swift animation not work in UIKeyboardWillShowNotification event - swift

Question

I don't know why animation work fine in UIKeyboardDidShowNotification event but not work in UIKeyboardWillShowNotification event.
Code looks like this:
anim in the comment code not work good, color will change but duration = 4 is not right
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardDidShow:"), name:UIKeyboardDidShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardDidHide:"), name:UIKeyboardDidHideNotification, object: nil)
}
deinit {NSNotificationCenter.defaultCenter().removeObserver(self)}
func keyboardDidShow(notification: NSNotification) {
showAnima1()
}
func keyboardDidHide(notification: NSNotification) {
showAnima2()
}
func keyboardWillShow(notification: NSNotification) {
// showAnima1() // animate not work here
}
func keyboardWillHide(notification: NSNotification) {
// showAnima2() // animate not work here
}
func showAnima1() {
UIView.animateWithDuration(4, delay: 0, options: UIViewAnimationOptions(rawValue: 7), animations: { () -> Void in
self.view.backgroundColor = UIColor.greenColor()
}) { (finish) -> Void in
print("animate state = \(finish)")
}
}
func showAnima2() {
UIView.animateWithDuration(4, delay: 0, options: UIViewAnimationOptions(rawValue: 7), animations: { () -> Void in
self.view.backgroundColor = UIColor.whiteColor()
}) { (finish) -> Void in
print("animate state = \(finish)")
}
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {self.view.endEditing(false)}
}
Sorry, i see comment in source code says:
// Each notification includes a nil object and a userInfo dictionary containing the
// begining and ending keyboard frame in screen coordinates. Use the various UIView and
// UIWindow convertRect facilities to get the frame in the desired coordinate system.
// Animation key/value pairs are only available for the "will" family of notification.
The last comment maybe it means "did" family of notification???

Answer 1

I had the same problem.
It looks like the animate function has to be called from the main thread. Wrapping the animation in DispatchQueue.main.async worked for me:
#objc func keyboardWillHide(notification: NSNotification) {
DispatchQueue.main.async {
UIView.animate(withDuration: 2.0) {
self.view.frame.origin.y = 0
}
}
}