ios - 添加项目时使 uitextfield 滚动到底部

Question

我有一个 collectionViewController 和一个 inputContainerAccessoryView，里面有一个 uitextfield。每次我在键盘上按回车，一个项目(一行)被添加到collectionview，我想让collectionview自动滚动到它的底部；我还希望当键盘出现时，它也会滚动到 Collection View 的底部。我试过一个代码，但没有按我想要的方式滚动:

viewDidLoad

collectionView?.keyboardDismissMode = .interactive
    
    NotificationCenter.default.addObserver(
        self,
        selector: #selector(HomeViewController.keyboardWillShow(event:)),
        name: NSNotification.Name.UIKeyboardWillShow,
        object: nil
    )

文本字段应该返回

handleKeyboardDidShow()

方法

func keyboardWillShow(event: Notification) {
    //let keyboardqlq = inputTextField.frame.height
    guard let keyboardFrame = (event.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else { return }
    guard let colelctionview = self.collectionView else { return }
    
    colelctionview.contentInset.bottom = keyboardFrame.height - 200
    colelctionview.scrollIndicatorInsets.bottom = keyboardFrame.height - 200
    
    // do NOT scroll messages if the keyboard is the `accessoryView`
    if keyboardFrame.height != inputContainerView.frame.height {
        handleKeyboardDidShow()
    }
}


func handleKeyboardDidShow() {
    
    if messages.count > 0 {
        let indexPath = IndexPath(item: messages.count - 1, section: 0)
        collectionView?.scrollToItem(at: indexPath, at: .bottom, animated: true)
    }
}

Answer 1

也许它效率不高，但它解决了问题。确保文本字段委托(delegate)是自己的。

 var needToScroll :Bool = true

func textFieldDidBeginEditing(_ textField: UITextField) {
        needToScroll = true
    }
func handleKeyboardWillHide(notification:Notification) {
    let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
    
    UIView.animate(withDuration: keyboardDuration!) {
        self.view.layoutIfNeeded()
             self.chatLogCollectionView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 30, right: 0)
     
        self.needToScroll = false
    }
    
}
func handleKeyboardWillShow(notification:Notification) {
  
    let keyboardFrame = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect
     let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
    
    UIView.animate(withDuration: keyboardDuration!) {
        self.view.layoutIfNeeded()
        self.chatLogCollectionView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: (keyboardFrame?.height)!, right: 0)
        
        
        if self.needToScroll {
            if self.chatLogCollectionView.messages.count > 0 {
                
                self.chatLogCollectionView.scrollToItem(at: NSIndexPath(item: self.chatLogCollectionView.messages.count - 1, section: 0) as IndexPath, at: .bottom, animated: false)
            }
        }
        
    }
   
    }