I have a lot of common logic, therefore all my viewControllers inherit from BaseViewController, BaseDetailsViewController or BaseWebViewController. The last two inherit from BaseViewController which inherits from UIViewController. The problem is I cannot use tableViews with static cells because my BaseDetailsViewController is not inheriting from UITableViewController.
I'v never used and inherited UITableViewController because the same could be achieved by inheriting from UIViewController, wiring it with an added UITableView and having implemented datasource and delegate methods. Therefore for the form type screens (SignUp or other data input screens), I use my own BaseDetailsViewController which adds nice and handy methods (input validation, custom styling, scrolling keyboard, handles input field navigation and etc.)
Using UITableViewController has two real benefits: 1) keyboard scrolling (if you use text fields) and 2) easy creation of your form UI elements inside on screen. The first benefit is irrelevant for me, because I'v already have my own implementation of this stuff inside BaseDetailsViewController. Regarding the second benefit, I'm creating my form inside scrollView which gives a lot of flexibility but it's a little bit more effort (especially when need to update the screen). Therefore I heard some guys implemented their own UITableViewController and then made it to inherit from their BaseViewController. Therefore I started to dig into this approach.
So far I'v came upon these two approaches:
Recreate your own tableVC. Not clear how to make it work for static cells. Currently my demo app crashes if my ReplaceTableViewController is not implementing numberOfRows and cellForRow, and not shows static cells if I implement them with dummy content.
method-swizzling. Not clear how to change class inheritance by injecting baseViewController inheritance for UITableViewController, thought still not clear which methods are needed to be added.
Anybody tried and want to share?
UPDATE I'm not using storyboards as I promote clean MVC - every screen as component should have its own Model, View (Xib), and controller, all stored in separate files to eliminate merge conflicts of multiple devs in large app projects (30+ screens). And therefore container view with embedded segue to tableViewController is also not an option.
UPDATE2 In case anybody would like to take a look why and how I'm doing this, here's a link to my open source template based new project generator framework which I started to publish recently.
Static cells need a UITableViewController. You can't changed this right now.
But to use static cells in a UITableView outside of a UITableViewController you can use a ContainerView in your Non-Table-UIViewController, where you place a real, separate created UITableViewController working with those static cells.
To share common code between multiple view controllers, inheritance is not that best solution as you found out by yourself while subclassing UIViewController vs. UITableViewController. You can use some sort of composition for sharing code or - especially for objective-c - categories.
Categories are not allowed to have its own properties, but there are workarounds possible with objc_setAssociatedObject.
Another approach would be to not use static cells, but dynamic cells in a UITableView with DataSource-Delegate :)
As you see in my screenshot, to reuse a special TableView with static cells, i place it in other ViewControllers in a ContainerView. Since you are not using storyboards, i am pretty sure that this can also be done by code without storyboard.
Related
I'm building an app that presents table views in a majority of the screens. They present a handful of different table view cells, but there is one that is presented in 3/5 of the table views. This cell, which displays a video and provides an interface for users to interact with the video (like, comment, flag, delete, play/pause, etc), has a fairly large delegate with seven methods/functions.
My question is:
Would it be a best practice to set up a separate controller that would be a property of my view controller to be assigned as the delegate to the cell, or to subclass a UITableViewController with the methods already implemented?
The problems I see with the latter is that I would then have to implement a weird way to handle the data source (set up methods to return the models, always ensure that videos are stored in that array) and the former just seems a little odd to the standard MVC practice. Any advice?
Update
I began factoring out a data source to use that implements the cell's protocol. Another issue that I seem to be running into is displaying multiple cells, i.e.:
I have a searchDisplayController that displays UserCell's and VideoCell's, based on the selectedScopeIndex of the search bar. One way I could handle this is to create a dataSource for this tableView that handles both cases, or swap out data sources based on changes to the selectedScopeIndex. Are either of the two options looked down upon? Is swapping a table view's data source valid?
I solved this issue by implementing a UITableViewDataSource controller that would also handle the cell's delegates. I was able to shorten the 7 method delegate to a 3 method delegate on the data source, used to push new controllers, remove objects from the data model, and handle fading/updates.
Granted, I needed to pass reference to the UITableView, the UIView, and the UIStoryboard of the source UIViewController, but the code is much more readable and manageable.
I am gonna design a component in IOS, in which we will have Table view and Grid View; means user can see his data in table or grid. So what i am doing is i added a UIViewController and added two child view controller one for table and another one for collection view. I am handling everything using UIViewController only. Its means when user wants to use my component he has to add as a child view controller only. My question is that "Is it the best practice to use UIViewController like i am doing or Should I convert everything to UIView because UIView is light weight." I am gonna write only presentation logic in my component. We will get data from outside using delegate. And if i should use UIView then when should i use UIViewController?
Thanks
Your current approach is correct.
UIViews should do one and only one thing: paint a view when asked to.
UIViewControllers are more complex. They are are responsible for setting up views with any data they need to do their job, compositing multiple views (or view controllers) together if needed, responding to events from view components or from the device in general, and communicating with the rest of the code/system.
Because your code wants to show two different kinds of information, it fits the UIViewController much better than the plain UIView style.
As you've pointed out, Apple themselves have many examples of UIView subclasses that have delegates and do complex things. However, if you're writing a new component and it is complex (as yours is), I seriously recommend going for the UIViewController approach.
A note on history: Apple used to be of the advice that UIViewControllers should only show/composit UIViews and not other UIViewControllers (even though, confusingly, they didn't always follow their own advice!). This would align with their making of some quite complex UIView subclasses. However, they changed this stance a while back, and added support to UIViewControllers for compositing other UIViewControllers' views inside them. If Apple's stance had always been as it is now, you might find that some of their UIView subclasses were implemented as UIViewControllers!
As an experiment, it would probably be quite educational to try and implement your component both ways. I predict that you'd find UIView approach more unwieldy, with you having manually re-plumb some of the 'wiring' that you'd get 'for free' with the UIViewController approach.
Avoid putting logic in UIView subclass.
As I think you can make grid view by using table view just simply add multiple views on each cells
at time of switching grid to list or list to grid simply check your type and reload tableview
I am writing a text editing app. I target iOS 6 and 7, and use storyboards and autolayout.
I thought this layout for the welcome screen would work well:
<Files in a table view>
<Instructions to user>
<Settings>
The settings view is pretty complex, and will probably benefit from having its own view controller. The instructions view is static, and has no logic.
I can think of three ways to organize this:
Create this as a table with three sections, where the 1st section is the list of files, and the 2nd and 3rd section are big, custom cells with.
Wrap all three views in a scrollview
Wrap the instructions and settings in a scrollview
I prefer the first solution, as it seems to be the, most natural way for the user to navigate, but I haven't seen any examples of adding a viewcontroller as a cell for a tableview anywhere, and haven't been able to google me any. Prototype cells do not seem like the right way to go for the settings view/controller either.
Best practice, suggestions, input?
Apple recommends only one view controller per "screen," so that rules out option 1. I wouldn't want to even start to attempt to embed a viewcontroller in a table cell and that just smells very wrong in any case.
You have three independent views that you want to scroll, and that clearly calls for a UIScrollView. As for the best way to organize this, I recommend creating modular UIView subclasses: one for the table, one for the instructions, one for the settings. See my answer on this question as to how you can package up views as reusable (not important in your case) and modular widgets: UIView and initWithFrame and a NIB file. How can i get the NIB file loaded?. Then you can create delegate interfaces for each one, and set your main view controller to implement them in order to communicate with each of the three "widgets."
Maybe this is a silly question, but I've bumped into it a number of times during iOS Development.
Sometimes I'll develop a view component that I want to use on multiple screens, so I'll decide to subclass UIView and make it something I can use in multiple places.
Then, I start adding functionality to it. Maybe it needs to respond to an NSNotification, or it is supposed to respond to user touches.
At a certain point, I start wondering if I should really be making a UIViewController subclass, and add it to my UI as a child ViewController.
Is there any consensus on where to draw the line between adding some behaviors to a UIView, and when to create a full UIViewController?
I can't tell you about the consensus, but here's my opinion:
Subclass UIView only when...
You want to do custom drawing
You need to customize some behaviour of an already existing UIView subclass
You have special needs for layouting subviews. Most layouting can be done by UIViewController, though.
Maybe for special touch handling that you can't be done with gesture recognizers
Subclass UIViewController in all other cases. You almost always need a controller anyway, for writing glue code that ties together views and models, or for handling user interaction. Consequently, Apple has made it easy in UIKit to let controllers do all the work and to keep views as "stupid" as possible. For instance, it is very simple to nest controllers to create complex view hierarchies, without the need to have a single view subclass.
An indicator that subclassing UIView is not the first thing one should do is the section titled "Alternatives to Subclassing" in the UIView class reference. An indicator that subclassing UIViewController is the preferred thing to do is that there is no such section in the UIViewController class reference :-)
You should use a controller anytime that you need to handle or control data. Views are supposed to be as stupid as possible, not knowing what they are displaying but rather where. You can easily subclass and reuse ViewControllers. A good example, say you need to retrieve a string (or text) from the user throughout your app via a popover controller and a modal. Create a generic subclass of UIViewController that has a view with a textfield and a button. You can then use this view and it's controller in any capacity you need. Reusing it in the popover, modal or anywhere else (and generally passing the data back through delegation). Since you are dealing with data you should not being using a sole subclass of UIView.
From my experience I subclass UIViewControllers more often then UIViews. It is a little difficult for me to understand if you are solely talking about Containers or reuse of views in general application workflow. Either way though it should be the same.
I've used the embedded view controllers to load reusable table views from time to time. I've found that it's useful sometimes but not always. Communication between the two can be cumbersome, like if you want the embedded controller to communicate back up to the container. Delegation makes it easier but still cumbersome. It also limits you to iOS 6, if I remember right iOS 5 and lower don't support embedded controllers.
If it's just adding methods you can use a category to store some extra methods. I do that a lot on NSManagedObjects that I don't want to subclass and if I regenerate the NSManagedObject from the datamodel I don't lose the code in my categories. Gives me added functionality like calculated fields or conversion methods without having to subclass. If you don't need those methods for a particular instance just exclude the reference to the category.
Subclassing never is bad though IMO.
Often, when I'm making my apps, I'm in this situation : I have a UINavigationController, handling the view stack, some UIViewControllers, controlling their respective views...
But when I want to add several custom UIViews in my mainView, I don't know how to manage my code.
Each UIViewController needs to handle one and only one view (wich normally occupy all the screen size), and a view should not control their content (update it a the extrême limit).
You can't neither do this :
[myViewController1.view addSubview:childViewController.view];
So if I want to achieve something like this, what should I do ?
The orange parts have to be 3 instances of the same UIView(Controller?), but with a content depending of a NSObject (User, obviously).
I think this very important to segment your content, this should be an easy problem, but I found a lot of contradictory answers so, what's the best practice to handle this common issue?
Theses orange views should be instances of UIViewControllers in order for it to handle their UITableViewDatasource? Is addChildViewController relevant in this case?
I already found a lot of things which work, but I don't know what should I do...
Also, I'm using xibs.
Thanks in advance if you can help me (and other people I think).
You can do it either way (view or view controller) depending on how you want to handle things. Certainly, you can have one object be the data source for multiple tables, so in that case, you would just add multiple views. If, however, you want to keep your code more compartmentalized, then add view controllers, and have each control its own view -- to do this, you do need to use addChildViewController, and use the methods that Apple describes for creating custom container controllers. Alternatively, you can use container views in a storyboard which makes the process of creating custom container controllers simpler.
You're on the right path... Create separate instances of your subviews, and add them to your view. If you will have more than 3 (for instance, imagine coverview for your music, and you could scroll indefinitely left and right), I'd take a look at UICollectionViewController ... That will help manage cell re-use.
But, if it's just 3, just create three instances with different frames and add them to your view.
Here's how I'd do it:
each orange box will be a custom view (inherits from UIView)
the view will have the label, image and the tableview.
since you are not sure of the number of instances of these views you'd be using, its better to use some kind of tagging, so that you can have one place for the datasource and delegate methods of the tables in these orange views.
in the datasource and the delegate methods, you can make use of the tableView.tag (same as the orangeView.tag property).
I personally dislike having more than one viewController in a view (except the splitVC), probably because I haven't had a such requirement.
I dont see how a uiviewcontroller for orange box would help, over a uiview.
as #James Boutcher mentioned in his answer, UICollectionViews will simplify this issue further.
Why not creating a UIView class and overriding the drawRect method and then adding subView for this class in your myViewController1.view