I have a UIViewController which i have embedded in a Navigation controller using:
Editor->Embed In->Navigation Controller
Now i want to get the upper bar height for some calculations but i cant ctrl+drag
anything to use the needed property.
How can this be done?
The "upper bar" is the UINavigationController's navigationBar. And thus your view controller has a reference to it.
If you are trying to do auto layout, stay inside the embedded view controller and pin to the Top Layout Guide. That is what it is for.
Related
I have a view controller with a table view and a tab bar controller. I perform a segue when one of the cells is tapped in the didSelectRow method. I then pass the data in prepareForSegue. The segue is set up in the storyboard from the view controller to the tab bar and its kind is "Show".
When the tab bar controller is displayed (well, one of its view controllers), the content is at the very top of the view. The problem is fixed after I switch tab bars and then go back to the original tab bar. Any way to fix this?
Are you using interface builder?
Open storyboard where you defined this view controller.
Then in Attributes Inspector DESELECT the Extend Edges Under Top Bars property.
Alternatively you can make your view snap to the Top Layout Guide instead of the root view itself.
Back when I first created the foundational layout for the app I'm currently working on in Storyboard, I did it in two steps:
Selected my View Controller and used Editor->Embed In->Navigation Controller.
Selected my View Controller again and used Editor->Embed In->Tab Bar Controller.
This was the resulting layout:
Question 1: Why do these steps create such an odd layout?
In this weird layout that seems to imply that the Navigation Controller is attached to the Tab Bar Controller as its parent, the only way I can get navigation items to display in the app (in the view controlled by the View Controller on the right) is by placing them in the nav bar of the Tab Bar Controller scene.
However, this creates various issues, including not being able to create an IBOutlet in my View Controller file for a custom view I drag into the title view slot in the Tab Bar Controller scene. Meanwhile, dragging anything into the navigation bar in the View Controller scene just makes it not appear in the app when it runs.
Question 2: How can I fix this layout so that I can control-drag from navigation items into my View Controller file? Or is everything actually correct, and I'm just trying to force something I shouldn't? (My intention here is to be able to set the custom title view's text in my View Controller code.)
Its obvious, if you want to embed MyViewController to NavigationController then you need to change your second step and need to embed NavigationController to Tab Bar Controller.
Selected MyViewController and used Editor->Embed In->Navigation Controller.
Selected NavigationController Embed with MyViewController and used Editor->Embed In->Tab Bar Controller.
It should look like this.
Note: You need to embed MyViewController to navigationController only if you want to perform push operation on this TabBarItem means with MyViewController other wise simply embed MyViewController to TabBarController no need to embed it with NavigationController.
I was going through Apple's documentation about navigation controller and find this point ambiguous and hard to comprehend.
It was written in this online documentation of navigation controller.
Navigation Controller Views
A navigation controller is a container view controller—that is, it
embeds the content of other view controllers inside of itself. You
access a navigation controller’s view from its view property. This
view incorporates the navigation bar, an optional toolbar, and the
content view corresponding to the topmost view controller. Figure 2
shows how these views are assembled to present the overall navigation
interface. (In this figure, the navigation interface is further
embedded inside a tab bar interface.) Although the content of the
navigation bar and toolbar views changes, the views themselves do not.
The only view that actually changes is the custom content view
provided by the topmost view controller on the navigation stack.
From that, my understanding is that inside this "view" property. There should be at least two subview inside this view.One is the navigationBar the other is the contentView of the current displayed viewController’s view. But while I am debugging only the navigation bar showed with another view called UINavigationTransitionView showed.
My question is, is this normal. Have I done anything wrong?
Second, what is the most common way to access current displayed viewController's view with only the reference to the navigation controller.
Thanks
UINavigationTransitionView controller contains one wrapper view which intern will have the current uiviewcontroller's view.
You can probably find this view as a subview of UINavigationTransitionView. However this is not the "right" way to do this. The proper way is to go through property "topViewController" and then take its view:
self.navigationController.topViewController.view
If there is another view controller or its view that you need, you have access to whole view controller's hierarchy across navigation controller through viewControllers property.
self.navigationController.viewControllers
More here:
https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UINavigationController_Class/index.html
In my app, I have a collection view controller that is accessible by a modal type segue. What I am want is to have a top bar on the collection view controller. However, when I set a top bar in attributes tab of the collection view controller, it shows on the storyboard but not in simulator?
I think that What you are looking for is a UICollectionReusableView.
You should use UINavigationController.
If you're not using it, you could also add a UIToolbar.
That Storyboard section only sets the appearance in case you're using UINavigationController.
In my app, i have a main view controller which sometimes brings a modal view on top of it. This modal view is a UINavigationController with a navigation bar. I want to display an image above the navigation bar, and have the navigation bar appear below the image.
I do not want to subclass anything and the app uses autolayout, i do not want a bunch of delegate callbacks and frame calculations. The view inside the navigation controller (the actual modal content) must still respond to different screen sizes correctly, such as rotation, call status bar etc. Also, no IB solutions please, these views are all managed in code.
How do i accomplish this?
I would turn off AutoLayout and place the image at the top
I don't think you can do it with your modal view being a navigation controller. I would do it by making that modal controller a UIViewController that you set up as a custom container controller. You can add an image view to the top of this controller's view and add the view of a child view controller (which would be a navigation controller) to the bottom. This would be a lot easier to do in a storyboard using container views, but it certainly can be done in code.