ios - swift 为 collectionView 正确关闭键盘

Question

我正在创建一个简单的 Messenger 聊天窗口，我正在使用 UICollectionView 作为我的气泡消息。现在我想设置键盘以正确显示和隐藏。我使用了 NSNotifications 并为 keyboardWillShow: 和 keyboardWillHide: 事件创建了函数。我还为我的 CollectionView 将 keyboardDismissMode 设置为 Interactive。所以现在，当我向上滚动时，我的键盘隐藏了(由交互式关闭模式引起)，我还收到了 keyboardWillHide 事件，它重置了我的 UIEdgeInsets。所以基本上在我向上滚动并且我的键盘被隐藏后，我的 scrollView 立即进入底部。我的目标是让它像在 iMessage.app、WhatsApp 等中一样工作。我将不胜感激任何帮助或建议!

这是我的代码:

class ViewController: UIViewController {

   @IBOutlet weak var collectionView: UICollectionView!
   var customView: CustomView!

    override func viewDidLoad() {
       super.viewDidLoad()
       customView = CustomView(frame: CGRectMake(0, 0, UIScreen.mainScreen().bounds.width, 40.0))
       customView.textView!.delegate = self
       collectionView.scrollToBottom(true)
       collectionView.keyboardDismissMode = UIScrollViewKeyboardDismissMode.Interactive

       NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
       NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)

    }

   override var inputAccessoryView: UIView! {
       get {
           if customView == nil {
               customView = CustomView()
           }
           return customView
          }
       }

   override func canBecomeFirstResponder() -> Bool {
      return true
   }

   func keyboardWillShow(notification: NSNotification) {
        let userInfo = notification.userInfo ?? [:]
        let keyboardFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()
        let adjustmentHeight = (CGRectGetHeight(keyboardFrame) + CGRectGetHeight(customView.frame) )
        let contentInset:UIEdgeInsets
        if UIInterfaceOrientationIsPortrait(UIApplication.sharedApplication().statusBarOrientation) {
            contentInset = UIEdgeInsetsMake(0, 0, adjustmentHeight, 0)
        } else {
            contentInset = UIEdgeInsetsMake(0, 0, keyboardFrame.width, 0)
        }
        collectionView.contentInset = contentInset
        collectionView.scrollIndicatorInsets = contentInset
        collectionView.scrollToBottom(true)
  }

   func keyboardWillHide(notification: NSNotification) {
       collectionView.contentInset = UIEdgeInsetsZero
       collectionView.scrollIndicatorInsets = UIEdgeInsetsZero
   }



}

Answer 1

当您以交互方式关闭键盘时，您的 collectionView 滚动到底部不是因为 UIEdgeInsets 被重置为零，而是因为在此配置中，当您以交互方式关闭键盘时，将再次调用 keyboardWillShow 方法。大概是因为inputAccessoryView。要验证这一点，请将 println 放入您的 keyboardWillShow 方法中，然后再试一次。我想说这是评论而不是答案，但我只有 47 个代表，需要 50 个才能发表评论。但我认为这些信息可能对您有用。