have some problems to see exactly where I should implement my methods for drag and drop. I have seen some examples but almost all of them assumes that I want to drop an image on the view. I'm pretty new to cocoa and Xcode so, I have some problems with seeing the exact relation between interface builder and the generated code. I have created a subclass to NSView, called drop zone like this: #import <Cocoa/Cocoa.h> @interface dropZone : NSView { } @end I then use an NSRect to color it grey like this: #import "dropZone.h" @implementation dropZone - (void)drawRect:(NSRect)rect { NSRect bounds = [self bounds]; [[NSColor grayColor] set]; [NSBezierPath fillRect:bounds]; } @end I then drag this class to my window in interface builder. But I will need to implement the registerForDraggingTypes method, but where? I have also seen a convenience method in the Apple docs for file paths like this: dragFile:fromRect:slideBack:event: that might work.

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• In Python, how to make data members visible to subclasses if not known when initializing an object ?

  - by LB

  The title is a bit long, but it should be pretty straightforward for someone well-aware of python. I'm a python newbie. So, maybe i'm doing things in the wrong way. Suppose I have a class TreeNode class TreeNode(Node): def __init__(self, name, id): Node.__init__(self, name, id) self.children = [] and a subclass with a weight: class WeightedNode(TreeNode): def __init__(self,name, id): TreeNode.__init__(self, name, id) self.weight = 0 So far, i think I'm ok. Now, I want to add an object variable called father in TreeNode so that WeightedNode has also this member. The problem is that I don't know when initializing the object who is going to be the father. I set the father afterwards with this method in TreeNode : def set_father(self, father_node): self.father = father_node The problem is then when i'm trying to access self.father in Weighted: print 'Name %s Father %s '%(self.name, self.father.name) I obtain: AttributeError: WeightedNode instance has no attribute 'father' I thought that I could make father visible by doing something in TreeNode.__init__ but i wasn't able to find what. How can i do that ? Thanks.

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• How to call a method after asynchronous task is complete

  - by doctordoder

  I have a class called WikiWebView which is a subclass of UIWebView which loads Wikipedia subjects and is designed to fetch all the links of the webpage, in order to create a sort of site map for the subject. My problem is that I can only create the links once the web page has loaded, but the loading isn't done right after [self loadRequest:requestObj] is called. - (void)loadSubject:(NSString *)subject { // load the actual webpage NSString *wiki = @"http://www.wikipedia.org/wiki/"; NSString *fullURL = [wiki stringByAppendingString:subject]; NSURL *url = [NSURL URLWithString:fullURL]; NSURLRequest *requestObj = [NSURLRequest requestWithURL:url]; [self loadRequest:requestObj]; // [self createLinks]; // need this to be called after the view has loaded } - (void)createLinks { NSString *javascript = @"var string = \"\";" "var arr = document.getElementsByClassName(\"mw-redirect\");" "for (var i = 0; i < arr.length; ++i)" "{" "var redirectLink = arr[i].href;" "string = string + redirectLink + \" \";" "}" "string;"; NSString *links = [self stringByEvaluatingJavaScriptFromString:javascript]; self.links = [links componentsSeparatedByString:@" "]; } I tried the normal delegation technique, which lead to this code being added: - (id)init { if (self = [super init]) { self.delegate = self; // weird } return self; } #pragma mark - UIWebViewDelegate - (void)webViewDidStartLoad:(UIWebView *)webView { ++_numProcesses; } - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error { --_numProcesses; } - (void)webViewDidFinishLoad:(UIWebView *)webView { --_numProcesses; if (_numProcesses == 0) { [self createLinks]; } } However, the delegate methods are never called.. I've seen similar questions where the answers are to use blocks, but how would I do that in this case?

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• Forcing size of a complex Flash object.

  - by John

  As I've found recently, setting width/height properties on a Sprite only forces the Sprite to fit the given dimensions by scaling the actual size, which is calculated by Flash based on the rendered content. This leaves me confused. If I have a custom Sprite subclass which draws using Graphics, how can I do layout before an initial render - the size will be zero until it is first drawn? For a more complex issue, let's say I have a 2D game world with objects spread over a wide area with world coordinates from (0,0) to (5000,5000), where each object has a size of maybe up to 100x100. I want to have a Flash component which is the "game window", and has a fixed size like 400x300, rendering part of the game world. So how do I force the game window size to 400x300 pixels? I can draw a 400x300 rectangle to get the size correct but then if I draw any objects which are partly in-view, they can screw this up. Is the right approach to provide a custom setSize(w,h) method which is used rather than width & height setters? But even so, is there no way to make a Sprite force to the size I want? Do you really have to catch it every render and re-scale it?

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• Is there any seriously good reason why a view can not completely manage itself?

  - by mystify

  Example: I have an warning triangle icon, which is a UIImageView subclass. That warning is blended in with an animation, pulses for 3 seconds and then fades out. it always has a parent view! it's always only used this way: alloc, init, add as subview, kick off animation, when done:remove from superview So I want this: [WarningIcon warningAtPosition:CGPointMake(50.0f, 100.0f) parentView:self]; BANG! That's it. Call and forget. The view adds itself as subview to the parent, then does it's animations. And when done, it cuts itself off from the branch with [self removeFromSupeview];. Now some nerd a year ago told me: "Never cut yourself off from your own branch". In other words: A view should never ever remove itself from superview if it's no more referenced anywhere. I want to get it, really. WHY? Think about this: The hard way, I would do actually the exact same thing. Create an instance and hang me in as delegate, kick off the animation, and when the warning icon is done animating, it calls me back "hey man i'm done, get rid of me!" - so my delegate method is called with an pointer to that instance, and I do the exact same thing: [thatWarningIcon removeFromSuperview]; - BANG. Now I'd really love to know why this sucks. Life would be so easy.

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• Frame sizing of tableview within nested child controllers/subviews

  - by jwoww

  I'm a bit confused by the proper frame sizing of a table view to fit within my screen. Here's my setup of view controllers within view controllers: UITabBarController UINavigationController as one of the tab bar viewcontrollers; title bar hidden ViewController - a container view controller because I need the option to place some controls beneath the UITableView, sometimes (but not in the current scenario) UITableViewController Now, my question is what the proper frame dimensions of the UITableview should be. Here's what I've got in the ViewController viewDidLoad method. I used subtracted 49.0 (the size of the tab bar) from 480.0. However, this leaves a black bar at the bottom. 20.0 appears to do it (coincidentally?) the size of the status bar, but I don't understand why that would be. Wouldn't the true pixel dimensions of the tableview be 480-49? // MessageTableViewController is my subclass of UITableViewController MessagesTableViewController *vcMessagesTable = [[MessagesTableViewController alloc] init]; CGRect tableViewFrame = CGRectMake(0, 0, 320.0, 480.0 - 49.0); [[vcMessagesTable view] setFrame:tableViewFrame]; self.tableViewController = vcMessagesTable; [self addChildViewController:vcMessagesTable]; [[self view] addSubview:vcMessagesTable.view]; Here's how it looks:

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