Scenario:
We have a tab bar controller in the app.
Only one view controller has a different color style for the StatusBar, let's call this view controller VC1.
So I have added logic in VC1, viewWillAppear set the wanted StatusBar Color, viewWillDisappear reset the default StatusBar Color.
Issue:
Most of the time, different tabs have different view controllers, this is no issue of the status bar color changing.
But In one case, I will have VC1 shown in two tabs, in this case, when I switch tab, viewWillAppear got called first, which means the reset StatusBar style got called later, so after switching the tab, the StatusBar Color is wrong.
Is there a way to solve this? It seems the view controller life cycle is wrong in this scenario.
Look at UITabBarControllerDelegate. Using that, you can take action based on which tab is selected - such as changing the color of the StatsBar - instead of doing that inside the VC.
You use the UITabBarControllerDelegate protocol when you want to
augment the behavior of a tab bar. In particular, you can use it to
determine whether specific tabs should be selected, to perform actions
after a tab is selected, or to perform actions before or after the
user customizes the order of the tabs.
ref: https://developer.apple.com/documentation/uikit/uitabbarcontrollerdelegate
Related
I have run into an issue where setting the titleTextAttributes inside an individual ViewController. When the app is started, it creates a tableview that programmatically randomly generates colors for each list type. When the user clicks on a list, the color is sent to the DetailView controller which displays a sub list of items. I take the color and set the tintColor, as well as the titleTextAttributes to keep the theme consistent for both the list and navigation bar.
The problem lies when the user clicks the back button. When the back button is clicked, the previous View Controller's titleTextAttributes are now set to the color of the list that was just viewed. Nowhere in the parent View Controller am I setting the color of the title, which has me completely baffled. I have attached both screenshots as well as the code.
Thanks in advance!
Well, both the first and then the second (pushed) view controllers are in the same UINavigationController. Changing its state will affect its presentation in both of them (it is the same object).
I guess you will simply have to reset the attributes back in viewDidAppear of the root view controller.
I use UISearchViewController to control my app's search stuff. I saw there's a property called hidesNavigationBarDuringPresentation for handling the navigationBar's visibility, but what I wanna do is to hide tabbar during presentation, I can't find any properties to do this.
Any work-around?
You're right that there's no property for explicitly showing & hiding the tab bar, but it's easy enough to implement yourself:
Make your view controller (not the UISearchController) implement UISearchControllerDelegate.
Assign your view controller to the search controller's delegate property.
Implement willPresentSearchController() (or didPresentSearchController()) and presentSearchController() to hide your tab bar. (The former is called when the search bar is automatically shown; the latter is called when you show it manually.)
Implement willDismissSearchController() (or didDismissSearchController) to show it again.
Note that if your implementations simply toggle the search bar's hidden property, then the bar won't animate in and out; you'll have to do your own animation.
It may be a good idea for your implementations to check the value of hidesNavigationBarDuringPresentation so that your tab bar is shown and hidden only when the navigation bar is.
I would like to know if someone have an idea about how Tapbots made Tweetbot3 TabBar?
In my app, there will be many TabItems, and I don't want the "More" Tab (by default), but I'm very interested to have a similar system to Tweetbot, with a "picker" which opens on long press gesture on a TabBarItem.
But, I'm hesitating on the method. It's better to apply a customized UITabBar class, or to totally "deconstruct" the UITabBarController (to use a UIViewController and a custom "tabbar")?
Having created many custom tab bars, I'd start by subclassing UITabBar and UITabBarController. I wouldn't expect any roadblocks with this approach.
You may want to move the default buttons around and then add some custom buttons. Send a message back to the tab bar controller and let it display the popup choices view.
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.
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.