Search Results

Search found 17921 results on 717 pages for 'cocoa design patterns'.

Page 34/717 | < Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >

• Clean bindings with structs

  - by andyvn22

  I have a model class for which it makes quite a lot of sense to have NSSize and NSPoint instance variables. This is lovely. I'm trying to create an editing interface for this object. I'd like to bind to size.width and whatnot. This, of course, doesn't work. What's the cleanest, most Cocoa-y solution to this problem? Of course I could write separate accessors for the individual members of every struct I use, but it seems like there should be a better solution.

  Read the article

• Looking for marg_setValue fix in iPhoneOS

  - by John Smith

  I am trying to compile a library originally written for Cocoa. Things are good until it looks for the function marg_setValue(). It says there is a syntax error before char in marg_setValue(argumentList,argumentOffset,char,(char)lua_toboolean(state,luaArgument)); (it's talking about the third argument, not (char) ) I am trying to port LuaObjectiveCBridge to the iPhone. It has two choices, either using Runtime or Foundation. I have discovered there are some problems with foundation so I am trying runtime. But the compiler is not co-operating.

  Read the article

• Cocoa memory management - object going nil on me

  - by SirRatty

  Hi all, Mac OS X 10.6, Cocoa project, with retain/release gc I've got a function which: iterates over a specific directory, scans it for subfolders (included nested ones), builds an NSMutableArray of strings (one string per found subfolder path), and returns that array. e.g. (error handling removed for brevity). NSMutableArray * ListAllSubFoldersForFolderPath(NSString *folderPath) { NSMutableArray *a = [NSMutableArray arrayWithCapacity:100]; NSString *itemName = nil; NSFileManager *fm = [NSFileManager defaultManager]; NSDirectoryEnumerator *e = [fm enumeratorAtPath:folderPath]; while (itemName = [e nextObject]) { NSString *fullPath = [folderPath stringByAppendingPathComponent:itemName]; BOOL isDirectory; if ([fm fileExistsAtPath:fullPath isDirectory:&isDirectory]) { if (isDirectory is_eq YES) { [a addObject: fullPath]; } } } return a; } The calling function takes the array just once per session, keeps it around for later processing: static NSMutableArray *gFolderPaths = nil; ... gFolderPaths = ListAllSubFoldersForFolderPath(myPath); [gFolderPaths retain]; All appears good at this stage. [gFolderPaths count] returns the correct number of paths found, and [gFolderPaths description] prints out all the correct path names. The problem: When I go to use gFolderPaths later (say, the next run through my event loop) my assertion code (and gdb in Xcode) tells me that it is nil. I am not modifying gFolderPaths in any way after that initial grab, so I am presuming that my memory management is screwed and that gFolderPaths is being released by the runtime. My assumptions/presumptions I do not have to retain each string as I add it to the mutable array because that is done automatically, but I do have to retain the the array once it is handed over to me from the function, because I won't be using it immediately. Is this correct? Any help is appreciated.

  Read the article

• Cocoa button won't display image

  - by A Mann

  Just started exploring Cocoa so pretty much a total noob. I've written a very simple game. Set it up in Interface Builder and got it working fine. It contains a number of buttons and I'm now trying to get the buttons to display images. To start with I'm trying to get an image displayed on just one of the buttons which is called tile0 . The image file (it's nothing but a green square at the moment, but I'm just trying to get that working before I attempt anything more exotic) is sitting in the same directory as the class file which controls the game. I have the following code sitting in my wakeFromNib method: NSString *myImageFileName = [[NSString alloc] init]; myImageFileName = @"greenImage.jpg"; NSImage *myImage = [[NSImage alloc] initByReferencingFile:myImageFileName]; [tile0 setImage: myImage]; Trouble is, the game runs fine, but the image isn't appearing on my button. Is there someone who could kindly tell me if I'm doing something obviously wrong? Many Thanks.

  Read the article

• COCOA: Programatically creating new windows and accessing window objects

  - by Jeffrey Kern

  I'm having an issue with creating new windows in Cocoa. Hypothetically speaking, lets say I have "WindowA" and has a button called "myButton". When you click on "myButton", it runs this code in the following class file: -(void)openFile2:(id)sender { myNextWindow = [[TestWindowController alloc] initWithWindowNibName:@"MainMenu"]; NSString *testString = @"foo"; [myNextWindow showWindow:self]; [myNextWindow setButtonText:testString]; } The code in a nutshell makes a duplicate "WindowA" and shows it. As you can see, this code also runs a method called 'setButtonText', which is this: - (void)setButtonText:(NSString *)passedText { [myButton setTitle:passedText]; } The problem is that when I call this method locally, in the original window - the button text changes (e.g., [self setButtonText:testString]) it works. However, it does not work in the newly created window (e.g., [myNextWindow setButtonText:testString];) When I debug the newly created window, step by step, the 'myButton' value it gives is 0x0. Do I have to manually assign controllers/delegates to the new window? I think the 'myButton' in the code isn't associated to the 'myButton' in the newly created window. How would I fix this problem?

  Read the article

• What should you do differently when designing websites for an embedded web server

  - by Roger Attrill

  When designing a website to be accessed from an embedded webserver such as KLone, what do you need to do differently compared to a 'standard' web server. I'm talking about considerations at the front end design stage, before the actual building and coding up. For example, typically in such situations, memory size is a premium, so I guess larger images are out, and maybe more attention should be focused on achieving a good look and feel using CSS/Javascript rather than bitmap images.

  Read the article

• What is the greatest design flaw you have faced in any programming language?

  - by Anto

  All programming languages are having their design flaws simply because not a single language can be perfect, just as with most (all?) other things. That aside, which design fault in a programming language has annoyed you the most through your history as a programmer? Note that if a language is "bad" just because it isn't designed for a specific thing isn't a design flaw, but a feature of design, so don't list such annoyances of languages. If a language is illsuited for what it is designed for, that is of course a flaw in the design. Implementation specific things and under the hood things do not count either.

  Read the article

• How does a search functionality fit in DDD with CQRS?

  - by Songo

  In Vaughn Vernon's book Implementing domain driven design and the accompanying sample application I found that he implemented a CQRS approach to the iddd_collaboration bounded context. He presents the following classes in the application service layer: CalendarApplicationService.java CalendarEntryApplicationService.java CalendarEntryQueryService.java CalendarQueryService.java I'm interested to know if an application will have a search page that feature numerous drop downs and check boxes with a smart text box to match different search patterns; How will you structure all that search logic? In a command service or a query service? Taking a look at the CalendarQueryService.java I can see that it has 2 methods for a huge query, but no logic at all to mix and match any search filters for example. I've heard that the application layer shouldn't have any business logic, so where will I construct my dynamic query? or maybe just clutter everything in the Query service?

  Read the article

• Programming habits, patterns, and standards that have developed out of appeal to tradition/by mistake? [closed]

  - by user828584

  Being self-taught, the vast majority of what I know about programming has come from reading other peoples' code on websites like this. I'm starting to wonder if I've developed bad or otherwise pointless habits from other people, or even just made invalid assumptions. For example, in javascript, void 0 is used in a lot of places, and until I saw this, I just assumed it was necessary and that 0 had some significance. Also, the http header, referer is misspelled but hasn't been changed because it would break a lot of applications. Also mentioned in Code Complete 2: The architecture should describe the motivations for all major decisions. Be wary of “we’ve always done it that way” justifications. One story goes that Beth wanted to cook a pot roast according to an award-winning pot roast recipe handed down in her husband’s family. Her husband, Abdul, said that his mother had taught him to sprinkle it with salt and pepper, cut both ends off, put it in the pan, cover it, and cook it. Beth asked, “Why do you cut both ends off?” Abdul said, “I don’t know. I’ve always done it that way. Let me ask my mother.” He called her, and she said, “I don’t know. I’ve always done it that way. Let me ask your grandmother.” She called his grandmother, who said, “I don’t know why you do it that way. I did it that way because it was too big to fit in my pan.” What are some other examples of this?

  Read the article

• In PHP, what are the different design patterns to implement OO controllers as opposed to procedural controllers?

  - by Ryan

  For example, it's very straightforward to have an index.php controller be a procedural script like so: <?php //include classes and functions //get some data from the database //and/or process a form submission //render HTML using your template system ?> Then I can just navigate to http://mysite.com/index.php and the above procedural script is essentially acting as a simple controller. Here the controller mechanism is a basic procedural script. How then do you make controllers classes instead of procedural scripts? Must the controller class always be tied to the routing mechanism?

  Read the article

• Patterns for a tree of persistent data with multiple storage options?

  - by Robin Winslow

  I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access parents: // Interfaces interface IParent<TChild> { List<TChild> Children; } interface IChild<TParent> { TParent Parent; } // Classes class Top : IParent<Middle> {} class Middle : IParent<Bottom>, IChild<Top> {} class Bottom : IChild<Middle> {} // Usage var top = new Top(); var middles = top.Children; // List<Middle> foreach (var middle in middles) { var bottoms = middle.Children; // List<Bottom> foreach (var bottom in bottoms) { var middle = bottom.Parent; // Access the parent var top = middle.Parent; // Access the grandparent } } All three data objects have properties that are persisted in two data stores (e.g. a database and a web service), and they need to reflect and synchronise with the stores. Some objects only request from the web service, some only write to it. Data Mapper My favourite pattern for data access is Data Mapper, because it completely separates the data objects themselves from the communication with the data store: class TopMapper { public Top FetchById(int id) { var top = new Top(DataStore.TopDataById(id)); top.Children = MiddleMapper.FetchForTop(Top); return Top; } } class MiddleMapper { public Middle FetchById(int id) { var middle = new Middle(DataStore.MiddleDataById(id)); middle.Parent = TopMapper.FetchForMiddle(middle); middle.Children = BottomMapper.FetchForMiddle(bottom); return middle; } } This way I can have one mapper per data store, and build the object from the mapper I want, and then save it back using the mapper I want. There is a circular reference here, but I guess that's not a problem because most languages can just store memory references to the objects, so there won't actually be infinite data. The problem with this is that every time I want to construct a new Top, Middle or Bottom, it needs to build the entire object tree within that object's Parent or Children property, with all the data store requests and memory usage that that entails. And in real life my tree is much bigger than the one represented here, so that's a problem. Requests in the object In this the objects request their Parents and Children themselves: class Middle { private List<Bottom> _children = null; // cache public List<Bottom> Children { get { _children = _children ?? BottomMapper.FetchForMiddle(this); return _children; } set { BottomMapper.UpdateForMiddle(this, value); _children = value; } } } I think this is an example of the repository pattern. Is that correct? This solution seems neat - the data only gets requested from the data store when you need it, and thereafter it's stored in the object if you want to request it again, avoiding a further request. However, I have two different data sources. There's a database, but there's also a web service, and I need to be able to create an object from the web service and save it back to the database and then request it again from the database and update the web service. This also makes me uneasy because the data objects themselves are no longer ignorant of the data source. We've introduced a new dependency, not to mention a circular dependency, making it harder to test. And the objects now mask their communication with the database. Other solutions Are there any other solutions which could take care of the multiple stores problem but also mean that I don't need to build / request all the data every time?

  Read the article

• What patterns book for iOS development contains this specific information? [closed]

  - by Brett Ryan

  I've read several books on iOS development and Objective-C, however what a lot of them teach is how to work with interfaces and all contain the model inside the view controller, i.e. a UITableViewController based view will simply have an NSArray as it's model. I'm interested in what the best practices are for designing the structure of an application. Specifically I'm interested in best practices for the following: How to separate a model from the view controller. I think I know how to do this by simply replacing the NSArray style example with a specific model object, however what I do not know how to do is alert the view when the model changes. For example in .NET I would solve this by conforming to INotifyPropertyChanged and databinding, and similarly with Java I would use PropertyChangeListener. How to create a service model for my domain objects. For example I want to learn the best way to create a service for a hypothetical Widget object to manage an internal DB and also services for communicating with remote endpoints. I need to learn the best ways to do this in a way that interface components can subscribe to events such as widgetUpdated. These services should be singleton classes and some how dependency injected into model/controller objects. Books I've read so far are: Programming in Objective-C (4th Edition) Beginning iOS 5 Development: Exploring the iOS SDK The iOS 5 Developer's Cookbook: Expanded Electronic Edition: Essentials and Advanced Recipes for iOS Programmers Learn Objective-C on the Mac: For OS X and iOS I've also purchased the following updated books but not yet read them. The Core iOS 6 Developer's Cookbook (4th edition Programming in Objective-C (5th Edition) I come from a Java and C# background with 15 years experience, I understand that many of the ways I would do things in these languages may not fit to the ObjC way of developing applications. Would someone be able to provide me with the book on this topic containing this specific subject matter?

  Read the article

• Design pattern: static function call with input/output containers?

  - by Pavlo Dyban

  I work for a company in software research department. We use algorithms from our real software and wrap them so that we can use them for prototyping. Every time an algorithm interface changes, we need to adapt our wrappers respectively. Recently all algorithms have been refactored in such a manner that instead of accepting many different inputs and returning outputs via referenced parameters, they now accept one input data container and one output data container (the latter is passed by reference). Algorithm interface is limited to a static function call like that: class MyAlgorithm{ static bool calculate(MyAlgorithmInput input, MyAlgorithmOutput &output); } This is actually a very powerful design, though I have never seen it in a C++ programming environment before. Changes in the number of parameters and their data types are now encapsulated and they don't change the algorithm callback. In the latest algorithm which I have developed I used the same scheme. Now I want to know if this is a popular design pattern and what it is called.

  Read the article

• Mutability design patterns in Objective C and C++

  - by Mac

  Having recently done some development for iPhone, I've come to notice an interesting design pattern used a lot in the iPhone SDK, regarding object mutability. It seems the typical approach there is to define an immutable class NSFoo, and then derive from it a mutable descendant NSMutableFoo. Generally, the NSFoo class defines data members, getters and read-only operations, and the derived NSMutableFoo adds on setters and mutating operations. Being more familiar with C++, I couldn't help but notice that this seems to be a complete opposite to what I'd do when writing the same code in C++. While you certainly could take that approach, it seems to me that a more concise approach is to create a single Foo class, mark getters and read-only operations as const functions, and also implement the mutable operations and setters in the same class. You would then end up with a mutable class, but the types Foo const*, Foo const& etc all are effectively the immutable equivalent. I guess my question is, does my take on the situation make sense? I understand why Objective-C does things differently, but are there any advantages to the two-class approach in C++ that I've missed? Or am I missing the point entirely? Not an overly serious question - more for my own curiosity than anything else.

  Read the article

• OO Design / Patterns - Fat Model Vs Transaction Script?

  - by ben

  Ok, 'Fat' Model and Transaction Script both solve design problems associated with where to keep business logic. I've done some research and popular thought says having all business logic encapsulated within the model is the way to go (mainly since Transaction Script can become really complex and often results in code duplication). However, how does this work if I want to use the TDG of a second Model in my business logic? Surely Transaction Script presents a neater, less coupled solution than using one Model inside the business logic of another? A practical example... I have two classes: User & Alert. When pushing User instances to the database (eg, creating new user accounts), there is a business rule that requires inserting some default Alerts records too (eg, a default 'welcome to the system' message etc). I see two options here: 1) Add this rule as a User method, and in the process create a dependency between User and Alert (or, at least, Alert's Table Data Gateway). 2) Use a Transaction Script, which avoids the dependency between models. (Also, means the business logic is kept in a 'neutral' class & easily accessible by Alert. That probably isn't too important here, though). User takes responsibility for it's own validation etc, however, but because we're talking about a business rule involving two Models, Transaction Script seems like a better choice to me. Anyone spot flaws with this approach?

  Read the article

• Tablet design guide, Endeca patterns now available

  - by JuergenKress

  UX Direct, an Oracle program that offers consultants, partners, and customers the same scientifically proven and reusable user experience best practices that Oracle uses to build Oracle Applications, recently added links to a new design guide for creating tablet-based solutions for enterprise applications, and to the recently published Endeca User Interface Design Pattern Library. The tablet design guide is available from the UX Direct Home page. Tap the button under “Latest patterns & tools” for “Oracle Applications UX Tablet Guide.” It provides basic help for designers, developers, and project managers trying to approach tablet design and testing from an enterprise point of view. To hear what developers are saying about it, follow the links from this post on the User Experience Assistance blog. The newly released Endeca User Interface Design Pattern Library is also available from the UX Direct Home page and from a post on the User Experience Assistance blog. It describes principled ways to solve common user interface (UI) design problems related to search, faceted navigation, and discovery. The link between Simplified UI and Oracle UX strategy, plus content you can share on the cloud, ADf, tailoring, and more Simplified User Interface in Oracle Fusion Applications Fronts Oracle Cloud Offerings This new article on Simplified UI has just been posted on Usable Apps. Learn about the three themes - simplicity, mobility, and extensibility – that Simplified UI embodies. These same principles are guiding the development of the next generation of the Oracle user experience. Oracle's Applications User Experience Strategy: One Cloud User Experience, with Optimized UIs Where and How You Want This podcast from Misha Vaughan, Director, User Experience, is now available on the Oracle University Knowledge Center. It is available for partners and Oracle employees at this iLearning Link. Oracle Partner Builds User Experience That Hits Right Note for New Employees This new article on the Usable Apps website explores the experience of consultants at IntraSee as they implement a PeopleSoft onboarding process for Invesco, a global asset management company. The Feng Shui of Fusion This article in Oracle Scene is from Grant Ronald, Director of Product Management, on the Tools of Fusion: Oracle JDeveloper and Oracle ADF. Hands-On Workshop with Fusion Applications and ADF UX Desktop Design Patterns This post on the Voice of User Experience, or VoX, blog from Misha Vaughan describes a new kind of workshop for partners and a handful of internal Oracle sales folks on extending Oracle Fusion Applications and building custom applications with Application Development Framework (ADF) while maintaining the Oracle user experience. To learn more about the content that was delivered during this three-day workshop, visit the Usable Apps blog. Recent posts from a new blog series take a look at several of the topics discussed during the workshop. Applications User Experience Fundamentals Visual Design for any Enterprise User Interface / Art School in a Box Wireframing / Blueprinting Usable Applications Concepts. Tailoring videos This blog post from Richard Bingham, Applications Architect, on the Fusion Applications Developer Relations blog provides links to several videos that show many customization and development tasks using the Oracle Fusion Applications platform. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: UX,Architecture,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

  Read the article

• get current selected button cell placed inside tableview using cocoa

  - by Swati

  hi i have a NSTableView i have two columns A and B B contains some data A contains custom button the button is added to column A using this: Below code is placed inside awakeFromNib method NSButtonCell *buttonCell = [[[NSButtonCell alloc] init] autorelease]; [buttonCell setBordered:NO]; [buttonCell setImagePosition:NSImageOnly]; [buttonCell setButtonType:NSMomentaryChangeButton]; [buttonCell setImage:[NSImage imageNamed:@"uncheck.png"]]; [buttonCell setSelectable:TRUE]; [buttonCell setTag:100]; [buttonCell setTarget:self]; [buttonCell setAction:@selector(selectButtonsForDeletion:)]; [[myTable tableColumnWithIdentifier:@"EditIdentifier"] setDataCell:buttonCell]; Some code in display cell of nstableview: -(void)tableView:(NSTableView *)tableView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)rowIndex { if(tableView == myTable) { if([[tableColumn identifier] isEqualToString:@"DataIdentifier"]) { } else if([[tableColumn identifier] isEqualToString:@"EditIdentifier"]) { NSButtonCell *zCell = (NSButtonCell *)cell; [zCell setTag:rowIndex]; [zCell setTitle:@"abc"]; [zCell setTarget:self]; [zCell setAction:@selector(selectButtonsForDeletion:)]; } } } now i want that when i click on the button the image of button cell gets changed as well as i want to do some coding. When button gets clicked then by default the tableView's reference gets passed. How can i get the button cell reference i looked here for similar problem: Cocoa: how to nest a button inside a Table View cell? but i am unable to add button inside column of NSTableView. How i change the image: - (void)tableView:(NSTableView *)tableView setObjectValue:(id)object forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row; { if(tableView == myTable) { if([[tableColumn identifier] isEqualToString:@"EditIdentifier"]) { NSButtonCell *aCell = (NSButtonCell *)[[tableView tableColumnWithIdentifier:@"EditIdentifier"] dataCellForRow:row]; NSInteger index = [[aCell title]intValue]; if([self.selectedIndexesArray count]>0) { if(![self.selectedIndexesArray containsObject:[NSNumber numberWithInt:index]]) { [aCell setImage:[NSImage imageNamed:@"check.png"]]; [self.selectedIndexesArray addObject:[NSNumber numberWithInt:index]]; } else { [aCell setImage:[NSImage imageNamed:@"uncheck.png"]]; [self.selectedIndexesArray removeObjectAtIndex:[selectedIndexesArray indexOfObject:[NSNumber numberWithInt:index]]]; } } else { [aCell setImage:[NSImage imageNamed:@"check.png"]]; [self.selectedIndexesArray addObject:[NSNumber numberWithInt:index]]; } } } } I have debugged the code and found that proper tag and titles are passed but image applies on more than one button cell, this is too very irregular. cant understand how its working!!! Any suggestions what am i doing wrong??

  Read the article

• Cocoa NSOutputStream send to a connection

  - by Chuck

  Hi, I am new to Cocoa, but managed to get a connection (to a FTP) up and running, and I've set up an eventhandler for the NSInputStream iStream to alert every response (which also works). What I manage to get is simply the hello message and a connection timeout 60 sec, closing control connection. After searching stackoverflow and finding a lot of NSOutputStream write problems (e.g. http://stackoverflow.com/questions/703729/how-to-use-nsoutputstreams-write-message) and a lot of confusion in my google hits, I figured I'd try to ask my own question: I've tried reading the developer.apple.com doc on OutputStream, but it seems almost impossible for me to send some data (in this case just a string) to the "connection" via the NSOutputStream oStream. - (IBAction) send_something: sender { const char *send_command_char = [@"USER foo" UTF8String]; send_command_buffer = [NSMutableData dataWithBytes:send_command_char length:strlen(send_command_char) + 1]; uint8_t *readBytes = (uint8_t *)[send_command_buffer mutableBytes]; NSInteger byteIndex = 0; readBytes += byteIndex; int data_len = [send_command_buffer length]; unsigned int len = ((data_len - byteIndex >= 1024) ? 1024 : (data_len-byteIndex)); uint8_t buf[len]; (void)memcpy(buf, readBytes, len); len = [oStream write:(const uint8_t *)buf maxLength:len]; byteIndex += len; } the above seems not to result in any useable events. typing it under NSStreamEventHasSpaceAvailable sometimes give a response if I spam the ftp by keep creating new connection instances and keep sending some command whenever oStream has free space. In other words, nothing "right" and so I'm still unclear how to properly send a command to the connection. Should I open - write - close every time i want to write to oStream (and thus to the ftp) and can I then expect a reply (hasBytesAvailable event on iStream)? For some reason I find it very difficult to find any clear tutorials on this matter. Seems like there are more than a few in the same position as me: unclear how to use oStream write? Any little bit that can help clear this up is greatly appreciated! If needed I can write the rest of the code. Chuck

  Read the article

• Game logic dynamically extendable architecture implementation patterns

  - by Vlad

  When coding games there are a lot of cases when you need to inject your logic into existing class dynamically and without making unnecessary dependencies. For an example I have a Rabbit which can be affected by freeze ability so it can't jump. It could be implemented like this: class Rabbit { public bool CanJump { get; set; } void Jump() { if (!CanJump) return; ... } } But If I have more than one ability that can prevent it from jumping? I can't just set one property because some circumstances can be activated simultanously. Another solution? class Rabbit { public bool Frozen { get; set; } public bool InWater { get; set; } bool CanJump { get { return !Frozen && !InWater; } } } Bad. The Rabbit class can't know all the circumstances it can run into. Who knows what else will game designer want to add: may be an ability that changes gravity on an area? May be make a stack of bool values for CanJump property? No, because abilities can be deactivated not in that order in which they were activated. I need a way to seperate ability logic that prevent the Rabbit from jumping from the Rabbit itself. One possible solution for this is making special checking event: class Rabbit { class CheckJumpEventArgs : EventArgs { public bool Veto { get; set; } } public event EventHandler<CheckJumpEvent> OnCheckJump; void Jump() { var args = new CheckJumpEventArgs(); if (OnCheckJump != null) OnCheckJump(this, args); if (!args.Veto) return; ... } } But it's a lot of code! A real Rabbit class would have a lot of properties like this (health and speed attributes, etc). I'm thinking of borrowing something from MVVM pattern where you have all the properties and methods of an object implemented in a way where they can be easily extended from outside. Then I want to use it like this: class FreezeAbility { void ActivateAbility() { _rabbit.CanJump.Push(ReturnFalse); } void DeactivateAbility() { _rabbit.CanJump.Remove(ReturnFalse); } // should be implemented as instance member // so it can be "unsubscribed" bool ReturnFalse(bool previousValue) { return false; } } Is this approach good? What also should I consider? What are other suitable options and patterns? Any ready to use solutions? UPDATE The question is not about how to add different behaviors to an object dynamically but how its (or its behavior) implementation can be extended with external logic. I don't need to add a different behavior but I need a way to modify an exitsing one and I also need a possibiliity to undo changes.

  Read the article

• Design to distribute work when generating task oriented input for legacy dos application?

  - by TheDeeno

  I'm attempting to automate a really old dos application. I've decided the best way to do this is via input redirection. The legacy app (menu driven) has many tasks within tasks with branching logic. In order to easily understand and reuse the input for these tasks, I'd like to break them into bit size pieces. Since I'll need to start a fresh app on each run, repeating a context to consume a bit might be messy. I'd like to create an object model that: allows me to concentrate on the task at hand allows me to reuse common tasks from different start points prevents me from calling a task from the wrong start point To be more explicit, given I have the following task hierarchy: START A A1 A1a A1b A2 A2a B B1 B1a I'd like an object model that lets me generate an input file for task "A1b" buy using building blocks like: START -> do_A, do_A1, do_A1b but prevents me from: START -> do_A1 // because I'm assuming a different call chain from above This will help me write "do_A1b" because I can always assume the same starting context and will simplify writing "do_A1a" because it has THE SAME starting context. What patterns will help me out here? I'm using ruby at the moment so if dynamic language features can help, I'm game.

  Read the article

• How do I set the default selection for NSTreeController at startup?

  - by John Gallagher

  The Background I've built a source list (similar to iTunes et al.) in my Cocoa app. I've got an NSOutlineView, with Value column bound to arrangedObjects.name key path of an NSTreeController. The NSTreeController accesses JGSourceListNode entities in a Core Data store. I have three subclasses of JGSourceListNode - JGProjectNode, JGGroupNode and JGFolderNode. I have selectedIndexPaths on NSTreeController bound to an NSArray called selectedIndexPaths in my App Delegate. On startup, I search for group nodes and if they're not found in the core data store I create them: if ([allGroupNodes count] == 0) { JGGroupNode *rootTrainingNode = [JGGroupNode insertInManagedObjectContext:context]; [rootTrainingNode setNodeName:@"TRAIN"]; JGProjectNode *childUntrainedNode = [JGProjectNode insertInManagedObjectContext:context]; [childUntrainedNode setParent:rootTrainingNode]; [childUntrainedNode setNodeName:@"Untrained"]; JGGroupNode *rootBrowsingNode = [JGGroupNode insertInManagedObjectContext:context]; [rootBrowsingNode setNodeName:@"BROWSE"]; JGFolderNode *childFolder = [JGFolderNode insertInManagedObjectContext:context]; [childFolder setNodeName:@"Folder"]; [childFolder setParent:rootBrowsingNode]; [context save:nil]; } What I Want When I start the app, I want both top level groups to be expanded and "Untrained" to be highlighted as shown: The Problem I put the following code in the applicationDidFinishLaunching: method of the app delegate: [sourceListOutlineView expandItem:[sourceListOutlineView itemAtRow:0]]; [sourceListOutlineView expandItem:[sourceListOutlineView itemAtRow:2]]; NSIndexPath *rootIndexPath = [NSIndexPath indexPathWithIndex:0]; NSIndexPath *childIndexPath = [rootIndexPath indexPathByAddingIndex:0]; [self setSelectedIndexPaths:[NSArray arrayWithObject:childIndexPath]]; but the outline view seems to not have been prepared yet, so this code does nothing. Ideally, eventually I want to save the last selection the user had made and restore this on a restart. The Question I'm sure it's possible using some crazy KVO to observe when the NSTreeController or NSOutlineView gets populated then expand the items and change the selection, but that feels clumsy and too much like a work around. How would I do this elegantly?

  Read the article

• What do you need to implement to provide a Content Set for an NSArrayController?

  - by whuuh

  Heys, I am writing something in Xcode. I use Core Data for persistency and link the view and the model together with Cocoa Bindings; pretty much your ordinary Core Data application. I have an array controller (NSArrayController) in my Xib. This has its managedObjectContext bound to the AppDelegate, as is convention, and tracks an entity. So far so good. Now, the "Content Set" biding of this NSArrayController limits its content set (as you'd expect), by a keyPath from the selection in another NSArrayController (otherAc.selection.detailsOfMaster). This is the usual way to implement a Master-Detail relationship. I want to variably change the key path at runtime, using other controls. This way, I sould return a content set that includes several other content sets, which is all advanced and beyond Interface Builder. To achieve this, I think I should bind the Content Set to my AppDelegate instead. I have tried to do this, but don't know what methods to implement. If I just create the KVC methods (objectSet, setObjectSet), then I can provide a Content Set for the Array Controller in the contentSet method. However, I don't think I'm binding this properly, because it doesn't "refresh". I'm new to binding; what do I need to implement to properly update the Content Set when other things, like the selection in the master NSArrayController, changes?

  Read the article

• NotApplicable marker with display pattern

  - by Jeff Barger

  Ok, so I'm pretty new to Cocoa, especially Bindings, but here's what I'm trying to do. I've got a Core Data model consisting of two entities: Category and Item. Category has a to-many relationship to Item called children, and Item has a relationship to Category called parent. Item has two attributes that Category does not have: quantity and desiredQuantity. What I'd like to do is display the tree in an NSOutlineView with two columns. One column is bound to the name of either the Category or the Item. I want to the second column to display something along the lines of 2 of 5 for the Item rows and nothing at all for the Category rows. When I use a display pattern, the Category rows end up showing of I noticed that if I don't use a display pattern for the second column, and instead just bind its Value to either the quantity or the desiredQuantity, the Category rows show nothing; its only if I try to use the display pattern. How can I make it display nothing for the Category rows and still use the display pattern? Or can I? Edit: I guess I didn't explain what the NotApplicable marker has to do with anything - Category does have properties for quantity and desiredQuantity, but they just return NSNotApplicableMarker.

  Read the article

• Is it possible to have multiple tab-bar controllers in an app?

  - by Sheehan Alam

  I would like to design an app that has a RootView with 4 buttons. Clicking on each button will load another view that has its own tab-bar controller. The tab-bar controller for each of the views is different. If so, how do I go about implementing this?

  Read the article

• Why is good UI design so hard for some Developers?

  - by Chris Ballance

  Some of us just have a hard time with the softer aspects of UI design (myself especially). Are "back-end coders" doomed to only design business logic and data layers? Is there something we can do to retrain our brain to be more effective at designing pleasing and useful presentation layers? Colleagues have recommended a few books me including The Design of Sites, Don't make me think and Why Software sucks , but I am wondering what others have done to remove their deficiencies in this area?

  Read the article

< Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >