I have a requirement to implement an app that has a navigation bar like bar at the top of numerous screens.
It has an icon on the left, some text, and some buttons on the right thus these would map well to a navigation item's left bar button items, title view, and right bar button icons.
However on most of the screens the content of the bar remains the same - i.e. a back button and title change would only appear occasionally for some screens, and on others the navigation bar would be present but is not actually used for navigational purposes.
Is the best of implementing this to configure a UINavigationItem, if so as there are multiple screens and multiple view controllers is there anyway the same UINavigationItem can be shared? That way I can configure the UINavigationItem in the RVC and keep it there as different view controllers get pushed, replacing it where need be when a back button does actually need to appear?
If this isn't the best approach then what alternatives are there? I experimented with making my RVC a container view controller and adding the bar as a view of that, that works for the immediate child view controllers but not for grandchild view controllers (which would take up the entire screen and not the portion alloted to them by the container view).
The navigationItem in UIViewController is readonly, so you can't have a single shared UINavigationItem shared between view controllers. You could have a base view controller class that manages setting the navigation item that you derive all of your view controllers from. To keep your classes from getting too coupled you could have it update the contents of the navigationItem from a NSNotification. Then you can just post a notification when you need all of the navigation items to be updated.
Related
I have a simple Navigation View Hierarchy that has 2 views it goes between. I wanted a customized navigation bar, so I have the default one hidden, and I've implemented a Container View which is shared between the 2 views in the nav hierarchy.
Everything works as I want it to, except when I segue to the lower or higher view the top bar appears slides away and reappears on the new view. I would like it to appear stationary when I push or pop to other views in the hierarchy.
Is there an easy way to do this? Or should I delete my custom shared Container View and try to make this work with the Navigation Bar (which I have currently "hidden")?
I had to do this for a client once. The way we did it was, like you said, make an encompassing view controller that housed a container view. Within this container view, we embedded a UINavigationController and would manually pop and push UIViewControllers to its navigation stack. Of course you want to hide the UINavigationController's nav bar.
It sounds like you sort of implemented this, but instead you just embedded a plain old view controller inside your custom navigation controller, and then segue to another view controller that is also embedded in the custom view controller? Ideally you want one instance of this custom nav controller with an embedded UINavigationController. I believe you will have to do all the view controller transitions programmatically.
Opinion: Personally, I would recommend against doing this. I believe that an app should feel like an extension of the OS it's on. A user should feel it's a part of their phone. Using the native navigation bar also decreases the level of effort a user is required to put forth to understand your app.
I know you're thinking "but it's just a nav bar" but we're talking about the same people that will potentially uninstall an app if it takes longer than 2.5s to load.
I wanted a customized navigation bar, so I have the default one hidden
That's your mistake. The way to get a customized navigation bar in a UINavigationController interface is to initialize it with init(navigationBarClass:toolbarClass:). Now the built-in navigation controller is using your navigation bar! And from there on, all will be well.
https://developer.apple.com/reference/uikit/uinavigationcontroller/1621866-init
I'm having trouble getting a UIToolbar to appear at the bottom of the screen when my app loads. Regardless of how I position the UIToolbar and regardless of the constraints that I have put on the bar, it always appears in the middle of the screen. I have my navigation bar situated correctly, and I've never had trouble situating UI elements in IB before (although I'm new to iOS programming). Any ideas on how to make sure the toolbar stays in place? Thanks.
You're probably not playing the game correctly with UINavigationController. See:
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UINavigationController_Class/
Displaying a Navigation Toolbar
A navigation controller object manages
an optional toolbar in its view hierarchy. When displayed, this
toolbar obtains its current set of items from the toolbarItems
property of the active view controller. When the active view
controller changes, the navigation controller updates the toolbar
items to match the new view controller, animating the new items into
position when appropriate.
The navigation toolbar is hidden by default but you can show it for
your navigation interface by calling the setToolbarHidden:animated:
method of your navigation controller object. If not all of your view
controllers support toolbar items, your delegate object can call this
method to toggle the visibility of the toolbar during subsequent push
and pop operations. To use a custom UIToolbar subclass, use the
initWithNavigationBarClass:toolbarClass: method to initialize the
navigation controller.
EDIT to include answer to question in comments:
No code needs to be written to do all this. You can set "Shows Toolbar" in the Attributes Inspector of your Navigation VC. You can then drag individual UIBarButtonItems onto particular VCs (on which a toolbar will suddenly appear) and do the usual outlets and actions with them.
I'm trying to create a tabbed application with navigation elements inside the tab bar, as seen in the picture below (the red bar) using Swift/XCode 6.2. Basically those three icons in the middle will direct the user to different view controllers. The other two icons would be context-based. For example, on a table view page you would see the menu icon and add new icon as seen in the image. However, clicking on a row would change the menu icon to a back icon, and the add icon to something else.
That's the general idea, but I'm having a very hard time implementing something even close to this. The first issue is that whenever I embed a view in a Tab Bar Controller, I can't move the tab bar to the top. However, when I create a custom UITabView in a View Controller, Control + Click and dragging a Tab Bar Item to another view doesn't create a segue. I haven't even begun to tackle having the navigation elements inside the bar.
I guess what I'm asking is just for a little guidance on what route to take to tackle this. I'm assuming I can't use a Tab Bar Controller or Navigation Controller because it doesn't seem like I can customize them all that much. So custom Tab Bar and Navigation Bars, and then implemnt the segues and button changes programmatically?
Thanks.
I will try to guide you from an architectural perspective (so you won't find much code below).
Using a UITabBarController
In order to achieve what you are suggesting, you are right you cannot use a UITabBarController straight away, among several reasons, the most immediate one is that they are meant to be always at the bottom and you want it in top (check Apple's docs). The good news is that probably you don't need it!
Note: If you still want to go with a UITabBarController for whatever reason, please see #Matt's answer.
Using a UINavigationController
You can use a UINavigationController to solve this task, since the UINavigationBar of a UINavigationController can be customized. There are multiple ways on how you can organize your view's hierarchy to achieve what you propose, but let me elaborate one option:
To customize a UINavigationBar's to add buttons, you just need to set its navigationItem's title view:
// Assuming viewWithTopButtons is a view containing the 3 top buttons
self.navigationItem.titleView = viewWithTopButtons
To add the burger menu functionality on a UINavigationController you can find several posts on how to do it and infinite frameworks you can use. Check this other SO Question for a more detailed answer (e.g. MMDrawerController, ECSlidingViewController to mention a couple).
About organizing your view hierarchy, it really depends on if when the user taps one of the main top buttons, it will always go to the first view controller in the new section or if you want to bring him back to the last view in the section where he was.
3.1 Switching sections displays the first view of the new section
Your app's UIWindow will have a single UINavigationController on top of the hierarchy. Then each of the 3 top buttons, when tapped, will change the root view controller of the UINavigationController.
Then, when the user changes section, the current navigation hierarchy is discarded by setting the new section view controller as the UINavigationController root view controller.
self.navigationController = [sectionFirstViewController]
3.2 Switching sections displays the last displayed view in the new section
This will require a slightly modified version of the above, where your each of your sections will have its own UINavigationController, so you can always keep a navigation hierarchy per section.
Then, when the user taps one of the top buttons to switch section, instead of changing as previously described, you will change the UIWindowroot view controller to the new section's UINavigationController.
window.rootViewController = sectionNavigationController
Using a custom implementation
Of course, the last and also very valid option would be that you implement yourself your own component to achieve your requirements. This is probably the option requiring the biggest effort in exchange of the highest customizability.
Choosing this option is definitely not recommend to less experienced developers.
I'd like to take a stab at this--I think it is possible to use a tab bar controller here.
Your topmost-level view controller will be a UITabBarController with a hidden UITabBar.
Each tab is contained in a UINavigationController.
All view controllers in the navigation controller will be a subclass of a view controller (say, SwitchableViewController).
In SwitchableViewController's viewDidLoad, you set the navigation item's title view (i.e. whatever's at the center; self.navigationItem.titleView) to be the view that holds the three center buttons. Could be a UISegmentedControl, or a custom view.
Whenever you tap on any of the buttons, you change the topmost UITabBarController's selected index to the view controller you want to show.
Issues you may encounter:
Table views inside tabs will have a scrollIndicatorOffset at the bottom even if the tab bar is hidden.
Solution: Play around with the automaticallyAdjustsScrollViewInsets of the tab bar controller, or the inner view controller. https://stackoverflow.com/a/29264073/855680
Your title view will be animated every time you push a new view controller in the navigation stack.
Solution: Take a look at creating a custom transition animation for the UINavigationController.
What is the best approach for when you want the same buttons (and their functionality) to appear in the navigation bar of a navigation controller when views are pushed and popped. For example, in my app I want a 'user settings' button to appear in the navigation bar regardless of the view that is currently at the top of the stack. When the button is tapped a popover appears which displays a list of specific settings. Do I have to set up this functionality for each view that can appear in the stack? Or is there a way to set it up once and allow it to appear for all the views in the stack?
I think the easiest way to do this is to subclass UIViewController. Have all the views that need to have this behavior inherit from the subclass.
I have an application with 5 UIViewControllers each inside a corresponding UINavigationController, all tucked inside a UITabBarController that displays 5 tabs at the bottom of the screen.
I want to display another UIViewController (inside a UINavigationController) when a dialog button is pressed.
This view should only be loaded and unloaded programatically; i.e. it should not appear in the tab bar. However, I want the tab bar to be visible always.
If I add the [UINavigationController view] to [self window] the UITabBar is covered. If I add it to any other layer, the UINavigationController adds on the compensation it has for the status bar so appears further down than expected.
A solution would be to have the 6th UINavigationController added to the UITabBar with the others, but with its tabBarItem hidden. Then I can show it and hide it using the tabBars selectedIndex property.
Accessing the tabBarItem through the UIViewController shows no obvious way of doing this.
#wisequark, I think you completely misunderstood and you have almost rewritten the architecture of my application. However I have a separate navigation controller for each view as they are mutually exclusive and there is no concept of "drilling down".
#Kendall, This is what I expect I will have to do - have the modal view appear with a hide button to bring back the normal interface. But it would be nice to keep the tab bar always visible, so I was just wondering if anyone knew of a way.
It sounds as though you have a mess on your hands. A UINavigationController is a distinct object that is very different from a UITabBarController. In general, your application should have a tab controller, one of who's tab's loads a UINavigationController which in turn loads it's views - not that both maintain management over the different views. It is also improper to refer to the display of a UIViewController as such an object doesn't have a visual representation. In the case of a UINavigationController, the navigation controller object is responsible for displaying a navigation bar and a table view (in the most common case) and for managing the display of all the views in the navigation hierarchy. It itself has no corresponding representation on screen. Similarly, a UITabBarController presents a tab bar and is responsible for the loading and unloading of the views and/or view controllers attached to the tab buttons. If we were to present this as an image, it would look something like this -
alt text http://img.skitch.com/20081112-2sqp7q4wafa34te1ga337u4k8.png
Well, it sounds like what you really want to do is present a modal view with the tab bar still visible. You could add your view as a subview of the tab bar controller's view. The tab bar's view is, oddly enough, not the tab bar itself but rather a view containing the tab bar and the selected item's view.
Alternatively, you could try calling presentModalViewController:animated: with the selected tab (i.e. [tabBarController.selectedViewController presentModalViewController:animated:]) as the receiver instead of the tab bar. I seem to recall doing this once (quite by accident) and the tab bar remained visible.
One more thought: since each of your five view controllers is a UINavigationController, you could always pushViewController:animated: onto the selected view controller, then hide the back button. Your view will just appear without animation. But you'll need to remember to pop your view controller off the stack whenever the user switches to another tab. That might take a bit more work.
The best idea I could think of would be to either push a modal navigation controller for your view (which would hide the tab bar which you do not want), or to get the tab bar controller current selected view controller (really your navigation controller for a tab) and push your new view controller on there - and then pop that view when another tab is selected with a tab bar delegate.
It seems wierd to me to push the view onto random tabs though, if the view is created from a dialog that is modal, I don't see why the view itself should not also be modal and hide tabs.