Strange delay displaying text in input accessory view during push animation. - ios

Question

I'm facing problem when string in UILabel is displayed with delay in inputAccessoryView on UIViewController. I have attached gif demonstrating this problem. After pushing SecondViewController to navigation stack inputAccessoryView is missing text for short time. But I want text to be shown right away after opening screen.
Implementation demonstrating this problem is extremely simple.
class SecondViewController: UIViewController {
#IBOutlet var accessoryView: UIView!
override var inputAccessoryView: UIView {
return accessoryView
}
override func canBecomeFirstResponder() -> Bool {
return true
}
}
Does any one have solution for this problem?

Answer 1

I have come up with the solution which works on both iOS 8 and 9. Also it address retain cycle issue presented in iOS 9 which prevent view controller from being deallocated when use inputaccessoryview. Check github project for more details.
With lots of experimentation I have found quite hacky solution but works like a charm. Just subclass your implemantation accessory view from AccessoryView listed below.
class AccessoryView: UITextField {
override var canBecomeFirstResponder: Bool {
return true
}
override func awakeFromNib() {
super.awakeFromNib()
disableShowingKeyboard()
hideCursor()
}
}
extension AccessoryView {
private func disableShowingKeyboard() {
inputView = UIView()
}
private func hideCursor() {
tintColor = UIColor.clear
}
override func accessibilityActivate() -> Bool {
return false
}
override var isEditing: Bool {
return false
}
override func caretRect(for position: UITextPosition) -> CGRect {
return .zero
}
override func selectionRects(for range: UITextRange) -> [UITextSelectionRect] {
return []
}
override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
if action == #selector(UIResponder.copy(_:)) || action == #selector(UIResponder.selectAll(_:)) || action == #selector(UIResponder.paste(_:)){
return false
}
return super.canPerformAction(action, withSender: sender)
}
override func addGestureRecognizer(_ gestureRecognizer: UIGestureRecognizer) {
if gestureRecognizer is UILongPressGestureRecognizer {
gestureRecognizer.isEnabled = false
}
super.addGestureRecognizer(gestureRecognizer)
}
}
extension AccessoryView {
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
for view in subviews {
let _point = self.convert(point, to: view)
if !view.isHidden && view.isUserInteractionEnabled && view.alpha > 0.01 && view.point(inside: _point, with: event) {
if let _view = view.hitTest(_point, with: event){
return _view
}
}
}
return super.hitTest(point, with: event)
}
}