[英]Back animation of UIButton doesn't work
我有一個文本視圖(textView)和一個按鈕(sendButton)。 按鈕的底部約束是對視圖底部的約束。 textView成為viewDidAppear中的第一個響應者。 因此,當我提出控制器時,鍵盤會上升,並且按鈕也會隨之動畫。
這是代碼:
override func viewDidLoad() {
super.viewDidLoad()
setupSendButton()
dismissKeyboard()
}
override func viewDidAppear(_ animated: Bool) {
textView.becomeFirstResponder()
}
func setupSendButton() {
self.view.addSubview(sendButton)
sendButton.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
sendButton.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
sendButton.heightAnchor.constraint(equalToConstant: 60).isActive = true
sendButton.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
sendButton.translatesAutoresizingMaskIntoConstraints = false
}
// TextView Delegate Method
func textViewDidBeginEditing(_ textView: UITextView) {
// Animation begins after textView did begin editing
animateSendButton(bottomConstraint: -216)
}
至此,一切正常。
我的問題是,當我關閉鍵盤並結束編輯時,我想重新設置動畫,以便按鈕的底部約束再次成為視圖的底部約束。
但這是行不通的。
// TextView Delegate Method
func textViewDidEndEditing(_ textView: UITextView) {
// Animation begins after textView did end editing (it doesn't)
animateSendButton(bottomConstraint: 0)
}
// function to dismiss keyboard and end editing
func dismissKeyboard() {
let touch = UITapGestureRecognizer(target: self, action: #selector(tapGesture))
self.view.addGestureRecognizer(touch)
}
@objc func tapGesture(gesture: UITapGestureRecognizer){
// Ends editing and dismisses keyboard
self.view.endEditing(true)
}
動畫按鈕功能:animateSendButton(底部約束:CGFloat)
func animateSendButton(bottomConstraint: CGFloat) {
sendButton.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: bottomConstraint).isActive = true
UIView.animate(withDuration: 0.55, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseIn, animations: {
self.view.layoutIfNeeded()
}, completion: nil)
}
您必須先刪除之前的底部約束,然后再添加其他約束
或改變
var bottomCon:NSLayoutConstraint!
//////
func setupSendButton() {
self.view.addSubview(sendButton)
sendButton.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
sendButton.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
sendButton.heightAnchor.constraint(equalToConstant: 60).isActive = true
self.bottomCon = sendButton.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
self.bottomCon.active= true
sendButton.translatesAutoresizingMaskIntoConstraints = false
}
func animateSendButton(bottomConstraint: CGFloat) {
self.bottomCon.constant = bottomConstraint
UIView.animate(withDuration: 0.55, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseIn, animations: {
self.view.layoutIfNeeded()
}, completion: nil)
}
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