Could anyone help me first when I can use AOP, and what is it exactly in an iphone programming.
I need to access to the app project source code and call some of the functions and be notified their views loaded from outside like a library.
I found these so far, but looks very complicated to follow. Some doesnt build or the source code removed.
https://github.com/ndcube/AOP-for-Objective-C
https://github.com/moszi/AOP-in-Objective-C
ACAspect on cocoadev
If you have a specific view in a view controller and want to be notified when it is loaded, you can register for a KVO notification when that instance variable (the outlet) changes.
You'll want to read up on Key Value Observing in Cocoa. There are several methods you will need to learn how to use.
Do a search on "Introduction to Key-Value Observing Programming Guide" in the XCode docs and read that section.
Make sure you balance each call to addObserver:forKeyPath:options:context: with a call to removeObserver:forKeyPath:, or your app may crash after the observing object is deallocated.
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I am writing an iOS app that registers for call events (not-in-call, dialing, disconnected etc).
I have code that registers for the call event, but I'm not sure where is the correct location to put it (in the Model? In the Controller?).
All samples place the code in the app delegate, but that seems awkward. After all, the app delegate is not part of MVC.
Thanks!
After all, the app delegate is not part of MVC.
I could argue, but I have a feeling you worry too much about the "correct design". If you want to change the place of these event handlers, I'd put them somewhere in the controller (certainly not model, because they are not data providers...)
But after all, why are they "awkward" in the app delegate? That's exactly why the singleton application object has a delegate: system-wide events shall notify the app (and its delegate), respectively, and not some internal part of the application. That's mixing things up.
Since these events control parts of your application the best answer would be: in a controller.
This Apple style to put lots of stuff in the delegate is indeed bad coding practice.
I'm new to iphone development. There's a lot of books on this topic available. But most of the beginner's guides are mostly concerned with Interface Builder usage and lack the information about existing built in XCode code templates or something that could help me in understanding MVC implementation in code. I found that it is possible to write working iOS program without ViewController at all. Well, it seems to me like that after working with the sample code called ViewTransitions.
So, the question is - why is that possible to avoid ViewController implementation in a program that has an interface with a button? If the answer is going to be too long, could you please recommend kind of tutorial or manual covering this topic.
Thanks in advance.
#user697562's answer is essentially correct: in the case of ViewTransitions, the role of the controller is played by the app delegate. The app does next to nothing -- it just switches betweeen two views to demonstrate several possible transition effects -- so a UIViewController isn't really needed there.
Notice that there's also nothing in ViewTransitions that you could really call a model object. If you're looking for a strong example of MVC, ViewTransitions isn't the best project to look at. Other sample projects, such as TheElements, give a better demonstration of MVC in action.
There is a concept called delegation. A concept which helps maintain MVC. It helps to keep the model separate from controllers. For eg: - UITableView/UICollectionView , which knows how to display the data and other ui stuff.
But it does not know which cell to display or what data to display at a particular index. And this is where delegation and the delegate object comes into place. UICollectionView handles all the view part whereas all the non view part is handled by the delgate object, which gives the required data for the view. This way a delegate(usually a separate view controller) acts as a data source and UICollectionView as a ui renderer.
in ViewTransitions, there IS an App Delegate, which is kind of your sole "controller". Even ViewTransitions has:
transition.delegate = self;
IOS is a bit different from some frameworks in that you aren't as "in control" of what is going on. It often uses a delegation model where you set your code as the delegate, but it (IOS) is in control. Still, you can write in MVC style, it's just your "C" isn't fully in charge.
This is Cocoa Touch (et al), iPhone, XCode only.
After completing my first commercial iPhone app, I'm struggling a bit to find a way to start and expand an app from scratch which gives the most linear development (i.e., the least scrapping, re-write or re-organization of code, classes and resources) as app specs change and I learn more (mostly about what Cocoa Touch and other classes and components are designed to be capable of and the limitation of their customization).
So. File, New Project. Blank window based app? Create the controllers I need, with .xib if necessary, so I can localize them and do changes requested by the customer in IB? And then always subclass each class except those extremely unlikely to be customized? (I mean framework classes such as UIButton, CLLocation etc here.)
The question is a generic 'approach' type question, so I'll be happy to listen to handy dev practices you've found paid off. Do you have any tips for which 're-usable components' you've found have become very useful in subsequent projects?
Clients often describe programs in terms of 'first, this screen appears, and then you can click this button and on the new screen you can select... (and so on)' terms. Are there any good guides to go from there to vital early-stage app construction choices, i.e. 'functions-features-visuals description to open-ended-app-architecture'?
For example, in my app I went from NavBar, to Toolbar with items, to Toolbar with two custom subviews in order to accommodate the functions-features-visuals description. Maybe you have also done such a thing and have some advice to offer?
I'm also looking for open-ended approaches to sharing large ("loaded data") objects, or even simple booleans, between controllers and invoking methods in another controller, specifically starting processes such as animation and loading (example: trigger a load from a URL in the second tab viewcontroller after making sure an animation has been started in the first tab viewcontroller), as these two features apply to the app architecture building approach you advocate.
Any handy pointers appreciated. Thanks guys.
Closing this up as there's no single correct answer and was more suitable for the other forum, had I known it existed when I asked :)
If you want to know the method I ended up with, it's basically this:
Window-based blank app
Navigation Controller controls all, whether I need to or not (hide when not used)
Tab Bar Controller if necessary
Connect everything <-- unhelpful, I know.
Set up and check autorotation, it might get added to some view later.
Add one viewcontroller with xib for each view, you never know when they want an extra button somewhere. It's easier to copy code than make the max ultra superdynamic adjustable tableviewcontroller that does all list-navigation, etc.
Re-use a viewcontroller only when just the content differs in it, such as a detail viewcontroller.
Minimize code in each viewcontroller by writing functions and methods and shove them in a shared .m
Everything that's shared ends up in the App delegate, except subclassed stuff.
Modal viewcontrollers are always dynamically created and never have an xib.
There are tons of resources concerning coding on the iPhone. Most of them concern "how do I do X", e.g. "setup a navigation controller", or "download text from a URL". All good and fine.
What I'm more interested in now are the questions that follow the simpler stuff - how to best structure your complex UI, or your app, or the common problems that arise. To illustrate: a book like "Beginning iPhone 3 Development" tells you how to set up a multi viewcontroller app with an top 'switcher' viewcontroller that switches between views owned by other view controllers. Fine, but you're only told how to do that, and nothing about the problems that can follow: for example, if I use their paradigm to switch to a UINavigationViewController, the Navigation bar ends up too low on the screen, because UINavigationViewController expects to be the topmost UIViewController (apparently). Also, delegate methods (e.g. relating to orientation changes) go to the top switcher view controller, not the actual controller responsible for the current view. I have fixes for these things but they feel like hacks which makes me unhappy and makes me feel like I'm missing something.
One productive thing might be to look at some open source iPhone projects (see this question). But aside from that?
Update
To clarify: I suppose what I'm asking about could be summarised as "Recipes and Gotchas for iPhone development". The sort of things that are of interest to developers, but aren't covered in any of the iPhone books etc. that I've seen, such as:
I'm writing an iPad app and want a UISplitViewController presented to the user only some of the time, which Apple seem to be saying I can't do. Is it possible? How?
Apple don't give me a way to stylise my app in a convenient, across the board way (e.g. font tweaks, or colours). How can I approach styling my app?
Memory management isn't made any easier by some of the inconsistencies in UIViewController method names (e.g. viewDidUnload is not the opposite of viewDidLoad, despite the name). Is there a consistent easy way to tidy that up and make view controller memory management less error prone?
How can I consistently and easily test my view controllers for behaving correctly when a memory warning comes in? It's easy to simulate a memory warning in the Simulator, but if the UI I want to test is showing (and is a 'leaf level' view controller), it won't get its view unloaded because it is currently visible.
N.B. I'm not actually asking the above questions here -- I think I have decent answers to them! -- just giving examples of 'good' questions that illustrate this stackoverflow question.
The WWDC talks available on iTunes U (at http://developer.apple.com/videos/wwdc/2010/) have some great information about structuring, especially in the Application Frameworks section.
If you're talking about code, use the Model/View/Controller pattern like in most Web applications:
The model code defines the objects that your program represents. A time tracker app, for example, might have model objects like Task, TimeSlice, and User (especially in a network setting).
The view code is provided for "free" with the iOS SDK, unless you need specialised view code. These are UIImageView, UIButton, etc.
The controller code bridges the 'gap' between the model and view. The controller will change the views to reflect the model selected by the user and facilitate the selection of model objects.
This is the base design pattern for any iPhone app, and it's the one that most will use.
If, on the other hand, you refer to what we in my company call UX (user experience) design, however, you can't beat the Apple HIG guidelines in the Apple iOS SDK documentation set, available online or in Xcode from the Help menu.
The other thing I recommend quite highly is to play around with some test/dummy code. Nothing can top experience. Experimenting with the iOS SDK and getting your hands dirty will allow you to truly learn the best ways to design apps.
Edit:
Also, delegate methods (e.g. relating to orientation changes) go to the top switcher view controller, not the actual controller responsible for the current view.
Can you clarify? In all of the apps I've written, the currently shown view controller receives the orientation change methods. Note that there are two methods. shouldAutorotateToInterfaceOrientation: allows you to decide if the view should rotate, and didRotateFromInterfaceOrientation: allows you to re-layout the view if necessary.
Please go through this link. In this they have explained clearly about design patterns.
http://www.raywenderlich.com/46988/ios-design-patterns
You might want to consider watching videos like the CS193p course from Stanford on iTunes U. They go through the most important parts of iOS development in deep, and give some source code.
As far as I can tell, there isn't a book or resource which deals with the sort of advanced gotchas and recipes that I was looking for. Loads of useful resources exist, but just not addressing the stuff I'm thinking about.
Been researching how to send data from one child view to another child view. The application has several views, where one is kind of real-time Settings view. Changes in settings should effect stuff inside other views.
NSUserDefaults seems to be popular, but I don't want persistent data nor automatic saving into database/file. Looks like potential slowdown, which I want to avoid.
Second popular thing is passing a reference to some common top level object into each child view. Just haven't found any tutorial, which would show me in detail how to do this... Most likely so easy, no tutorial is needed - after you figure it out once! Would appreciate, if you can point me to right direction (URL)!
Question: I'm thinking about using one "singleton object" to store "global data", access it from everywhere anytime. What could wrong with this? If I create it at e.g. appDelegate.m it should exist before anyone tries to access it, right?
I'm looking at this sample code.
I would recommend using delegates and/or notifications.
Instead of creating a new singleton in the app delegate, add the necessary data (or, even better, references to the data) in the app delegate and have the views have references to the app delegate.
You can also set up notifications so that your views can keep track of changes to the data that they display.
The beauty of a singleton is that it is automatically created when you first access it via some [singletonClass sharedInstance]. So you don't need to "create" it while launching. If it is global data that needs to be accessed from any view singleton might be the right way of doing this.