My app features an UITabBarController, which brings up some views.
In the app delegate, I have to pass a (custom) model to it. Is the best way to do so is subclassing, or is there some better method?
If I put the model (e.g. Notes) into my UITabBarController, how do I access it from view controllers?
I'm not really sure why you would want to pass a different model to the UITabBarController. The only thing tab bar controllers do really well is managing the tab bar. Their "model" is basically a list of ViewControllers which they then present to the user if he taps a tab bar icon.
In the documentation Apple says the UITabBarController class is not intended for subclassing, but you could still do this if it were neccessary.
But if you just want to do this because you have convenient access to the tab bar controller from within your other view controllers, then I'd recommend leaving the tab bar controller allone and implementing some sort of a NoteManager class (probably as a singleton) and simply using it from your other view controllers.
Related
I need to have a Tab Bar navigation at the end of a branch in the Navigation Controller, as illustrated basically below. (I am using storyboard for structure, and doing everything else programmatically.)
Is this acceptable and stable? (Xcode seems to have no objections.)
Could I put another Tab Bar nav, inside the initial Tab Bar nav, so there would be 3 tiers:
Nav Controller > Tab Bar > Tab Bar
Thanks for any suggestions and advice.
You can do all of this. Xcode won't object. The various view controllers can all contain each other, and will behave (mostly) as you expect.
You might want to think about whether you should do all of this. The View Controller Catalog makes reference to the fact that tab bars always wrap navigation controllers, not the other way around, and similar statements have appeared in the View Controller Programming Guide.
What's more, the particular view controllers that Apple provides generally have an expected user interface, one that users have grown very accustomed to seeing in other apps. Combining multiple tab bar controllers might break those expectations - hierarchical content like that is generally contained in navigation controllers instead. Consider reading through the Human Interface Guidelines before proceeding with this structure.
I believe you can. Tab bar and Nav controller are both container controller and they can be used to contain any kind of controller: container controller or content controller. Have a look to the ref doc for more info.
Not really AFAIK. But you can use a UITabBar NOT a UITabBarController wherever you want.
See this blog article: http://www.alexmedearis.com/uitabbarcontroller-inside-a-uinavigationcontroller/
Sorry for the vague title!
I am trying to achieve the following functionality: A user is first presented with a UINavigationController containing a UITableView. When the user taps a cell in the table view, I want to push a new view which contains a UITabBarController (that'll stay visible regardless of the currently visible UIViewController) and a UITableView again, that people can again select a cell from and which will then again push to UINavigationController.
If a user selects a tab from the UITabBar, I want the first screen (without the UITabBar) to be the one that users can go back to, not the tab they just came from. Also, if a user selects one of the UITableView items on any of the tabs, I want the back button to go back to the previously displayed screen (as you'd expect with a standard UINavigationController)
I've spent hours trying to find the answer to this and I just can't anywhere! I hope I haven't been too vague or confusing in my explanation.
James.
If your desired UX is confusing to explain here, imagine how your users will feel! I would reconsider the intended design.
From the View Controller Programming Guide:
An application that uses a tab bar controller can also use navigation
controllers in one or more tabs. When combining these two types of
view controller in the same user interface, the tab bar controller
always acts as the wrapper for the navigation controllers. You never
want to push a tab bar controller onto the navigation stack of a
navigation controller. Doing so creates an unusual situation whereby
the tab bar appears only while a specific view controller is at the
top of the navigation stack. Tab bars are designed to be persistent,
and so this transient approach can be confusing to users.
That said, you can probably hack something close to what you are talking about but you'll need to write a bunch of code to handle the navigation using the UITabBarControllerDelegate and UINavigationControllerDelegate methods and keep track of whatever state you need to know where you want to navigate to based on a user action. Odds are you'll end up with something complicated to code, maintain, and worse, use.
I am trying to develope an iPhone App for 3 months.
I found everything myself in books or the internet. Now I have a problem that I am not able to solve myself.
I would like to develope a tabbar application with 3 tabs.
In each tab is a navigation controller with a tableview.
The tableview loads the data from an XML file on the web. The difference between each tab is only the difference XML-url. The tableview and function should everywhere the same.
What have I done?
Created a tabbar application
Put 3 Navigation Controller in the Tab Bar Controller in the MainWindow.xib
Every View in each Navigation Controller points to the same "TableView" class
Now it loads on every tab the same tableview. But I just want to change the XML-URL which is loaded. But I dont know how to implementate this.
I hope that somebody can give me a hint? Thank you!
Are you sure you need a Tab Bar? You could just add an additional level of navigation on top for the sources. So your navigation controller stack would be like
UINavigationController -> SourceViewController -> ListViewController -> rest of your navigation stack.
ListViewController is a subclass of a UITableViewController which is passed the source url based on selection from SourceViewController which can be a subclass of UITableViewController too. This will save you of the repetition you are trying to avoid and is more likely a better option for the thing you need.
Now if you insist on using a Tab Bar, your stack will be more like –
UITabBarController which will have three instances of UINavigationController each with its own instance of ListViewController which like before will be initialized using a source url.
Now it may be smarter to reduce it to a single ListViewController and attaching all the navigation controllers to it. You can do this using the -tabBarController:didSelectViewController: method in the tab bar delegate. On every tab change/call, you clear the current cache that is providing data to the table view and load the appropriate cache based on the source XML of that tab.
Usually state is preserved on tab changes but using this structure you will have to do additional work to get that.
I have the following structure in my app, is this a correct/valid way of doing it?
UINavigationController attached to the window, the rootcontroller in this navigationcontroller is a UIViewController that presents a tableview. When a user taps one of the rows a UITabBarController is pushed on the stack.
This works, however I began to be unsure when I read this:
Because the UITabBarController class
inherits from the UIViewController
class, tab bar controllers have their
own view that is accessible through
the view property. When deploying a
tab bar interface, you must install
this view as the root of your window.
Unlike other view controllers, a tab
bar interface should never be
installed as a child of another view
controller.
This is not recommended, but it should be OK. The aweful Wordpress app also does this. This depends on the design of your app.
I'm not shure about Apple's approval.
The reason why this is not recommended (and thus might not get approved - now or at a later point!) is user confusion.
Users are used to regard the tab bar as top-level navigation. So if dig down using the table and navigation, and then getting a UITabBar, this is horrible for navigation as the user doesn't know what to expect.
The solution here, of course depending on the use case, is a "switch" in the navigation bar or a toolbar. UISegmentedControl would be a natural choice.
I am sure this is very simple, yet I am stuck...
I have created an application and added UITabViewController (dragged in from the library in Interface Builder. My application has 3 different views, clicking on appropriate tab brings the different view. So far so good.
I want to convert one of the views to be a UINavigationController: basically a table with the option to delete rows (so UINavigationController would need to have a button "Edit" on top).
I saw many samples which would do either 1 or 2, but not both.
How would I combine it, keeping in mind that I have used provided UITabViewController and did not added UITabBar directly to the view.
Thanks
If you are using Interface Builder, you should be able to just drag and drop a navigation controller into your tab bar controller as a child controller. The next tab bar item should be generated for it automatically from that.
You can also do this programatically by just creating however many UINavigationControllers you need in an array and assigning that to the uitabbarcontroller appropriately.
I actually don't like this method of combining the UINavigationController and UITabBarController since the tab bar controller must always be visible, which can be really confusing sometimes.
Instead, I recommend you make your own custom UITabBarController (Tab bar controller inside a navigation controller, or sharing a navigation root view) which you add to the navigation controller. I personally don't know why Apple didn't do this; hopefully this is the standard way in 4.0 :)