OK. I haven't actually seen how to do this anywhere. It may be a question of "You can't get there from here." or "Holy ##$! That is such a disgusting hack it should be taken behind the woodshed and shot!".
I have a tabbed Swift 3 iOS app that will dynamically update the Tab Bar images of selected pages as the page state changes.
I do that sort of like this:
if let navController = self.navigationController as? MyNavController {
navController.tabBarItem.image = navController.tabBarImage
navController.tabBarItem.selectedImage = navController.tabBarImage
}
The tabBarImage is actually a calculated property. This snippet is called within a UI callback that updates when the state changes.
This works great.
When in the MoreViewController, though, not so great. Those images remain stubbornly static, no matter what I do.
I have done some exploration of the MoreViewController. I can get at the tableView and the cells, but that smells like the kind of hack that will get my app taken behind the woodshed by the Blue Meanies at App Review.
Is there a proper way to do this?
You can use Notification and pass the images within a Dictionary as a Notification object. Then you can get different tabBarImage with different key value at once.
OK. I figured out how to do it.
I was crawling back along the navigation controller path; which worked fine for items not in the more space.
I fixed it by crawling forward from the tab bar controller, instead:
self.tabBarController?.viewControllers?[MySelectionIndex].tabBarItem.image = self.tabBarImage
self.tabBarController?.viewControllers?[MySelectionIndex].tabBarItem.selectedImage = self.tabBarImage
Related
I have read the apple guidelines and I know it says you shouldn't do that but hear me out as I would like to know if what I am doing is bad practice.
When my application loads up, in the app delegate, a web call is made which sets up the order of the tabs, as well the content within it. Web call is like this
WebCalls *wc = [[WebCalls alloc] init];
[wc setWebCallDidFinish:^(NSString * json) {
// set up tab order here, as well as stores the JSON in a file on the phone
// Also code here to download images and cache them on phone
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
}
[wc getData:phoneNumber];
Now this code works great but the problem is what will happen when app starts is
Launch image shows for a second (which is not very long, sometimes it's half a second or less so just annoying)
Screen goes black for about 2 seconds while json is parsed and images downloaded etc
Then first tab controller is shown
What I want is a seamless transition between the splash screen and the first screen so the user never sees black screen.
What I was thinking of doing is something like this
Change iPhone splash screen time
In the answer given, the guy pushes a view forward to be the splash screen. Would it be bad practice to push that view forward, and then in that screen do the web calls which gets json data, and downloads images, then dismiss the view and have the tabcontroller view become main view?
Or how else would I prevent this delay? Is it bad practice to have a large enough web call like this in AppDelegate?
If this is bad practice to push a view forward while doing background loading, what else would you recommend? Would it be better if I just make the tabController the main rootViewController first and do the webCall in the first tab shown instead, then update the tabs when this web call finished? I was considering this one, but the tab order could be in any order after the web call is made, so not sure what tab will be shown first.
Would be grateful for your input
In the answer given, the guy pushes a view forward to be the splash screen. Would it be bad practice to push that view forward, and then in that screen do the web calls which gets json data, and downloads images, then dismiss the view and have the tabcontroller view become main view?
This is the way to do it. It's generally bad practice to download stuff from applicationDidFinishLaunching, what happens if the phone is not connected to the internet?
Present a simple view controller (using presentModalViewController:controller animated:NO with a UIActivityIndicator and a label describing what's going on, and then dismiss it when loading finishes (or it it fails, just display an error and deny access to the app). Remember to also check for airplane mode and notify the user.
I have a TabBar Application with 2 tabs saving/fetching data to and from CoreData. The problem that I am having is that when the form has been filled and the user has touched the save button the view is not re-loaded or re-initialised. All I want is for the view to be ready for the user to repeat the process with the next set of information. I am probably not thinking about this in the correct way so a pointer in the right direction would be very much appreciated...
Do I need to manually set everything including the managedObjectContext etc. to nil? Or is there something that I can do with methods like viewWillDisappear that will elegantly help me to "re-initialise" that specific tab?
I ave read up the Apple docs on view hierarchies, and life cycles but I just seem to have confused myself...
Thanks in advance for any suggestions, referrals to code or even recommendations on relevant reading material.
It sounds like what you want to do is reload any data to their default states when the user taps a button. Unfortunately, you'll have to do this manually, setting each IBOutlet's value to a meaningful default (probably the empty string).
There are two ways I can think of that would help make this more elegant:
Use an IBOutletCollection and fast enumeration to loop over all the IBOutlets and not have a bunch of code to do each one individually.
If you're switching tabs in between these events, you can something neat and use your app delegate as your UITabBarControllerDelegate for the tabBarController:didSelectViewController: to call the clearing-out method for you instead of relying on viewDidAppear.
I have a problem that I have not seen addressed in this particular way before, so hopefully someone can help me with it. Let's say I have a tab bar app with four views, one on each tab. Obviously the app will be forced to launch with the view controller it is told to launch with, but after that, it's up to the user to select which tab (view) to load next.
The problem comes from the fact that I would like to show a view on each tab ONLY the first time that particular view is loaded. Normally, you'd do this:
BOOL foo = [[NSUserDefaults standardUserDefaults]boolForKey:#"previouslyLaunched"];
if (!foo)
{
NSLog(#"FirstLaunch");
[[NSUserDefaults standardUserDefaults]setBool:YES forKey:#"previouslyLaunched"];
///Do first run view initializaton here////
}
However, doing that once sets the NSUserDefault for all of the app, meaning that only the view for tab 1 will show and not the other three. So, my question is, how do I show a view for each of my four tabs only the first time each view loads? This is a complicated question because the user is able to select any tab in any order, so I can't guide them down a path, I think.
Would I have to use a different key for each view? Would that work? It seems like that might be the best course of action here, but this is my first time working with NSUserDefaults, so I'm a little lost.
Any and all help is much appreciated!
Use a different key for each view:
e.g. viewController1PreviouslyLaunched, viewController2PreviouslyLaunched... etc
I have a nice little app on the app store that does pretty well for itself. Life was great until iOS 5 came to town. Now, I have a number of issues with my app that I have no way of fixing because I have no clue what is going on, because I feel that they are iOS 5 issues, not mine.
Was there an iOS 5 conversion manual I missed? Or did they just change everything for fun, and want us to figure out where all the easter eggs were?
Here is another issue I am experiencing (that I have wasted so much time trying to fix), that DON'T EXIST AT ALL when I simply say that I want to run the app in good ol' 4.2:
Modal view
My app is a simple reader app. I have a book reading view that displays text with a UIWebView. One of the features I have been working on involves the ability to take notes as you read. This is achieved by hitting a button, and presenting a modal view. Yes, a modal view. The most simple pre- iOS 5 thing you could possibly do. Now, when I dismiss my modal view, just by hitting cancel, and simply dismiss the view, when I get back to my reader view, the navigation bar at the top is pushed up half way off the screen! This doesn't happen in 4.2, but there it is in iOS 5!
What can I do to get this issue resolved?
Thanks for your help.
Ok, I was just able to figure out what in the blazes was going on. I had the shouldAutorotateToInterfaceOrientation value set to a BOOL variable, so that when the modalView was coming back, it didn't know the state/size of the status bar. Fixed that, and the problem disappeared.
I have the feeling it has something to do with the way you present and dismissing the modalview. Apple introduced a new method to present views. May you try using theses instead of the old ones and see if it fixes your problem.
So here is what you do:
change this method:
presentModalViewController:animated:
into the new preferred method introduced with iOS 5:
presentViewController:animated:completion:
Depending if you are using dismissModalViewControllerAnimated:to dismiss your view, change it into dismissViewControllerAnimated:completion.
This methods also have completion handler which is very useful to do some extra work after the view has been presented/dismissed. Maybe that also helps with your other issue. Let me know if that might helped.
A major change in iOS 5 is that the navigationController property of UIViewController is no longer set for modal views. Instead, there is a new (not present in iOS 4) parentViewController property. So where you're using navigationController in a modal view you need to change the logic to something like:
UIViewController* parent;
if ([self respondsToSelector:#selector(parentViewController)]) {
parent = self.parentViewController;
}
else {
parent = self.navigationController;
}
(That's from memory, so I can't guarantee that every t is dotted and every i crossed.)
I was seeing this same clipping problem.
I found out that the reason for my issue was that I set the content size within the modal dialog (something I did for my iPad layout), so removing these two lines seemed to fix the issue:
CGSize size = CGSizeMake(320, 480);
self.contentSizeForViewInPopover = size;
I thought the problem was fixed but it wasn't. After reviewing the code some more, cleaning the build, and retesting it turned out to be a shouldAutorotateToInterfaceOrientation which would return NO for all orientations, for a brief amount of time (flag == NO) while the app is loading (root controller). You want to at least return YES to one orientation like so:
- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
return !self.flag ? UIInterfaceOrientationPortrait == toInterfaceOrientation : YES;
}
I should know this by now, but I am still a bit confused. When my app navigates from one view controller to the next (via the navigation controller) I want to "finalize" the data for the current VC before going to the next VC. The only way I see to intercept the "page swap" is in the [old view viewWillDisappear] -> [newView viewWillAppear] transition. It seems weird, though I guess it works okay.
Is that really the right way to handle navigation transitions? My app is a bunch of VCs which collectively build a database file. Each VC deals with a different aspect of the data.
I don't know your exact setup, so this may not be useful to you, but I have good experiences with saving data in -(void)textFieldDidEndEditing:(UITextField*)tf, using tf.tag to index the fields. From there I commit the data to a storage class, and have no worries about what happens in the UI.
What exactly is involved in the "finalizing" part? I assume you are storing some state in the view controller for various fields and then you want to write that to the database file before going on to the next view?
When it comes to "edit view controllers" I find a nice way to do it is to have the view controller directly write to a simple model object which is injected through a property before pushing it to the nav controller.
So something like:
/* Somewhere in the app delegate, like application:didFinishLaunching */
DatabaseFileModel *model = ...;
viewController1.model = model;
viewController2.model = model;
/* ... */
[self.window makeKeyAndVisible];
Then each view controller writes to this model by setting properties etc. when a text field ends editing or whatever. Having the view controller write straight to the object means you don't need to handle viewWillDisappear etc.
If you do still need to do this however you can add a delegate to the navigation controller and handle these two methods:
– navigationController:willShowViewController:animated:
– navigationController:didShowViewController:animated:
See the UINavigationControllerDelegate documentation for more information.
This will let you keep the logic in one place rather than spread out in each view controller.