I am building an app with many views and subviews.
I am trying to figure out how to approach creation of the subclass.
one simple example:
I have a table view with heads view and footer view. (I have much more complex views then this one, but I am trying to explain my point with a simple one).
In the beginning I didn't want to create views subclasses for every view, but I found that my code is getting complex and hard to navigate in.
Then I found my self creating a view for every subview in the main view. The truth is that I like it better cause my code is clearer to me. Th only thing is that I don't know what are to cons and pros of each approach.
How do you decide when to create a custom view or create it's code in the main view?
Thanks
I usually create a UIView subclass only when there is specific functionality that would be best done in such a class. This might be that the view is a control such as a keyboard to enter a value or a UITableViewCell subclass.
Otherwise I would generally not subclass UIView but just create the view hierarchy in Interface Builder or in code and then use the UIViewController subclass to do all the business logic.
Basically, in general with iOS programming, you want to have all the logic of how a "view" (or screen, or whatever you want to call it) in a UIViewController subclass. It's hard though to really give good advice without fully understanding your hierarchy.
Related
Is it a good practise to creates views in xcode and hide them and when required show them?
I am asking that because I prefer to create views visually and not in code.
If the view is to complex(a lot of subviews) should I create a new view controller to it?
I know there isn't a specify question here but I really need a clarification on this matter.
Regards
One of my first iOS applications had a tab bar and views that the user could switch between. Originally it was done by hiding and showing the right views depending on what the user pressed on the tab bar. This ended up being a complex disaster.
I then rewrote the app so that each tab bar view had its own UIViewController with its own set of views. That turned out to be so much easier to manage. (I also changed from using Interface Builder to straight code for creating the views, but that's beside the point and you can continue to use IB if you want.)
As for me, I prefer folowing practice:
Usually, a use storyboards,where views are placed, but if a view is complex, I create a separate XIB file, arrange all subviews there, and then in storyboard drag an UIView subclass and connect my XIB view with it.It helps to avoid mess in storyboard.
As for hiding views, I also don't recommend such practice as it can become very complex to understand your code and all those views are allocated when XIB is loaded, so the mobile developing rule "do as lazy as u can" is not met. We should try to spend as less memory as it's possible.
UIView is the best way to create iOS app, esp. if you want to reuse the code.
For example if you have same view to present in iPad n iPhone then using UIView can result in lots of similar code in View-controller
In another case if your view might need to have multiple table view it can be quite complex to handle each with delegates in ViewController. But separate view will solve this problem.
I have made my 1st open source code after learning how to use View
https://github.com/bishalg/BGRadioList
which I had learned from
http://www.raywenderlich.com/1768/uiview-tutorial-for-ios-how-to-make-a-custom-uiview-in-ios-5-a-5-star-rating-view
About the hiding view - I have used lots of hide and show view codes in my apps but believe me at one point it will become complex and unmanageable if you have lots of views.
I have a view that contains a mapview and a tableview, similar to how to the facebook nearby places screen looks in the facebook app looks.
I put the screen together using interface builder. I have outlets to the tableview and map. And, I set the UIViewController that controls the main view to be the delegate for both the mapview and table view. Everything works perfectly.
However, this main UIViewController is now pretty messy because it has to respond to methods on behalf of it's own view, the mkmapview and the uitableview. However, data is somewhat shared between the map and the table view.
I am wondering if this is where UIViewController containment comes in? Or, if I should should just make custom objects to act as delegates for those two views. I am looking for the correct design pattern to use in modern iOS. A few years ago just mashing it all into the same controller would be the way to go. Maybe it still is the way to go.
Both your ideas are good thoughts, but...
Controller containment is typically used for more navigation related purposes, like a UINavigationController.
Custom objects that do some of the delegate/datasource work, that's a good thought too, but a little clumsy to the extent that they share data with the view controller and each other. This might be a good solution especially if other view controllers will need the same delegate/datasource behavior.
A third alternative, and probably the best of the three, is to create class extensions of the view controller (see apple doc here). These can be thought of as parts of your class in different files.
I'm having a uiscrollview with 3 slots, each holding a tableview with different data.
As you can imagine, handling 3 tableviews on the same viewcontroller is a bit of a mess.
So I was thinking about using multiple uiviewcontrollers to handle the different logic required for each tableview. However I can't seem to do this since uiviewcontrollers load in a modal way/blocking the entire previous view: this leaves me unable to continue to use the uiscrollview placed on my root view controller.
Is there a way to solve this? Or pack UIView logic and behavior in some sort of stub/hidden uiviewcontroller that doesn't block the view below?
You are looking at this the wrong way. Separating your tableviews is a good idea, but there is no need to use a view controller.
Let's say you have three tableViews: tableViewOne, tableViewTwo, and tabelViewThree.
The problem (as I understand it) is that all of your logic code (datasource and delegate methods) are getting all mixed up. So, just create a subclass of NSObject for each tableView and use that object for the datasource/delegate. Just make sure you set the datasource/delegate properties of the tableView to the right object.
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/
I have a design question. I have a scroll view that I want to use as a means of navigation. I.e. the user can slide between screens. At present, I am creating view controllers and putting their views directly on the scroll view:
aViewController.view.frame=CGRectMake(0,0,320,200);
[self.myScrollView addSubview:[aViewController view]]
Etc, for all 3 view controllers.
I know this isn't best practice. But I can't think of any other way of doing it. Ideally I would like to get the same behaviour as a navigation controller except the fact that I'll be using a scroll view. Any help would be greatly appreciated.
You have to be aware that this breaks certain UIViewController behaviors because these child view controllers do not get informed about interface rotation events and their viewWill/Did(Dis)Appear: methods will not work.
The alternative (until iOS 4.x at least) is to not use UIViewController subclasses for these subviews. You could easily create your own custom controller class (derived from NSObject) to manage a child view.
It's debatable whether that approach makes it easier overall, though.
I'm guessing what you're trying to achieve is something similar to this app?
http://itunes.apple.com/us/app/fanhattan-for-ipad/id436928538?mt=8
This app works in the same manner, using a scroll view for navigation. You can analyze that app, you'd get some ideas from it, i'm sure.