I am new to programming and swift.
I have a mainViewController with a containerView which contains a scrollView. I would like to be able to pass the value of the y contentOffset from this scrollView ( from the scrollViewDidScroll(scrollView function) to update the frame.origin.y of a image in the mainViewController so that it moves inrelation to the containerView's scrollView.
How can i share data between the two View controllers (or multiple view controllers) using swift?
Any help would be greatly appreciated!!!
Suppose your scroll view is named sView and UIImageView is named img.
Then you should write something like this in your ViewController:
In class declaration add comma and scroll view delegate
class ViewController: UIViewController, UIScrollViewDelegate {
Then you should implement scrollViewDidScroll function somewhere after viewDidLoad
func scrollViewDidScroll(scrollView:UIScrollView){
if scrollView == sView {
let frame = CGRectMake(img.frame.origin.x, sView.contentOffset.y, img.frame.size.width, img.frame.size.height)
img.frame = frame
println("Just check if it's called")
}}
After that add to viewDidLoad
//You've aldeady declared sView and img
self.view.addSubview(sView)
self.sView.delegate = self
Should work then :)
Related
I'm trying to add a subview below my UISegmentedControl from an extension so when I add more properties to this subview it can be reused from other UISegmentedControls within the app.
It appears in the right place, but for some reason sometimes appears above some segments and sometimes below. Am I missing something?
So far in my extension, that's what I have:
import UIKit
extension UISegmentedControl {
func addBackgroundView() {
let backgroundView = UIView();
backgroundView.frame = self.bounds;
backgroundView.backgroundColor = UIColor.purple;
self.insertSubview(backgroundView, belowSubview: self);
}
}
And then, I call the extensions function from the viewDidLoad method in the ViewController:
self.segmentedControlUnit.addBackgroundView();
I dont think you can do this. this is the UI Hierarchy when i select 2nd segment ,
and this is the UI Hierarchy when i select 3rd segment
so the segment position changes depending on what segment you select.
Try to insert backgroundView at index 0 to make sure it below all of subview
self.insertSubview(backgroundView, at: 0)
I have a UIStackView and I am dynamically adding UIViewControllers contained, here is my code;
[self addChildViewController:driverForm];
[self addChildViewController:marketingView];
[self.stackView insertArrangedSubview:driverForm.view atIndex:0];
[self.stackView insertArrangedSubview:marketingView.view atIndex:1];
[driverForm didMoveToParentViewController:self];
[marketingView didMoveToParentViewController:self];
After reading the documents it states I must call didMoveToParentViewController.
The problem I am facing is, the actions on the final UIViewController are not being called, but the first ViewController does. If I swap these round the first one works and the last one does not.
Simply add the view of your ViewController to your UIStackView like this:
yourStackView.addArrangedSubview(yourViewController.view)
Also, you don't need to be worried about the view being nil as it always returns UIView!
Note that the order is reversed, so the last appears first. To address this, assuming you have an array of view controllers, you can use stride to traverse your array inversely and add view controllers to your stack.
Here is a quick copy/pasta version for Swift 5:
private var childViewController: UIViewController
private var stackView: UIStackView?
// MARK: - UIViewController
override func loadView() {
super.loadView()
// 1. Add the child view controller to the parent.
addChild(childViewController)
// 2 Create and add the stack view containing child view controller's view.
stackView = UIStackView(arrangedSubviews: [childViewController.view])
stackView!.axis = .vertical
self.view.addSubview(stackView!)
// 3. Let the child know that it's been added!
childViewController.didMove(toParent: self)
}
UIStackView is for arranging multiple subviews in the same UIViewController class. how can you use it for different UIViewControllers?
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIStackView_Class_Reference/#//apple_ref/doc/uid/TP40015256-CH1-SW31
I am trying to use a UIScrollView to show a series of UIViews. In my storyboard I have a View Controller containing a UIView that is constrained using AutoLayout.
View Controller (UIView in grey)
In order to call the UIScrollView I am using the following method:
func initScrollview() {
self.mainScrollView = UIScrollView(frame: self.mainView.bounds)
self.mainScrollView!.contentSize = CGSizeMake((self.mainView.bounds.width)*CGFloat(3), self.mainView.frame.height)
self.mainScrollView!.backgroundColor = UIColor.greenColor() // For visualization of the UIScrollView
self.mainScrollView!.pagingEnabled = true
self.mainScrollView!.maximumZoomScale = 1.0
self.mainScrollView!.minimumZoomScale = 1.0
self.mainScrollView!.bounces = false
self.mainScrollView!.showsHorizontalScrollIndicator = true;
self.mainScrollView!.showsVerticalScrollIndicator = false;
self.mainScrollView!.delegate = self
for i in 0...3 {
var tempView = SubView(frame: self.mainView.bounds)
pages.insert(tempView, atIndex: i)
self.mainScrollView!.addSubview(pages[i]);
}
self.mainScrollView!.scrollRectToVisible(CGRectMake(mainScrollView!.frame.size.width, 0, mainScrollView!.frame.size.width, mainScrollView!.frame.size.height), animated: false)
}
When I run my code, the UIScrollView does not fit the UIView. Instead it is too short and too wide. The result looks like this:
UIView in grey, UIScrollView in green
What am I doing wrong that is causing the UIScrollView to be incorrectly sized?
You should put the codes that you init the UI element sizes base on the screen size(UIView of UIViewController) in viewDidLayoutSubviews. Because in viewDidLoad, the screen didn't adjust its size yet,
In the above code, there no mention of adding the mainScrollView to the mainVew.
To whose view are you adding the mainScrollView? My opinion would be you are trying to add it to self.view whereas it should be to self.mainView
After the initScrollView() function is called try adding it the below code
self.mainView.addSubview(mainScrollView!)
This would probably be easier if you had placed all these views directly in your storyboard instead of programatically. I don't see anything in your code that can't be done visually in IB. Also, if you have autoLayout active in your storyboard, setting frames and sizes in code won't work. (auto-layout will change your values on the next pass)
I'm trying to add a sliding photo gallery functionality to the top portion of a view.
To give context, a user taps on a button or row or something. Then i load a scrollview with a uistackview in it. organized vertically, i had an image, and then another stack view with some text in it. Now, i want that image to become part of a larger "gallery". My research told me to implement UIPageviewcontroller and add the other images to a childVC.
i used this as a tutorial (the first example): http://www.raywenderlich.com/76436/use-uiscrollview-scroll-zoom-content-swift
the only relevant deviation from the tutorial my app has is that it creates things programmatically.
With my proof of concept for the gallery functionality, i wanted to integrate it with the previously mentioned stack view. my plan was to first add the pageviewcontroller stuff into the overall stack view with the original image view right below it and then simply remove the original image view to leave me the final product.
i was able to add the pageviewcontroller.view to the stackview, but the gallery doesn't show. taking a look at the UI Inspector, i can see that the gallery is kinda loaded, but it's messed up.
it's as if the uiview has a frame of 0 height and so the other stack view items don't respect the images that the pageviewcontroller is trying to show.
I think it could be that stack views can only handle specific views, not stuff as complicated as pageviewcontrollers.
also note: my implementation is all programmatic, no storyboards, and so for no xibs. so maybe i missed something here.
here is some code, if it helps:
note the constrain functions you see are from the "cartography" pod
this adds the "gallery" to the stack view, it's a delegate function from my view
func addZoomStuff(sender: UIStackView) {
let zoomer = PageBaseViewController()
addChildViewController(zoomer)
zoomer.view.translatesAutoresizingMaskIntoConstraints = false
zoomer.view.tag = 5
sender.addArrangedSubview(zoomer.view)
zoomer.didMoveToParentViewController(self)
}
this is what creates the scrollview, image view, etc for the gallery items:
override func viewDidLoad() {
super.viewDidLoad()
//MARK: - Zoom View Elements
// prep
scrollView = UIScrollView(frame: self.view.frame)
scrollView.delegate = self
self.view.addSubview(scrollView)
constrain(scrollView, view) { view, view2 in
view.edges == view2.edges
}
self.view.setNeedsUpdateConstraints()
// 1
let image = UIImage(named: imageName)!
imageView = UIImageView(image: image)
// 2
scrollView.addSubview(imageView)
constrain(imageView){ view in
view.edges == view.superview!.edges
}
scrollView.contentSize = image.size
i tried adding the constraints like this but there was no effect
func addZoomStuff(sender: UIStackView) {
let zoomer = PageBaseViewController()
addChildViewController(zoomer)
view.addSubview(zoomer.view)
constrain(zoomer.view, view) { view, view2 in
view.width == view2.width
view.height == view2.height * 2 / 3
view.leading == view2.leading
view.top == view2.top
}
zoomer.view.setNeedsUpdateConstraints()
zoomer.view.removeFromSuperview()
zoomer.view.translatesAutoresizingMaskIntoConstraints = false
zoomer.view.tag = 5
print("sender.subviews: \(sender.subviews)")
sender.addArrangedSubview(zoomer.view)
zoomer.didMoveToParentViewController(self)
print("sender.subviews: \(sender.subviews)")
}
if this method isn't going to work, can i do a nested horizontal stack view instead of the pageviewcontroller and somehow get that same scrolling/snap effect to see on image view at a time?
TLDR;
Create a subclass of UIPageViewController, make it it's own delegate.
Initialize the subclass with a plain UIViewController, only set a backgroundcolor.
In the pageviewcontroller subclass, implement the two delegate callbacks for a next and previous viewcontroller: create a plain viewcontrolller, with some random backgroundcolor.
If this works, replace the plain viewcontroller by your actual contentviewcontroller.
Long version:
Have you seen this: Maybe this link will help: https://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/PageViewControllers.html
It might help, as it explains the details of UIPageViewController. Basically, you need to create a viewController (not a view!), that shows one page of the gallery. So this VC has a stackview, and manages the content of it. The pageviewcontroller is initialized with your first contentviewController. If you create a subclass of the uipageviewcontroller, you can set self of that subclass as the delegate of it. Implement the delegate callbacks that return the next or previous viewController and thats it. For this last part, it is convenient to have a property on the contentviewcontroller from which the subclasses of the pageviewcontroller can figure out what data to set on the next or previousviewcontroller.
Your title seeks to hint at some confusion: its not possible to add a viewcontroller to a view. You can only add other views to a (stack)view. A viewcontroller owns and manages a viewhierarchy. A pageviewcontroller has no content, but manages the insertion and removal of viewcontrollers. as the pageviewcontroller is a containerviewcontroller, it will als take the contentViewcontrollers' views and place them in the viewhierarchy. But this is not something your code has to do when you subclass UIPageViewControlller and implement it's delegates on itself (and don't forget to assign self to be the delegate).
I have a UIScrollView that contains a bunch of view controllers, and in each view controller there is a button that if pressed, should scroll the UIScrollView to a certain position. How do I go about connecting the viewController IBAction for the button to set the scroll position of the UIScrollView?
I know I'll call contentOffset at some point, but I'm struggling with getting the ViewControllers to control the Scroll View.
One way you could do it... When you add each UIViewController.view to the UIScrollView you could also set a var in each UIViewController that references the UIScrollView.
For example, for some UIViewController, we'll call it X, put
var scrollView: UIScrollView?
in it. Then in your class that controls the UIScrollView, when you add view X to the UIScrollView, also do the following:
viewControllerX.scrollView = self.theScrollView
Now, when your IBAction method is called in viewControllerX, you have a reference to the UIScrollView and as you said, can do self.scrollView.contentOffset.y = someValueHere to change its position.