I've seen a lot of apps that have a universal search bar that always remains at the top of the app. I have implemented a UISearchBar with a UITableView in one view controller. I want to have the same search bar on other view controllers in my app. How do I link these other UISearchBars to the one I have already created? I.e., how do I configure these other UISearchBars so that they return the same search results and link to the same UITableView?
Nested view controllers may be what you need.
Define a “top view controller” that manages a “top view” containing a search bar and add your (table) views to the top view (using -addSubview: on the top view) and the associated view controller(s) to the top view controller (using -addChildViewController: in the top VC and on itself).
In Interface Builder, you can define a top view and inside it a “container view.” The system then handles the insertion of the subview and sub-view controller.
By defining a good view controller hierarchy, you make your app design more logical and clean. I’d recommend to take some time into investigating a good hierarchy before diving into coding.
A final note: the UISearchDisplayController is an object (apparently not a view controller) that superimposes a search bar above a view controller’s view. You might be able to simply apply it immediately above the top-most view controller (the one that is always visible, like a navigation controller). It’s worth looking into it, if you didn’t already. ;-)
An example
View controller hierarchy
XYZTopViewController (managing a XYZTopView)
UINavigationController (managing a private navigation view hierarchy defined by Apple)
XYZFirstPageViewController (managing a XYZFirstPageView) (the “root” view controller)
XYZSecondPageViewController (managing a XYZSecondPageView) (pushed by nav. controller when you need it to)
View hierarchy
XYZTopView
UISearchBar
(private navigation view hierarchy defined by Apple)
XYZFirstPageView
(your view hierarchy belonging to the first page/screen)
Since you only every have one window per app, and view's don't have
levels, you have to make sure that view stays on top of the hierarchy,
no matter what. One relatively easy way is to add it directly to the
window above the rest of the interface (the navigation controller):
How to show a uiview alway on top?
In applicationDidLaunch:
// After the main navigation controller or tab controller has been added
// either programmatically or in the xib:
UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0,70,320,44)];
[self.window addSubview:searchBar];
Related
I was going through Apple's documentation about navigation controller and find this point ambiguous and hard to comprehend.
It was written in this online documentation of navigation controller.
Navigation Controller Views
A navigation controller is a container view controller—that is, it
embeds the content of other view controllers inside of itself. You
access a navigation controller’s view from its view property. This
view incorporates the navigation bar, an optional toolbar, and the
content view corresponding to the topmost view controller. Figure 2
shows how these views are assembled to present the overall navigation
interface. (In this figure, the navigation interface is further
embedded inside a tab bar interface.) Although the content of the
navigation bar and toolbar views changes, the views themselves do not.
The only view that actually changes is the custom content view
provided by the topmost view controller on the navigation stack.
From that, my understanding is that inside this "view" property. There should be at least two subview inside this view.One is the navigationBar the other is the contentView of the current displayed viewController’s view. But while I am debugging only the navigation bar showed with another view called UINavigationTransitionView showed.
My question is, is this normal. Have I done anything wrong?
Second, what is the most common way to access current displayed viewController's view with only the reference to the navigation controller.
Thanks
UINavigationTransitionView controller contains one wrapper view which intern will have the current uiviewcontroller's view.
You can probably find this view as a subview of UINavigationTransitionView. However this is not the "right" way to do this. The proper way is to go through property "topViewController" and then take its view:
self.navigationController.topViewController.view
If there is another view controller or its view that you need, you have access to whole view controller's hierarchy across navigation controller through viewControllers property.
self.navigationController.viewControllers
More here:
https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UINavigationController_Class/index.html
I've seen a lot of other questions on here about adding a UINavigationBar to a UIPopoverController. All of the examples I've seen follow one of two patterns:
In the init or viewDidLoad method of the Popover subclass, you alloc-init a UINavigationBar directly, as suggested here. This method is a little hacky, and while it shows up nicely, if the popover is a UITableViewController, you have to mess with a bunch of things to make sure the navigation bar you just added doesn't overlap one of your cells.
Alternatively, a lot of post suggest creating a UINavigationController just before presenting the popover, as shown here.
With the second method, however, won't the popover be the only controller in the newly created navigation controller? And if my view that I'm presenting the popover from is itself already in a navigation controller, the popover will NOT be in that same navigation controller, correct? It seems to be that the more appropriate thing to do would be to add the popover being created as another controller in the navigation controller that already exists (and which the controller that presents the popover is already a part of). Is that possible? Or is there a reason why the navigation controller for the popover needs to be independent from the navigation controller for the presenting controller? Or am I totally missing something here?
You have many questions, young Skywalker. :)
Creating a UINavigationController and then embedding the controller you would like to present is the way to go.
Don't get confused by all the controllers involved here:
UIPopoverController is a construct that shows an existing UIViewController in an overlay like style. UIPopoverController itself even isn't a subclass of UIViewController. The name is misleading.
So UIPopoverController hosts another controller. In your case, we let it host a UINavigationController.
UINavigationController is a subclass of UIViewController. It is a container controller and can handle a stack of UIViewControllers.
On that stack we push one UIViewController: the one you want to display and garnish with a UINavigationBar. Since Mr. UINavigationController comes with a build in UINavigationBar, he's our friend.
There is no need to subclass UIPopoverController. You just keep one static reference to it around so you can dismiss the current open popover in case you want to present another.
It does not matter where you present the UIPopoverController from. It will always be a popover. Even if presented from an existing UINavigationController. Only if you use presentViewController: you will get different results depending on the controller you're presenting from (modal or pushed on top of the stack).
won't the popover be the only controller in the newly created navigation controller?
No, the popover will contain the navigation controller and the navigation controller will only contain its root view controller (which would otherwise have been added directly to the popover as its root).
You seem to be a little confused about the relationship between the popover and the popover root view controller...
the popover will NOT be in that same navigation controller, correct
Yes, correct. The popover is effectively a window floating above all other views
Or am I totally missing something here?
Maybe... The popover would usually be used for displaying something modal, transient and smaller than full screen size. Putting a navigation controller in the popover and adding views to it is the normal approach.
Adding a navigation bar to a popover isn't hacky. A navigation bar is just another regular view. That also means that using a UITableViewController with it, the navigation bar will overlap the table view, as the UITableViewController's view property just returns the controller's tableView property. If you want to add a navigation bar above a table view, without it overlapping the table view, use a regular UIViewController and add your navigation bar and table view the normal way. UITableViewController should only be used if your only view within that view controller is a table view.
Having said that, I do agree with others that just using a navigation controller without using its navigation features is the most common approach.
In my app I want to add a view much like the status bar, always onscreen at the top of each of my view controllers, displaying application wide data.
I really have no clue how I might achieve this so any suggestions would be really helpful. I;m sure someone must have chased this idea at some point?
Thanks.
What you're willing to do is fairly straightforward since iOS 5 using view controller containment, it allows you to embed child view controllers in a parent view controller.
In your case I would create a custom container view controller with two subviews: the content view and the statusbar-like view. The content view should display your current root view controller by adding it as a child view controller to your container view controller and adding its view as a subview to the content view. The statusbar-like view can then be used to display information that will be visible everywhere in your app.
You might want to read this documentation for further details:
Creating Custom Container View Controllers
You can create your custom view and add it as a subview to your keyWindow. This way it will always be visible. Another option is if you have tab bar controller or a navigation controller as your root view controller, then you can add that view as a subview to their respective view and it will always be visible.
I am creating a iPad App and it has several views to load data,but for one view i need to add split view. I dont need split views in other views. They are just detail pages. I search Through the net and found lots of tutorials based on iPad split view. But the problem is they all are creating a project as Split view project or they create a window base app and add slipt view to the delegate. I dont need to do that, I need to implement this split view only for one view. Is There any way to overcome this problem?
You can add the split view inside a Navigation Controller.
Even if the Split View is a container view controller and Apple recommends in the documentation that all containers should not be embedded in other containers, adding a split view inside a navigation controller works correctly and I never noticed any side effect in doing it.
Basically what you should do is:
- in the app delegate create a UINavigationController and use it as root view of your application window
- hide the navigation controller navigation bar if you don't want to see it (showing a split view with a main navbar on top is not nice looking...)
- then add your view controllers inside the navigation bar.
Example: imagine you have this application views sequence:
FIRST VIEW (full view = detail page)
SECOND VIEW (split view)
THIRD VIEW (full = detail page)
So you can represent FIRST and THIRD as standard view controllers (full screen), while SECOND will be a split view. Your app will be initialized by creating the main navigation controller, adding FIRST on it as top controller and using the main navigation controller as window's root view.
Than use the navigation controller push, pop methods to switch between these views or change the navigation controller "viewControllers" array directly if you don't want the recommended push/pop methods.
If you need to add special behavior to the navigation controller based on the type of view on top, just register your app delegate as navigation controller delegate (or a "main controller" object dedicated to this if you don't want to complicate your app delegate).
I am not 100% sure, but it seems to me that you can't use a SplitView just somewhere in your view hierarchy.
The Apple intended way is to use the SplitViewController as the top level controller. The left side of it can include a drill down mechanism with a navigation controller so you are ably to drill down hierarchies and the right side will present details for the item you select on the left side.
If you need a view with some kind of split mechanism in it, you probably have to code it yourself. Or even better: find some other mechanism you can use in your UI.
How are you switching your view hierarchies now? Maybe you could integrate your existing UI into a SplitViewController?
I understand that view controllers help control multiple views in an application, but I have trouble understanding when to use them.
If I have an application with a main page, several views with a "hierarchy" structure, and an about page not connected with the hierarchy, what files should my application have? An appdelegate, navigation controller and view controller? More than one view controller? Just a navigation controller?
Also, should they all be contained in one .xib file, or multiple .xib files?
Any help would be greatly appreciated.
Thanks.
A good habit is to have a UIViewController for each page you want to show. If I get the structure of your app you should have a main page (with many other UIViews inside it) and another page (about page). If that's true I suggest two UIViewControllers.
The UINavigationController is a subclass of UIViewController that lets you "navigate" among the pages. It's not strictly necessary but suggested (you can also implement your self a custom navigation system, but it's easier to exploit the one Apple offers you). Another navigation system is the one based on UITabBarController, if you want to take a look.
Assuming I get the structure of your app you should need two .xib file, one for each page you have.
The app delegate is conceptually different from a view controller, you'll have just a single app delegate, automatically created by Xcode (you can, of course, modify it to fit your needs).
Each "screenful of content" (Apple uses this term) should be handled by it's UIViewController or more likely a subclass of it. The point of view controller is to handle view appearing or disappearing (going on/offscreen), device rotation, memory management, navigating to other view controllers and so on. If you are creating your UI with IB, then each of those view controllers would most likely have it's own .xib file.
Each view controller has one view (it's view property) that acts as main view for each "screenful of content" to which you then add your subviews.
UINavigationController and UITabBarcontroller are there to help you control the hierarchy of your app. They only act as containers for other view controllers and don't contain any UI except navigation bar or tab bar. Using tab bar controller you can have multiple view controllers which act exactly like browser tabs. Using navigation controller you can have a stack-like navigation where new view controllers are pushed from right to left and are popped from left to right when user goes back to previous view controller. You can even have a view controller inside navigation controller inside a tab bar controller.
If you don't want to use tab bar or navigation controller, you can navigate through your view controllers by presenting them modally using presentModalViewController:animated: and dismissing by dismissModalViewControllerAnimated:. If you send YES for animated parameter of these methods, you will get an animation specified by the modalTransitionStyle property of view controller being presented or dismissed. Possible animations are slide in from bottom (default), horizontal flip of entire screen, fade in/out and half-page curl.
There are also some Apple-provided subclasses of UIViewController that help you setup your UI quicker like UITableViewController which is basically a view controller that contains a table as it's main view and conforms to 'UITableViewdataSourceanddelegate` protocols which are required to define how each cell looks and what it contains.
On iPad there is one additional container controller UISplitViewController and one additional way to present new view controllers using UIPopover.