I want to be able to turn my UIPageViewController as a result of an event on a particular page. Using the Page View template in Xcode, what is the proper way to achieve this? I was thinking of just having DataViewController and ModelController contain a reference to the UIPageViewController in RootViewController and then use the [(UIPageViewController *) setViewControllers] method, but that seems sloppy. Is there a better way to do this?
The UIPageViewController is already accessible from the DataViewController. All UIViewController subclasses have a field called "parentViewController" that points at the UIViewController subclass that owns them (which a UIPageViewController uses).
If you want to change the page, just call
[((UIPageViewController*)self.parentViewController) setViewControllers:
target direction:UIPageViewControllerNavigationForward completion:nil];
Related
i've embed my first ViewController in an navigation controller. This auto generate an back button to all the ViewControllers.
The problem is that when i save a video into my core data it automatic go to a new ViewController, but then i'm able to go back to the ViewController where i added the video. Is there a way to like delete/reset the former ViewController that has presented and therefor control how far you can go back by clicking the back button?
Or what would be the best solution?
It's hard to offer advice without seeing your exact use case, but it sounds as though instead of pushing a viewController onto a navigation stack, you might want to do something like present a modal viewController.
Instead of doing pushViewController:animated, try [self presentViewController:newViewController animated:YES completion:nil]. If you're presenting your viewController via a segue in Interface Builder, change the segue type to 'modal'.
You'll also then need to add a button to dismiss your viewController - you can use the [self dismissViewController:animated:completion] method.
The structure of my MainStoryboard is:
->Tab Bar Controller -> Navigation Controller -> View Controller (Search)
The behaviour I want to have is that when the user re-selects the Search tab, the UIScrollView on it scrolls to the top. I am unsure how to get the event from the TabBarController, however.
I've been looking at a lot of stuff about UITabBarDelegate, particularly:
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
I have, not quite managed to get this to work properly though. I am very unsure about how to go about setting the delegate (assuming that is the way it's done). I've tried hooking it up in IB, but it wouldn't let me. I also tried to get the UITabBar from the AppDelegate (after looking at some seemingly-related answers).
Any pointers will be greatly appreciated (unless they're null).
UITabBar *aTabBar = [UITabBarItem alloc] init];
....Any other modifications you want to make to aTabBar....
[aTabBar setDelegate:self]
Don't forget to add "<UITabBarDelegate>" to the "#interface" part of whatever object you're trying to designate as the delegate.
For my own code, I usually use some object that isn't the application delegate (as the app delegate is usually meant for application level events like "application is suspending" or "application is coming back into foreground"). If you add "<UITabBarDelegate>" to your Search view controller, make sure that whatever you do with the "didSelectItem" method is applicable only to the Search view controller. Otherwise instantiate some different object if you want to do actions on various view controllers based on which tab bar item is being displayed.
So I have a viewControllerA, and I want to add another View managed by viewControllerB to it. There is only one UISlider activating a simple action in viewControllerB. It won't crash if I don't touch this UISlider, it will once I use UISlider. I am using ARC. I am using:
[self.view addSubView: viewControllerB.view];
to add viewControllerB to viewControllerA. Am I missing something? Thanks.
OK. It looks like a really simple situation. I just added one view controller and one action. Here is the demo project code on github: https://github.com/randomor/Demo
The reason why I want this to work is because I have another app that will create a view controller on the spot and add it to anther view. And I don't want to do it modally, because I don't want the new view controller to cover the whole screen. Thanks.
SOLUTION: So I'm now just using the latest ViewController containment API:
[self addChildViewController:viewControllerB];
It works! as long as I added this line, the event will be passed to its own controller and it stopped crashing.
i recommend you, to use the following code
in ViewControllerA.h
#import "ViewControllerB.h"
in ViewControllerA.m (where you want to push the new controller)
ViewControllerB *newController = [[ViewControllerB alloc]init];
[self presentModalViewController:newController animated:YES];
in ViewControllerB.m you will need
[self.presentingViewController dismissModalViewControllerAnimated:YES];
to make it vanish again.
concerning multiple controllers for one open screen (Apple ViewController Programming Guide):
Each custom view controller object you create is responsible for managing exactly
one screen’s worth of content. The one-to-one correspondence between a view controller
and a screen is a very important consideration in the design of your application.
You should not use multiple custom view controllers to manage different portions
of the same screen. Similarly, you should not use a single custom view controller
object to manage multiple screens worth of content.
You should try and avoid the practice of nesting UIViewControllers. While it is technically supported in iOS5, it is ill-advised, for many reasons, including the type of problem that you're having (you have a dangling pointer to a UIViewController, which is why you are crashing).
http://blog.carbonfive.com/2011/03/09/abusing-uiviewcontrollers/
Although this question is extremely vague, I imagine that you are not keeping a reference to View Controller B, and so when view B tries to interact with it, it causes EXC_BAD_ACCESS.
What's the object that is set as the target for the slider? If it's a EXC_BAD_ADDRESS, then you may not be retaining the target, most probably the view controller for the slider.
I need a custom button like Instragram has in profile tab (the buttons that shows the number of photos and followers) but i don't know how to start to implement it.
Do i need to subclass UIButton or is there other way easier?
I think, the easiest approach would be to create a UIButtom with the typeUIButtonTypeCustom and add a subview to it with imageviews and labels as subviews to create the UI. Composition over inheritance.
Subclassing UIButton seems to me to be the obvious solution. I agree that subclassing UIViewController makes no sense. You don't use UIViewController objects to manipulate individual subviews within a view hierarchy controlled by another UIViewController object.
There are plenty of ways to do this, personally I would subclass UIViewController. Then you can edit its .xib in interface builder to make it look however you want and set different values programmatically. Then to detect a tap on the button you can just use the touchesBegan and touchesEnded (I'm pretty sure those aren't complete method names, check in the docs for more info on them) methods. If you want you could also set up a UITapGestureRecognizer for the view instead.
View A has a button upon clicking it, we go to view B
View B does not retain a pointer to view A.
From view B, i'd like to load view A back (programmatically)
Effectively, i'd like to kill B and replace it with A.
I was thinking that the following should work but, it does not
Calling from View B
ViewController *main = [ViewController new];
[self addSubview:[main view]];
What am i missing please?
Personally I think the easiest way to do this would be by having a UIViewController with an IBOutlet to both UIView objects. You can add and design them both in the interface builder and just set one of them (view B) as hidden (it's a property in UIView).
Then, you could specify a button action to toggle the visibility of view B.
I must add though that there are constructs for implementing screen flows, such as the NavigationController. In your case, however, you might also consider the use of the presentModalViewController:animated: method.
It all depends really, but in general it's better practice to make a seperate UIViewController for each UIView in your application.
Hope this helps!
This sounds to me like you're looking for a navigation controller. You can easily take away a navigation controllers NavBar and take away the animations if you don't want them - but this would achieve exactly what you're looking for.