UIPageViewController Minimum Setup Template

The minimum setup to get started using the UIPageViewController.

 
class ViewController: UIPageViewController, UIPageViewControllerDataSource {

    var pages: [UIViewController] = [UIViewController]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        dataSource = self
        
        pages.append(UIStoryboard(name: "Main", bundle: nil)
            .instantiateViewController(withIdentifier: "Page1"))
        pages.append(UIStoryboard(name: "Main", bundle: nil)
            .instantiateViewController(withIdentifier: "Page2"))
        pages.append(UIStoryboard(name: "Main", bundle: nil)
            .instantiateViewController(withIdentifier: "Page3"))
        
        setViewControllers([pages.first!], direction: .forward, animated: true, 
            completion: nil)
    }

    func pageViewController(_ pageViewController: UIPageViewController, 
        viewControllerBefore viewController: UIViewController) -> UIViewController? {
        
        let index = pages.index(of: viewController)!
        
        if index == 0 {
            return nil
        }
        
        return pages[index - 1]
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, 
        viewControllerAfter viewController: UIViewController) -> UIViewController? {
        
        let index = pages.index(of: viewController)!
        
        if index == pages.count - 1 {
            return nil
        }
        
        return pages[index + 1]
    }
    
    func presentationCount(for pageViewController: UIPageViewController) -> Int {
        return pages.count
    }
    
    func presentationIndex(for pageViewController: UIPageViewController) -> Int {
        return 0
    }
}
 

(Xcode 8, Swift 3.0)

Layout Anchors

Why describe what layout anchors are when you can show it!
These are the two UIViews I will be demonstrating.

Technically this example is not using a Layout Anchor but it is a good way to center objects.

 
myView.center = view.center
 

IMPORTANT! All examples below will need to include these 3 lines of code for them to work.

 
myView.translatesAutoresizingMaskIntoConstraints = false
myView.widthAnchor.constraint(equalToConstant: 125).isActive = true
myView.heightAnchor.constraint(equalToConstant: 125).isActive = true
 

Without setting translatesAutoresizingMaskIntoConstraints to false, the new constraints will do nothing.
Without a height and width I found a UIView will just collapse into no height or width.

Horizontal Examples

 
myView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
myView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
 

 
myView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
 

 
myView.rightAnchor.constraint(equalTo: view.leftAnchor, constant: 30).isActive = true
 

 
// Offset from center -50
myView.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: -50).isActive = true
 

Vertical Examples

 
// Going to center myView for the Vertical examples.
myView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
myView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
 

 
myView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
 

(Xcode 8, Swift 3.0)

Getting Height or Width of Text

You use UIView.sizeThatFits to get the best size to fit a given size.

• To get width, fix the height and maximize the width of your given size.
• To get height, fix the width and maximize the height of your given size.

Code Example of Getting Width of Text

 
@IBOutlet weak var sampleTextLabel: UILabel!

@IBOutlet weak var widthTextField: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    
    // Fix the height to get the width.
    let suggestedSize = CGSize(width: CGFloat.greatestFiniteMagnitude, 
                               height: sampleTextLabel.frame.height)
    widthTextField.text = sampleTextLabel.sizeThatFits(suggestedSize).width.description
}
 

Note: CGFloat.greatestFiniteMagnitude gives you the maximum number for a float.

(Xcode 8, Swift 3.0)

Animation With Spring (Bounce)

Code Example

 
 
UIView.animate(withDuration: 0.2, 
    delay: 0, 
    usingSpringWithDamping: 0.5, 
    initialSpringVelocity: 0.5, 
    options: .curveEaseOut, 
    animations: {
    // Your animation
}, completion: nil)
 

Parameters

• withDuration - How long the animation should last
• delay - How long to wait until starting the animation
• usingSpringWithDamping - Applies damping to the spring (bounce). Using 1 will completely damp out the spring so the animation just slides into place and stops. Lower the damping for more bounce (example: 0.1 - 0.9).
• initialSpringVelocity - How fast you want the initial animation to happen. Using 1 will start it fast, 0 is normal. Apple says, "You'll typically want to pass 0 for the velocity."
• options:
  • curveEaseInOut - Start slow, speed up, then slow down
  • curveEaseIn - ("In" specifies the start of the animation) Start slow, speed up, then suddenly stop
  • curveEaseOut - ("Out" specifies the end of the animation) start fast, then slow down until stop
  • curveLinear - Constant speed throughout animation

(Xcode 8, Swift 3.0)

Menus in Your Apps

In these videos I show you two options for creating menus that slide out from the side. The main thing I'm doing is using a UIView and animating the movement to show a menu.