I have a side menu controller that is part of the rootViewControllerI never remove it from there and when it slides off screen - its just an animation that updates its frame details.
Is it possible to update this view, while it is not displayed on scene? I have a UiTableView in there and I would like to reload it while it is off screen - so when the user slides out the screen, its already populated with new content.
My first approach was a delegate - however, the delegate method doesn't get fired and I believe this is due to it being off screen. But, I somehow think side its in UIWindow it is never really deallocated like a normal view when it leaves the screen?
Edit
I am using this Github project for the menu.
The view I want to update is in a UINavigation controller, one level deep. I can get the current instance of it - however, the delegate method doesn't trigger.
It seems to me that you are going with something like this. Even if not, look at the example. Here RootViewController is always alive and you move one viewcontroller to parent view controller and remove other one.
I have two ways to fix it:
If you are removing first view from parent view controller. Don't remove it. So the controller is still live and use delegates to trigger the event.
Remove first view controller then use Root view controller to get the updates and once the previous view controller loads back take updates from root view controller and update this one.
Hope it can atleast give you an idea.
Related
I just came across a slide-in menu I really like: https://github.com/uzysjung/UzysSlideMenu
I would like to use this menu for an application that uses several view controllers (UIViewControllers and UINavigationControllers).
In Xcode, I created a single view application and made the view controller (MenuViewController) show the menu, like the creator did in his example project. I added more view controllers to the storyboard and connected them via segues to the MenuViewController. Upon selecting a menu item, these segues are triggered and the selected view is shown - so far so good.
But now, I run into the following problem:
All my view controllers are shown in full screen. That means that VCs that get segue'd in the viewport don't show the menu, because it's just not implemented there. I could put the menu in every VC, but that doesn't seem to be the right way to do it (even if I use some custom delegate method that every controller calls, like putMenuInViewController:(UIViewController *)target). I think I need something like a global singleton for the menu and make it appear in every view controller, but I have absolutely no idea on how to it or what to google for.
Any points into the right direction are greatly appreciated :)
I think you need to implement one root view controller with this menu as singleton, and add other view controller as child view controller to it.
I wrote a post about it, you can find it here:http://antrix1989.blogspot.com/2013/09/uiviewcontroller-as-singleton.html
I am pushing and popping from one view to the other within my App. The view is being retained in the memory so when you hit the "Back" button after pushing a view, the same screen that was before you pushed the view is retained.
For some reason, I will need to reload the parent view after popping from a child view. I need to display different content based on the actions the user taken when they were redirected to the child view.
I am using UINavigationController to navigate from one view to the other. I need it so I can easily go back and forth within the different views of the App.
The correct way to do this would be to perform your actions in viewDidAppear. Initialisation code that you write in viewDidLoad is called only once. But in viewDidAppear you can refresh your view's content every time the view is added to the window. The controller is retained in the memory for performance reasons. Removing it would hamper that factor.
Here is a stack overflow post that explains the different view* callbacks in good detail.
I am wondering what happens if a single instance of a UIView object gets added as a subview of multiple other views simultaneously.
If UIView:removeFromSubview: gets called then does it get removed from all superviews or just the currently displayed one?
For background:
I have a status-bar like view object that needs to be displayed within several different other views (each other view is managed by its own view controller).
[i.e. a) the user is in one view, b) something happens to make the status-bar-like view appear, c) the user switches to another view d)the status bar is still visible in the new view e) the status bar expires after a time and disappears from site. And so on]
Initially I implemented this by adding/removing it as required as a subview of the window, and this was managed by a singleton.
However due to some complications with some animations I have instead added it as a subview of each of the main view's for each of the view controllers.
Note that there are not multiple copies
When the view needs to be removed I am calling its removeFromSuperview:, and everything is all working perfectly.
However I am wondering what the situation is regarding the removal of the view, is it being fully removed or is there something else I need to do?
For example the view might get added to N view controller's views by calling addSubview as required (it will only get added to each view controller if that view controller actually launches)
However when it is being removed I am only calling removeFromSuperview: for the view of currently loaded view controller, not all view controllers it might have been added to.
Next time I navigate to one of these other view controllers it displays fine without the view being there, even though I didn't explicitly call removeFromSuperView.
As I said everything is working as it is, however at the back of my mind I feel there might be something missing?
Hope this was understandable.
You can only have it added to one view. Documentation is your friend!
(void)addSubview:(UIView *)view:
Views can have only one superview. If view already has a superview and that view is not the receiver, this method removes the previous superview before making the receiver its new superview.
From my point of view, having to add a same view to different parent views (and more important, from different view controllers) is an indication that something is wrong on the design...
However, if you really (really) need so, I had always thought that a view instance could have one and only one parent view... Moreover, you can access it by [myView superview] message, which gives you a UIView instance instead of an array... It may auto remove from its old parent before adding to a new superview?
About the design, what about creating it each time you need a new one and have a singleton to manage their status/logic?
Good luck with that!
I have a basic modal view system.
My app loads the UI base in which there are 2 buttons presenting 2 other views.
In those views, a dismiss button.
Everything works fine.
BUT, in one of the 2 modal views, I have a bunch of UISlider & UISwitch.
I want them to retain their values but the dismiss loses them: as soon as I trigger the button to show the view containing the UI elements, this view is shown with all values for all elements as I put initially in the xib.
should I store all values in variables, then in viewWillAppear I could "recall" them ?
would you advice me another strategy ?
Yes, your proposed approach is exactly the right sort of thing. But be careful; viewWillAppear can be called for many reasons; make sure you're only doing this when the view controller is coming into existence and showing the view for the first time.
NSUserDefaults can be an excellent place to store globally needed info like this. In viewWillDisappear, store the desired state info (values of the sliders and switches) in defaults. Then retrieve them the next time the view is about to appear.
When you create the modal view you are creating a new instance of the modalViewController an the modalView. This new instance knows nothing about any other instance. There are a few ways you can retain the information from previous iterations of these modal view controllers.
How I would do it:
Set up place holders in your main view and pass the values that the user selects back to the main view via a protocol and delegate setup. Then when you segue to the modal view you can load those variables in before displaying the modal view.
So let's say you have a dictionary with all of the values: {slider = YES, someValue=10,...} Create that dictionary in the main view controller, the first one that opens, and place some default values in it.
In your modal view controllers create the same dictionary as a property.
Create a protocol in your modal view controller with a method that is something like
- (void) doneEditing:(NSDictionary *)values
Set up your first view as the delegate for the modal view controller and in the implementation of doneEditing copy the values to the dictionary that is present in the first view before popping the modal view.
When the first view is ready to present the modal view again, copy the values to the dictionary property of the modal view before presenting it.
I hope this gets you headed in the right direction. It's important to remember that each time you segue or create and present a modal view you are creating a brand new instance of that view, it knows nothing about the previous instance at all unless you tell it something about it.
My app has 5 screens which are controlled by a tabbar at bottom, and one of them is a SplitView.
My Problem is:
The master view is just cause viewWillAppear only one time at first rotation.
The detail view is also just cause viewWillAppear only one time at first load.
While I would like viewViewAppear of both master and detail view are getting called each time this screen is opened, because there are 5 different screens, and user may leave this screen to view another, so I would like to know whenever master and details view appear to change layout or refresh data.
Please help me, thanks in advance!
It looks like you just anwsered your own question. I know its something you dont want to hear but apple's documentation says it must get the root view. Try to restructure your app a bit.
Link to documentation:
http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/iPadControllers/iPadControllers.html#//apple_ref/doc/uid/TP40007457-CH6-SW2
From the documentation:
A split view controller must always be
the root of any interface you create.
In other words, you must always
install the view from
aUISplitViewController object as the
root view of your application’s
window. The panes of your split-view
interface may then contain navigation
controllers, tab bar controllers, or
any other type of view controller you
need to implement your interface.