CODEWITHSUNDEEP
iphoneiosipaduiviewcontroller
Duck
Duck

Reputation: 36013

iPhone - a UIView that behaves like a UIViewController

I need to create a class that will present a UIVIew and has a some code to initialize it before it is ready to show. I need to know when the view is ready, I mean, I need something like viewDidLoad or viewWillAppear, but as it is a UIVIew it lacks these protocols.

I cannot implement it as a UIViewController as I don't want to present it modal. It is really a rectangular view that needs to show on a screen side.

How do I declare this class? If the class is a UIView based I don't have the methods I mentioned.

thanks

Upvotes: 0

Views: 273

Answers (5)

codecaffeine
codecaffeine

Reputation: 894

I need to create a class that will present a UIVIew and has a some code to initialize it before it is ready to show. I need to know when the view is ready, I mean, I need something like viewDidLoad or viewWillAppear, but as it is a UIVIew it lacks these protocols.

You might want to rethink how your view is being used. It sounds like you're trying to put too much controller-like logic into your view. That's why you're wanting your view to behave like a controller.

More specifically: What exactly are you trying to accomplish? If you're waiting for data to load before display the view, that might actually be something to put in the controller that is calling the view.

To illustrate my point, imagine you're putting some text in a UILabel that you read from disk. The reading from disk isn't really related to the view. The view only cares what text it displays, not how it received the text. Once it's read from disk, you can create a UILabel with that text that you read. This allows the UILabel to be more flexible.

That example might not be at all related to what you're doing, but I use it as an example of the difference between a view and a controller. Anything not related with the display and drawing of the view shouldn't belong there.

Upvotes: 1

Rene Berlin
Rene Berlin

Reputation: 1171

The scenario you described is no reason for not implementing a UIViewController. Assume you have a container view A and a subview B. Both have their own UIViewController AC and BC. Now on AC you add the View B managed by BC:

[self.view addSubview:BC.view];

Upvotes: 2

hotpaw2
hotpaw2

Reputation: 70743

Implement a drawRect in youR UIView, plus an initialization flag. Just before the view is to be displayed the drawRect will be called. If the initialization flag isn't yet set, do your initialization and set the flag. This will only look good if your initialization can be done quickly (no long synchronous calls).

Upvotes: 1

Amy Worrall
Amy Worrall

Reputation: 16337

You probably want to be using UIViewController.

You don't just have to present them modally. You can get your view controller's view with yourViewController.view, and add that as a subview of whatever view you want.

If you're targeting iOS 5, there are a few new methods (such as addChildViewController:) designed to make doing things like this easier. You can do it on iOS 4 too though, and it'll still work.

Upvotes: 1

dbgrman
dbgrman

Reputation: 5681

Any reason to not do that kind of stuff inside the initWithFrame method on a UIView? Also, you can do additional stuff on layoutSubviews. A view controller has viewDidLoad because the view is lazy loaded (from a nib or otherwise - it also has a loadView). It has viewWillAppear and viewWillDisappear because it is managing the view (btw, even the view controller is managed by another view controller - these methods are called when you have the controller within a UINavigationController or UITabBarController or such classes which mange UIViewControllers. - the view itself is not really managing anything. All it knows about is how to draw itself. For that, you have layoutSubViews, drawRect, etc.

Doing some heavy stuff upon view's load will definitely kill the UI performance. You probably need to implement another kind of design pattern that will asynchrounously assign data values to the instance of your custom view - when that is done, you call layoutSubviews or setNeedsDisplay to update the view.

Upvotes: 3

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