Hy everybody
I am a newbie ios programmer and I'm facing many doubts when I must switch the pages of my app.
With the term "page" I mean a UIView that fills the whole screen with some widgets (buttons, textboxes. tables..)
As far as I have understood what I've read I should use an UIViewController to manage each of these pages
since each page should be a screen’s worth of content.
My App starts with a ViewScroller with many buttons and when the user clicks one of these it opens a new page.
The first page is the UIView connected to the RootController Of the Window.
So far to open the new pages I add a child controller to the RootController and it's view as a child of the view of the RootController:
RicLocaliController = [[RicercaLocaliViewController alloc] initWithNibName:#"RicercaLocaliViewController" bundle:nil];
[self addChildViewController:RicLocaliController];
[RicLocaliController didMoveToParentViewController:self];
[self.view addSubview:RicLocaliController.view];
RicLocaliController.view.frame = self.view.bounds;
When the user clicks the "Back" Button I remove the child controller and the child view.
Going down this road I would get a dynamic tree of Controllers with their Views.
So far I have not encountered problems and my app can go up to a third level in the tree and come back. Each page behaves correctly when orientation changes.
But I'm afraid that adding, for each subpage, a child controller and a child view could be not the right thing to do.
I'm afraid that if I nest a lot of pages when the orientation changes the app could respond slowly since also the superviews will do something to manage this event.
So what I wonder is if what I am doing is completely senseless, if I should use Navigation controllers or some other way to manage my page changes.
Unfortunately my boss is not giving me enough time to study well the subject and so I would like an advice to follow the best solution possibly using the most standard and less complex component offered by the framework instead of the newest features.
I read a lot of web pages on the subject but it seems to me that there are many ways to manage the navigation beetwen pages and this makes me confused.
I apologize for my bad english but i'm tired and English it's not my first language.
You HAVE to do some studying. You will spend more time clearing up all your problems later otherwise... but, here are some tips.
Using nested ViewControllers leads to all kinds of trouble so if you are short of time, skip that.
Think of each "Page" as one ViewController. A ViewController has a property called View but that is actually just the top view of a whole hierarchy of views. A view is the base class for any visual object, like labels, buttons etc. All views can have subviews, so you can add an image under a label etc. and do really wierd stuff if you want to. I am just saying this to free your mind about how you can use views.
Now, ViewControllers are supposed to hold to code to ONE view hierarchy. That view hierarchy is for that View Controller only.
When the user wants to navigate to another page, you have a few alternatives:
NavigationViewController - that should be used when the user wants to delve down into data, like opening a detailed view of an item in a list etc. The NavigationViewController gives you help with back buttons, proper animation etc. You "pop" a viewcontroller to go back one level. If the user click the back-button, this is automatic.
TabBarViewController - use that if you want a tab bar at the bottom of the screen. Each tab is connected to a ViewController, that has it's own view hierarchy.
PushModal - If you are in a ViewController and just needs to get some data from the user, which is not part of the normal navigation of the app, you can push a new ViewController modally. This is the way you interact with iOS built in ViewControllers. This is also a good way to get a value back from the view controller.
There you have it. Go learn more. :)
It sounds like, for what you are using, you should be using a navigation controller. This will automatically handle pushing views onto the stack and then popping them off again later. This will also automatically create a back button (it is customizable) in the navigation bar.
If you are using iOS 5 or 6, I highly recommend trying out "storyboards" in Interface Builder. Storyboards allow you to graphically represent transitions (called "segues") between different views.
On top of being easier to design and implement, another advantage is that, if in the future you want to change the design of your application, you don't have to trawl through all your code and manually update each view connection.
Related
I am making code for iPhone. My first screen has only one button with text Menu. When user will click on this button next screen is coming with multiple navigation bar.Each Navigation bar has their own Text information which are being selected after clicking on any Navigation bar.
How i should to design it for iPhone ? Please give me concept. Should i take multiple views ? If i have multiple views how will i hide and show on button click event ?
Thanks in advance.
You will have to adapt your user interface to comply to how Apple wants an app to work, look, and feel - or make your own custom viewcontrollers. Even then, you might not get the exact behavior you want.
My hottest tip is to look at similar apps on appstore and see how they are navigated.
I don't get a picture in my mind from your description, but it seems you want what is called "drill down". This is best done with tableViews.
You can't have multiple navigation controllers on the same "screen"; it doesn't work like that on the iPhone. Instead, what you have is one single Navigation controller, that controls the pushing of views. You decide which sub-view to push depending on which selection the user makes, and the Navigation controller handles the rest of the interaction with the user to let him or her navigate between the views.
Example structure:
Window-based app
+-MainWindow.xib
| +-First view with button
| +-UINavigationController
+-tableview1.xib
+-tableview2.xib
+-any more views you need.
Make the app delegate a <UINavigationControllerDelegate> and declare navCt *UINavigationController, and connect it in Interface Builder. You can then write a pushVC method, which takes as argument a UIViewController *vc. It does a [navCt pushViewController:vc animated:YES];
Connect the button to an IBAction, which then calls the method in the app delegate, [PushVC myVC], where myVC refers to any viewcontroller in your app, in this case table view 1.
In this table, on didSelectRow... event you can use the same method to push the sub-view table view 2.
I think this is minimum code if you are unsure about iPhone app design. Either way, I hope it gives some ideas.
You should read about UINavigationController, UITabBarController, UIViewController.
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html
You almost always make one view pr. viewcontroller.
I'm building an iPhone app and I'm sort of confused about which approach should I choose for views and controllers.
I would like to have a tabbar at the bottom with three options. I would also like to have a main view displayed when the app shows (along with the tabbar) but I don't want this view to be part of the tabbar options.
So, when the app begins, the tabbar has no option selected but the main view displayed. When a tabbar options is selected, in its top bar it should display a back button to the main view. When the back button is pressed, the main view display again with no tabbar option selected.
Which approach should I choose?
Hope it makes sense.
Thanks.
I understand what you're trying to do, but you shouldn't do that. I don't like that design at all. You should have one navigation controller for each tab.
You should probably read Apple's Human Interface Guidelines as it's possible they would reject your App if they thought such an implementation with a TabBarController was confusing.
As an alternative, you could possibly have the "main view" as you call it accessible with a button in the Navigation bar at the top and then add that to all three tabs. Not necessarily a better design but you probably wouldn't be breaking the guidelines.
A better alternative might be to use a UIToolBar at the bottom instead of the Tab bar which has the three buttons spawning your views modally which can then be dismissed as you suggest.
Remember though, your App's users have built up a knowledge of how App's are generally supposed to navigate, feel and control so you should think carefully before deciding to go against that.
Firstly, I think you should reconsider giving your Main View it's own tab. That way it's a no-brainer for the user to return to that screen. BUT, if you STILL don't like that idea, read on...
The UITabBarController has the unfortunate side effect of not being able to be removed once created (even if you delay it's creation by instantiating it programmatically).
SO...
Option 1: Make your MainView a modalPresentation sub-view, displaying it ON TOP of one of the views in your tab bar (hiding the tabs until you're ready to show them again).
Option 2: Give a subview of your first tab a...
mySubViewController.hidesBottomBarWhenPushed=YES;
This will make the UITabBarController disappear temporarily (just on that view, until you're ready to show the tabs again).
Both options seem kinda messy to me, but they are possible. Depends on how well you execute them, I suppose.
Hope this helps!
You could add the main view as another tab.
OR
You present the main view modally when the app starts over the tab bar views.
The first option would be used more if the view holds the same kind of content as the tabs, for example if the app was an online store, the tabs would be Categories, Search and Recently Added, with what you call the "main view" being the Home page (showing offers or something). (So all the views/tabs would be showing products on the store)
The second option would be more if the content of the main view is different to the tabs.
Keeping with the online store example, if the tabs were Categories, Search and Recently added and what you call the "main view" being a login/logout screen. (so the tabs would be showing products, but the modal view ("main view") being more admin related, and it's main purpose not being to display products.
I'd like to display some small tutorial dialogs on top of my exiting views. I want to be able to see my existing views behind these smaller views.
Do I have to use view controllers in the same I way I would me normal views, and presentmodalviewcontroller etc ?
I haven't tried making a smaller view in interface builder before.
Also, say I want to move to another one of my existing views, full screen, while in my tutorial view. How would I close my tutorial view move to the next full screen view and launch another tutorial view ?
Example code or pseudo code would be welcome.
If your tutorial dialogs are just text, you could use UIAlertView to show the information to the user, so they can just read it and click the OK button when they're done. It's a very easy way to show some text to the user.
If you need to include images or other interactive items in your tutorial dialogs, the easiest way might be for you to just have your fullscreen view's view controller create a new view and put it up. So in this case, you'd create your view in Interface Builder, and when you want to show it, instantiate it using -[UIBundle loadNibNamed:owner:options:] and add it as a subview of your main view. Of course, it may even be easier to create the tutorial view programmatically from your view controller rather than using a nib for them at all.
Regarding the question of moving on to another fullscreen view, you would probably want to look into embedding your view controllers in a UINavigationController. This would allow you to push from the first controller to the second very easily, and the user would be able to just tap the Back button to get back to the first. If you're not looking for a navigation bar type of interface, you could present the second view controller as a modal view controller by calling -[UIViewController presentModalViewController:animated:] on your main view controller. This will pop up the second view controller fullscreen, and the user can dismiss it when they're done. Check out Apple's great documentation on UINavigationController to get a feel for how to use that:
http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/NavigationControllers/NavigationControllers.html%23//apple_ref/doc/uid/TP40007457-CH103-SW1
I would think that you could use existing UIViewController and simply add a new UIView that is of desired dimensions, that sits in front of other views and which is non-opaque and has alpha less than 1.
If you want a general purpose tutorial mechanism that can be placed atop any one of many UIViewControllers, then you would want to extract the navigation logic, etc.
Sorry, no code - just a few quick thoughts.
I'm tryin to grasp the fundamentals of Cocoa (Iphone) MVC design, but it's being quite tough. I've come accross several example applications, from the web, books.. but I've found nothing related to what I'm searching, since most of the examples just present a simple app (ie, a viewcontroller with a flipside viewcontr and a bit more..). So let's see if someone is willing to help me out in pointing me to the right direction:
My goal is to build a somewhat complex app. I'd like to have the following relation of views:
Presentation view (which would have a controller loading several memory intensive vars)
Main menu view: different options that would result in entirely new complex views. In example, a Begin option to initiate whatever the app permits to do; a second option to do another complex task with different views and actions within it, an Options option to configure options; a help option, an about option, etcetera..
In a first approach I tried to embed several rounded buttons in a view under the MainWindow nib with an associated app delegate. This approach though posed the question to how I manage to switch between views/viewcontrollers. After having uncaught exceptions because I probably don't fully understand the basics, I tried to move on to more 'simple' things.
Then I came accross the Navigation and Tabbar default Cocoa controllers. I don't want a tabbar, although it could come well for other parts of this app. Then the nav controller is what I think is most suitable for this case.
Thus, am I on the right spot if I build a hierarchichal app where its root is a nav controller? I've seen I can customize the main view to display a customized table, where each cell coud act as a button to spawn its respective view+viewcontroller. From here then I can keep building the 'leaf nodes' of this hierarchy of views/viewcontrollers, right? Eventhough I don't like the animation that by default provides the nav controller, I assume I can get rid off it..
So to sum it up in an easy way: I'd like to obtain a menu like those that can usually be seen on Cocos2d apps.
It's frustrating to ask this, I know it has to be easy but I find the documentation quite a mess aswell as the examples I've seen.. GUI programming it's being a tough learning curve :/
Thank you for any answers in advance, and excuse me for this long post.
Thus, am I on the right spot if I
build a hierarchichal app where its
root is a nav controller?
Almost. A nav controller (despite being a subclass of UIViewController) does not control views but rather other view controllers. The nav controller pushes and pops the view controllers which in turn causes the controller's respective views to load and become visible.
Therefore, the "root view" is actually the view that is controlled by the view controller that is in the nav controller topViewController property.
The app delegate serves to hold the nav controller and to tell it which view controller to push on the stack first. After that, the view controllers tell the nav controller when to push and pop them.
Otherwise, you're on the right track. You should always attempt to present information on a mobile platform in an hierarchal manner starting with the most general at the top and growing more specific as you drill down.
And you shouldn't be embarrassed at finding this confusing. 90% of the introductory/tutorial info out there, including books and Apple resources, focus on the gee whiz aspects of the interface and tell you next to nothing about the actual application design or how all the parts fit together conceptually.
You right about how little information is covered about app delegates to nav controllers. I been digging and trying to get all my screens linking etc. Having alot of fun watching my apps start to look more then just some Frankenstein monster UI. ahahah
The Itunes dev videos are great for looking at push and pop stack UIviews theory. I found they moved a little fast but after watching them the hands did make more sense. I have been forcing myself to watch them all and get a really good feel for whats going on. Hopefully have a nice app working soon.
Im a budding iphone developer, and doing my best but i have a query regarding the UINavigationController.
I have a tab bar app, with 3 tabs.
The 1st tab has five UIButtons, each loading a different "section" of the app, and each section will have a number of views.
The other tabs simply display some info.
as users select any of the UIButtons on my first tab i am using [self.view addSubview: xxxxx];
and as users navigate away from this view i use [self.view removeFromSuperview];
My question is:
Is this a bad way to do things? should i use a navigation controller? The reason i have not used one is because i wanted a custom looking UI and i understand that the navigation controller forces your design a little.
And on top of that i will be using core data to implement persistent storage.... will my way of implementing this application cause an issue with core data?
Any help regarding thsi would be highly appreciated.
Cheers
Tom
First, if you don't need a navigation controller, then don't use it. You shouldn't feel bad about it. That said, I think UINavigationController doesn't impose a specific UI on you at all. It's very easy to hide the navigation bar and implement any UI you like. The thing that UINavigationController does impose is a modular design: each view is managed by a separate view controller and takes up the full screen. Only you can answer if this design is suitable for your app. If it is and if your app is designed around a hierarchy of views, a navigation controller is probably a good choice.
As you said: when one of the five buttons is tapped the users is navigating to another view and the five buttons disappear. This is what the navigation controller is designed for and helps you manage the memory better than simply adding and removing views (depending on how many views are added/removed it might also be better on performance). As Ole points out the NavigationController is highly customizable and doesn't impose much.
A NavigationController gives you more flexibility down the road: say you want to add another hierarchy level after one of the buttons has been tapped in version 2.0. Then you will find that your MainView will be growing as you keep adding views to it. A UINavigationController keeps your code well structured and lets you extend the navigation later one.
CoreData is very flexible and UI-independent. You shouldn't have to worry about this.