subclass of a generic UIViewController subclass isn't available in InterfaceBuilder [duplicate] - ios

Question

This question already has answers here:
Xcode 7 Swift 2 impossible to instantiate UIViewController subclass of generic UITableViewController
(2 answers)
Closed 6 years ago.
I have a generic UIViewController subclass that expects a type that is a subclass of UIView and also implements a specific protocol. I have a subclass of that generic UIViewController subclass. I have a view controller in a story board with it's type set to MyKeyboardAwareScrollViewController (the subclass of the generic UIViewController subclass). When I run my program I get a message:
Unknown class _TtC19ExploreCodeCoverage35MyKeyboardAwareScrollViewController in Interface Builder file.
Any ideas why/how to fix?
A protocol:
protocol MyProtocol{
func widgets() -> Void
func activeView() -> UIView?
}
A Generic View Controller Subclass (that requires a type that is a UIView implementing the protocol MyProtocol):
class KeyboardAwareScrollViewController<T:UIView where T:MyProtocol>: UIViewController {
private let titleView: UIView
private let contentView: T
private weak var scrollView: UIScrollView?
private weak var titleViewContainer: UIView?
init(titleView:UIView, contentView: T){
self.titleView = titleView
self.contentView = contentView
super.init(nibName: nil, bundle: nil)
}
required init?(coder aDecoder: NSCoder) {
self.titleView = aDecoder.decodeObjectOfClass(UIView.self, forKey: "titleView")!
self.contentView = aDecoder.decodeObjectOfClass(T.self, forKey: "contentView")!
super.init(coder: aDecoder)
}
override func viewWillAppear(animated: Bool) {
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardShown:", name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardHidden:", name: UIKeyboardWillHideNotification, object: nil)
}
override func viewWillDisappear(animated: Bool) {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func keyboardShown(notification: NSNotification){
let kbSize = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()
if let scrollView = scrollView{
let insets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: kbSize.height, right: 0.0)
scrollView.contentInset = insets
scrollView.scrollIndicatorInsets = insets
if let activeField = self.contentView.activeView(){
let convertedFrame = scrollView.convertRect(activeField.superview!.bounds, fromView: activeField.superview!)
let offsetFrame = CGRectOffset(convertedFrame, 0.0, 19.0)
let frame = CGRectInset(offsetFrame, 0.0, 17.0)
scrollView.scrollRectToVisible(frame, animated: false)
}
}
}
func keyboardHidden(notification: NSNotification){
if let scrollView = scrollView{
let insets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0)
scrollView.contentInset = insets
scrollView.scrollIndicatorInsets = insets
}
}
override func loadView() {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = UIColor.brownColor()
let sv = UIScrollView()
sv.backgroundColor = UIColor.clearColor()
sv.opaque = false
sv.translatesAutoresizingMaskIntoConstraints = false
sv.alwaysBounceVertical = true
self.scrollView = sv
let titleContainer = buildTitleContainer(self.titleView)
view.addSubview(titleContainer)
view.addSubview(sv)
//peg scroll view to container.
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[scrollView]|", options:NSLayoutFormatOptions(rawValue: 0), metrics:nil, views: ["scrollView":sv]))
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[scrollView]|", options:NSLayoutFormatOptions(rawValue: 0), metrics:nil, views: ["scrollView":sv]))
let contentViewWrapper = UIView()
contentViewWrapper.translatesAutoresizingMaskIntoConstraints = false
contentViewWrapper.addSubview(self.contentView)
contentViewWrapper.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|->=0-[contentView]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["contentView": contentView]))
contentViewWrapper.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[contentView]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["contentView": contentView]))
sv.addSubview(contentViewWrapper)
let viewsDictionary = [
"scrollView": sv,
"view": view,
"contentViewWrapper": contentViewWrapper
]
//peg contentView to be at least as tall as view.
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[contentViewWrapper(>=view)]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: viewsDictionary))
//peg contentView to be equal to host view width
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[contentViewWrapper(==view)]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: viewsDictionary))
//peg title container to width of container.
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[titleContainer]|",
options:NSLayoutFormatOptions(rawValue: 0),
metrics: nil,
views: ["titleContainer":titleContainer]))
//title view height.
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[titleContainer][contentView]",
options:NSLayoutFormatOptions(rawValue: 0),
metrics: nil,
views: ["titleContainer":titleContainer, "contentView":self.contentView]))
self.view = view
self.titleViewContainer = titleContainer
}
func buildTitleContainer(titleView:UIView) -> UIView{
let titleContainer = UIView()
titleContainer.translatesAutoresizingMaskIntoConstraints = false
titleContainer.backgroundColor = UIColor.orangeColor()
titleContainer.addSubview(titleView)
titleContainer.setContentCompressionResistancePriority(1000.0, forAxis: .Vertical)
titleContainer.addConstraint(NSLayoutConstraint(item: titleView, attribute: .CenterY, relatedBy: .Equal, toItem: titleContainer, attribute: .CenterY, multiplier: 1.0, constant: 0.0))
titleContainer.addConstraint(NSLayoutConstraint(item: titleView, attribute: .CenterX, relatedBy: .Equal, toItem: titleContainer, attribute: .CenterX, multiplier: 1.0, constant: 0.0))
return titleContainer;
}
}
A UIView subclass that implements the protocol:
class MyContentView:UIView, MyProtocol, UITextFieldDelegate{
weak var myActiveView:UIView?
init(){
super.init(frame: CGRectZero)
self.backgroundColor = UIColor.clearColor()
self.opaque = false
self.translatesAutoresizingMaskIntoConstraints = false
let cells = Array(1...12).map{_ in cellView() }
var cellsDictionary: Dictionary<String, UIView> = [:], cellsVerticalFormat = "V:|-"
for (idx, cell) in cells.enumerate(){
self.addSubview(cell)
self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-[cell]-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["cell": cell]))
let cellKey = "cell\(idx)"
cellsDictionary[cellKey] = cell
cellsVerticalFormat = cellsVerticalFormat + "[\(cellKey)]-"
}
cellsVerticalFormat = cellsVerticalFormat + "|"
self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat(cellsVerticalFormat, options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: cellsDictionary))
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
func cellView() -> UIView{
let result = UIView()
result.backgroundColor = UIColor.magentaColor()
result.translatesAutoresizingMaskIntoConstraints = false
let text = UITextField()
text.translatesAutoresizingMaskIntoConstraints = false
result.addSubview(text)
text.delegate = self
result.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-[text]-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["text": text]))
result.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[text]-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["text": text]))
return result
}
func widgets() {
print("\(MyContentView.self) widgets")
}
func activeView() -> UIView? {
return myActiveView
}
func textFieldShouldBeginEditing(textField: UITextField) -> Bool{
myActiveView = textField.superview!
return true
}
func textFieldDidEndEditing(textField: UITextField) {
if myActiveView === textField.superview! {
myActiveView = nil
}
}
func textFieldShouldEndEditing(textField: UITextField) -> Bool {
return true
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return false
}
}
A KeyboardAwareViewController subclass:
class MyKeyboardAwareScrollViewController : KeyboardAwareScrollViewController<MyContentView>{
let myContentView: MyContentView = MyContentView()
let myTitleView: UILabel = {
let result = UILabel()
result.translatesAutoresizingMaskIntoConstraints = false
result.text = "Pretend This Says\nCohn-Reznick"
result.numberOfLines = 0
result.textAlignment = .Center
return result
}()
required init?(coder aDecoder: NSCoder) {
super.init(titleView: myTitleView, contentView:myContentView)
}
}

Answer 1

Answer is here: Xcode 7 Swift 2 impossible to instantiate UIViewController subclass of generic UITableViewController
TLDR; Objective-c and InterfaceBuilder can't "see" generic swift classes.