I'm in the process of learning and designing an app for our company. At its heart, it has a list of "alarms" which when clicked on, goes to a more detailed view with a toolbar to perform tasks upon that "alarm".
I'm having a devil of a time working out how to structure this application. I have something that works currently (i'll explain it in a sec), but now I'm about to hook up the data source for the table and I'm getting myself lost.
At the main screen, there is to be a list of "alarms". This list should be able to be filtered with 3 categories (All, Category 1, Category 2) where the categories are subsets of all the "alarms". I've implemented this using a TabBarController.
Within each tab, I've got a NavigationController (to handle the navigation of between the list and the details) and it's main view is a custom UITableViewController that contains the custom table view.
As described, when you click a item, it navigates to a detailed view. This is all currently working but I'm concerned about the structure.
It's pretty obvious that I have a fair bit of duplication with the 3 different NavigationControllers, but I've read that subclassing the NavigationController is not recommened.
My questions are:
Is there a better way to structure this application? Is there a better filtering method (thats quick and easy) instead of a TabBar?
Where should the tableview datasource go? Most examples I've seen have it being created in the AppDelegate and then passed directly to the tableviewcontroller. My custom tabelviewcontroller is a couple of levels down the controller chain, how do I pass the datasource to it, or can I make the datasource "static"?
I hope that all made sense
Sounds as though you want one navigation controller and table view controller with a segmented control at the top to switch between the different data views. For an example of this kind of layout have a look at how the App Store app works when you select the Featured tab - it has a segmented control to switch between New, What's Hot and Genius.
Related
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.
I have a very large form to build in my ipad application and I'm note sure which approach( between create multiple views in or multiple viewcontrollers ) to follow. Well, I have decided to split may form in logical sections, so I want use a splitviewcontroller with a root( a tableviewcontroller with the sections) and multipleviecontrollers for each sections. When the user select a row in tableview I will show the correspondent viewcontroller. I'm saving a reference for each viewcontroller in my app_delegate and the app_delegate also is the responsible for change the viewcontrollers. Is this the best approach? There is other approach to follow? About the multiple view I was thinking to put multiple view in the same xib file and then choose based in tag as the use tap the row in rootviewcontroller's tableview.
Thanks in advance. And sorry for my bad english.. Learning!
I will say this on the subject: currently, having multiple view controllers on the screen at the same time can be problematic if you're not using one of Apple's existing classes, such as a UISplitViewController.
The main issue is that important events your view controllers will want to respond to (rotation events, etc) won't be passed down to them. It's not a huge pain, it's just something to need to take into account - you'd typically create your own parent view controller that could pass these events down to its children.
Now, you are using a split view controller, so alls well on that front. There is no provided way for detail and master controllers in a split view controller to communicate with each other, but Apple recommend you employ a standard delegation pattern. If your application is fairly simple this could certainly happen in your app delegate as you do now.
If you're targeting iOS 5 only there are some changes that are relevant regarding multiple controllers on the screen at the same time, but I can't discuss them on here because of the NDA. You should go to Apple's developer forums (devforums.apple.com) to learnmore.
Sounds like I'm trying to do the same thing as you (large insurance forms here, how about your project?) Unfortunately I can't help out as you're a bit ahead of me. I've been able to flip back and forth between 8 detail views by tapping on the 8 rows in my UITableViewController, without keeping a reference to either the current or previous one anywhere. The data I enter into various TextFields stays where it should.
I currently have a xxxViewController.h/.m and corresponding .xib file for each detail view. That's an awful lot of code, but I couldn't see any other way to do it. Now I'm having a problem getting my button pressed handlers to fire. Also I've still got to put a database behind these screens.
Were you able to overcome your issue?
Thanks,
Jeff in Alabama
In my iphone, in the section where I can make a call, I can view recent calls and I can also view my contacts.
I am referring to the contacts application.
I'm watching the stanford iphone vidoes, and they recommend creating a seperate NIB file for each view.
From what I understand, each nib/view will be managed by its own subclass of UIViewController.
Can someone, at a high level, describe what the contacts application might be comprised of in terms of nib's, controllers and views and how they would work together?
The contacts app is, unfortunately, a bad example. It's functionality is implemented at a lower level in the OS, as it is shared between the address book app, the phone app, and it can be implemented in your own app if you wish. Thus, the app is really just another front end for the feature.
Basically, the app is a UITableView with search that sends you to a UIView containing a UITableView and some text / image fields. Of course, there are editing and creation buttons to handle CRUD, but basically that's it. Each page would have it's own UIViewController and NIB file (assuming Apple follows their own directions, which they may not) ;)
Underneath, you have a core data store, but there's no much complexity in the data structure there, either. If you really want to analyze the database file, that's possible as well.
Hope that helps
At a high level, you have a UITabBarController that handles the tabs along the bottom and the switching of the five view controllers. Each of the view controllers, with the exception of the "Keypad" tab, uses a UITableViewController as the root controller of a UINavigationController. And it looks like, for the most part, where you are in the UINavigationController "stack" is remembered for each tab.
Each of the UITableViewControllers have a fairly simple implementation of the standard UITableViews. The implementations of UITableView are probably canonical examples of how to use UITableViews -- namely, what action to trigger depending on whether there's a disclosure button and what gets clicked.
Hope this helps!
I have a User Filter section of my iPad app. There is a segmented bar with 5 buttons for 5 types of filters.
Clicking each of the buttons will load up the respective view..
My question is.. would the best way to handle the UI of each filter to have several views in this nib and load/unload accordingly.. or would best practice be to create the information in a scrollable view?
below is the setup..
http://imgur.com/iuufU.png
Thanks in advance...
Generally, go with separate views. The Scrollable view is an approximation of what you're trying to achieve (by the looks of things), whereas the separate-views more closely reflect your aims.
Some typical dvantages:
if you change your UI design, e.g. if one of those filters has to go in a different page, but 4 stay here ... then it's easy to move the whole View without changing the eixsting ones.
you can put each view in a separate NIB file (if they're different), or loaded from a separate ViewController instance (if they're the same), and you get some of the advantages of Apple's automatica memory management of VC's / NIBs.
Usually, people start with the same view for each filter, using a single VC class (instantiated multiple times, once per tab).
Then, as the app evolves, they find that one tab needs a different layout, so they add another VC class, and only need to update the alloc/init line for that one tab.
Ok so basically I have a UITabBarController as my root view controller. I have three tabs that will all have UINavigationController objects nested in them, controlling three table views each.
Each mode will access the same database in the same way, but just sort by different variables. Very similar to the way the iPod app works - whether you narrow down your search by Artist or Genre, you end up at the same "detail view" (the song playing).
My question is, should I link all three tabs in Interface Builder to the same UINavigationController, but just populate the table depending on the selected tab? Or should I create completely independent objects for each tab, and copy and paste code?
The first way seems more efficient and flexible, but the second seems like it will be a little more explicit and easy to read!
Thanks for any help :)
I think clearing the navigation controller stack on every tab switch (assuming it is not hidden when the non-uppermost navigation child is shown) would be much more resource-consuming than having all three/four UINavigationControllers available all the time (mostly for quick tab-switching).
Further, if the owning UINavigationController is the only object that retained (owns) the UIViewControllers on the stack, then you will also deallocate your UIViewControllers should you decide to reset the navigation stack (1-Nav scenario). Assuming of course they are not "statically" present inside a NIB.
TL;DR version
I'd use a separate UINavigationController for each tab, in a low memory-footprint app it will increase the visual performance of your tabs.