So I have a "main" View linked with my main .h/.m ViewController files.
In a process of the application, a second View is called that overlays part of my main View in a "popup" style.
I'm wondering if it's a good idea to use the original main ViewController .h/.m files for both the main View, and the second View? If not, I'm genuinely interested in why that is not to be considered a good idea. If this is in-fact a standard practice, what is the cleanest way to do so?
It's typically good practice for your view controller to "control" what comes on and off the displayed view its responsible for. If you are just presenting something very simple, it would be fine leaving it (the code) in your view controller - an example of this might be a background view with a different color.
If however, your view has many responsibilities, such as responding to touch events, you may want to create a subclass of UIView and put your code in that file. Then back in your original view controller, you would simply import that subclass and instantiate the view and present it (add subview) when needed.
Using a common pattern like delegation, your subclassed UIView would control it's own logic and perhaps via delegation, send messages back to the view controller when needed for items like dismiss, or save or any number of functions it might do. A common example of this is UITableView.
hope that helps
Related
For now I have a single login view controller that hide and adds subviews dynamically based on user interaction. Is it better to have multiple UIViews with one view controller, or multiple view controllers?
The benefit of having children UIViewControllers would be if you needed to care about the view lifecycle in any of the children. For instance, if in some of your subviews (child views) you needed to know if it appeared to trigger some logic, then it would be good to use children UIViewControllers.
Another reason might be, if you wanted to use view controller transitions within your custom container, as described by Apple in the UIViewController class reference:
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewController_Class/index.html#//apple_ref/occ/instm/UIViewController/transitionFromViewController:toViewController:duration:options:animations:completion:
But, to me it doesn't sound like you would need this, it sounds like you would just show/hide your views, or otherwise animate them.
But if your views don't care about any of that, and just need to render UI elements, I'd say using children UIViewControllers adds additional complexity without much benefit.
This is under the assumption that either way, all your views are living on the single UIViewController's view. If you are pushing and popping view controllers inside a UINavigationController, or presenting ViewControllers modally, you definitely should use UIViewControllers for that.
Also, you definitely shouldn't put all your view code inside that single view controller. You should use subclasses of UIView, or some other mechanism of making sure you separate your components.
For example you might have:
LoginViewController - organizes and hides and shows the individual views
SignInView - shows the sign in form
RegisterView - shows the register form
...etc
Of course its better to have multiple view controllers for many reasons:
Each view controller has its own code/logic/functionality.
Better for memory management. Once you're done from a view controller, system will automatically deallocates it from memory. Using multiple views will be overload in your system when some views are not used.
Better organisation for your project. You will just present/dismiss/push/pop view controllers and pass data between each other. Instead you will deal with horrible logic for hiding and showing UIViews.
Using one view controller will have a massive amount of code which in long term the project will be an impossible mission to manage.
Having multiple view controllers is better in the sense that you would have more ease at coding them individually. Also Navigation will be good which is good for User Experience.
Memory Management will be efficient.
The MVC architecture(Model View Controller) will instead become Massive View Controller which will be a headache while debugging.
Check out this answer for more clarity. I think you are confused between ViewController and View.
Check out the accepted answer of this question in the link. Hope it helps.
About viewController's "viewDidLoad" and "viewWillAppear" methods
I'm new to Swift, so I apologize for my lack of knowledge of almost anything related to Swift.
Right now, I'm developing an app that uses the ARSlidingPanel library, so now there are two ViewControllers present on the screen (Main view, with the dark background, and Panel view, which is the green background). I want to be able to set vars/call functions from the Panel view to the Main view. For example if I click a button in the panel view, I want to display some text in the main view. Right now I've started with using static vars but from my knowledge of Java/Android, I know this is probably not the right way to go. Any tips for a cleaner/more acceptable way of doing things?
There are a few different options here. However, the first thing that comes up to mind is if you really need to use two independent view controllers for the same view?.
One solution would be to use delegates. Write a swift protocol that has has the methods and functionality you want to expose, for example setting up values in the view controller's outlets, then implement the protocol in one view controller. In your other view controller, you can then create a delegate variable of type UIViewController -let delegate: UIViewController - and use that instance of your delegate to modify the view. Here's a guide on this
Even better, you can add view controllers as sub view controllers
of your view, apple provides a good bit of documentation on this, you
can find it
here.
Hope this helps.
There's a particular control which I'm trying to build properly. I refer to it as an ImageTile. It's basically a little square box, which, when the user taps it, will present the user (via an action sheet in a popover) the option of selecting an image from the library, or taking a photo. Depending on the response, I then either present the UIImagePickerController inside a popover (for selecting an image) or modally (for taking a new picture). Once they take/select the image, I have a modal view which appears and allows them to edit the picture in a few simple ways. When they finish editing, the modal dismisses, and the original ImageTile, rather than being a blank square box, gets filled up with the user's edited image.
The issue is that this ImageTile control is going to be used profusely throughout several different parts of the application, across numerous View Controller hierarchies, and so on... and I really want it to be a basically totally self-contained unit, such that whenever I stick an ImageTile inside a UIView onscreen, all the above functionality is handled by the ImageTile itself.
Initially, I made it a UIViewController subclass (so it could present modals etc), and just added its view as a subview of a "holder" view onscreen. I know this isn't recommended, as the controller isn't part of the VC hierarchy then... and also, I wound up with some really weird behavior regarding things like autorotation, especially when the camera was involved.
What's the "right" way to implement something like this?
I think what you've done by making it a UIViewController subclass is correct. You should just use the methods that UIViewController exposes for adding child view controllers, such as - addChildViewController:.
You will also note that Interface Builder has a Container View object designed specifically for holding a place in the hierarchy for a child View Controller:
I want to present view controllers as simple as with native presentViewController:animated:completion:, dismissViewControllerAnimated:completion: methods, but use custom animations for this.
The common way to do this is to perform custom animation (using view screenshots instead of view itself) and call presentViewController:vc animated:NO completion:… after.
But in this case view controller life-cycle messages are sent not in time. viewWillApper: and viewDidAppear: sent together instead of normal way: the first one just before animation and the last — after. Also they sent with animated parameter set to NO.
The other bad thing is that screenshot of a view (for animation) captured before viewWillApper: called. So it can be some outdated, and this will cause flicking at the end of animation.
I've searched lot of related projects on github/cocoapods (SO answers too), but did not find any with the right life-cycle of presented view controller. There are sometimes even worse solutions like simple views changing without any calls to life-cycle methods.
Possible solutions I know:
iOS7 — I can't, I need it in iOS6 too
Use transition between contained view controllers — Not as simple and reusable as "modal presenting"
Use tricky animations like here — my animation can't be implemented in similar way
While writing this question I thought about custom segue with overridden perform: method. But looks like it's not easy too. At least I don't know how to use it without storyboard and how to do dismiss in easy way.
Do you know how to present view controller with custom animation in iOS6 and make it's life-cycle happy?
Update: finally I've decided to use container view controller. It has ability to customize transitions of it's children and preserve VC's life-cycle. The bad side: it's not as easy as custom transitions in iOS7. It needs container, making xib some harder. And needs additional code to support.
Background
I'm using interface builder to create the UI for an app I'm working on. The app has a single screen that displays a series of buttons. Clicking on a button displays an associated view which overlays the buttons. Clicking another button hides the previous overlay view and displays another one.
Too make managing the UI easier in IB I've decided to create multiple nib files for each sub view that is to appear when clicking the relevant button. I'm then loading the sub view's nib file in the view controller's viewDidLoad method using the UINib class.
The idea behind this was to avoid having multiple views stacked on top of each other in a single nib file as this would be hard to manipulate in IB. I could have created all the views in code but this would require a lot of tedious coding as the layouts of each sub view are quite complex (with multiple child views).
Example code loading a sub view from a nib file.
- (void)viewDidLoad
{
UINib *aSubViewNib = [UINib nibWithNibName:#"aSubView" bundle:nil];
NSArray *bundleObjects = [aSubViewNib instantiateWithOwner:self options:nil];
// get root view from bundle array
UIView *aSubView = [bundleObjects objectAtIndex:0];
[self.view addSubview:aSubView];
...
The code above is repeated for the other views.
To summarise I have a single screen iPhone app that has layered views that are shown/hidden by clicking buttons. This is achieved with a single view controller with an associated nib file and a series of additional nib files for the sub views which are loaded in the view controller's viewDidLoad method.
Questions!
Sorry for the long introduction but I wanted to be very clear what it is I am doing.
Is my approach bad or unusual?
Are there any potential issues to doing it this way?
What have other people done when they need a dynamic interface and
still want to keep everything in Interface Builder?
Notes
Before anyone asks why don't I just display the sub views on a new screen and use the navigation bar, let me say that I have very good reasons and I do understand iOS UI guidelines. The above use case is not exactly my use case but it's one that clearly describes the problem without getting bogged down in my development app.
Also I know I could have written all the sub views as code but each sub view has a complex layout of child views and it would be a lot of code and messing around to try and get them looking right.
Thanks in advance.
There isn't necessarily a 1-to-1 relationship between view controllers and views. Most views contain many subviews, which are views themselves, so this literally doesn't make sense.
However, depending on the complexity of the views (including their content), you may want separate view controllers... or not.
For example, if you have two sbuviews that are each tableViews, you may want to have one view controller for each tableView. This is because each tableView is looking at the same delegate methods, and if they are in the same viewController, then the delegate methods have to differentiate between the tableViews. The delegate methods have signatures that allow this, but, in my experience, it can really make for a messy code design that is hard to follow and hard to manage.
On the other hand, you may have two tables that are managed by the same viewController, where one table is filled with meaningful data and the other is simply a place holder (as when the data source is empty). One might be visible while the other is not. Why make you life complicated by creating two view controllers when both are driven by the same data source (the model)?
In my mind, it comes down to how difficult it is to follow and manage the code. If the complexity of using a single view controller becomes burdensome, consider using more view controllers.
UPDATE
By the way, I have an example that I am currently working with that may illustrate a similar situation. In the InAppSettingsKit, that a lot of developers use, there are several xib files for pieces of the main view. You can look at the structure here on github. There is one main view controllers and several xib files. (There is also what I would call a "helper" view controller and an email composer view controller.) In this example, the xib files may be used multiple times to specify the layout of table view cells. There is no view controller for each xib file, though. (The documentation for InAppSettingsKit is sparse, so these things may not be obvious just by taking a quick look at it.)
Every View should have a corresponding UIViewController. Using one ViewController to "Control" more than one view breaks the MVC paradigm. "Controlling" multiple "views" from one controller will make it much harder to change one thing without breaking something else. The choices you make on how to present the content to the end user will be different for every individual. So if you say a NavigationController won't work in your case, maybe a Modal view is the answer or, you might just instantiate your custom UIViewControllers and add them to your view ([addSubview:]), if thats the road you want, but like I said, it would be beneficial for you to make a "controller" for each view object along with the corresponding xib. If you need information sent back, use a delegate or use Notifications to send the message back to the parent view. I learned the hard way that not following MVC paradigm, will make you life miserable. Try and keep your code as decoupled as possible. And read up on the MVC design pattern, you won't regret it.
actually its possible to do this.
Open your .xib file,select File’s Owner(in placeholder) -> "identity inspector" (utilities) -> change class name to your controller classname -> press control and drag file's owner placeholder to View object, select "view" in dialog.
Now you can customize your view.
p.s. you can use the same outlets as first xib, you need only to drag them to the new xib(+control sure).
here is an explained tutorial:
http://irawd.wordpress.com/2013/09/05/how-to-link-a-xib-file-to-a-class-and-use-2-xib-files-for-iphone4-and-iphone5/