我目前正在开发使用 Swift 3 的 iPhone 应用程序,但是我在滚动视图时遇到了问题。在选择文本字段并显示键盘之前,滚动视图正常工作(即:我可以上下滚动),但是关闭键盘后,滚动视图不允许我再滚动,这是我的问题。注意:如果我再次选择一个文本字段并使键盘出现,它工作正常,一旦再次关闭它就会停止工作。
我已经检查了滚动视图的 isScrollEnabled 属性,它似乎已启用。不幸的是,我仍然不太熟悉滚动视图的所有细节,似乎无法弄清楚它停止工作的原因。
任何关于我可以看哪里的帮助或指示将不胜感激。
编辑:有相当多的代码,但这是与滚动视图和键盘相关的缩小部分:
class ScrollViewController: UIViewController, UITextViewDelegate, UITextFieldDelegate {
//Scroll view
@IBOutlet weak var scrollView: UIScrollView!
//UIView inside the scroll view
@IBOutlet weak var contentView: UIView!
//Save button on the top right corner
@IBOutlet weak var saveButton: UIBarButtonItem!
//Text field being editted
var activeTextField:UITextField?
fileprivate var contentInset:CGFloat?
fileprivate var indicatorInset:CGFloat?
override func viewDidLoad() {
contentInset = scrollView.contentInset.bottom
indicatorInset = scrollView.scrollIndicatorInsets.bottom
NotificationCenter.default.addObserver(self,
selector: #selector(ScrollViewController.keyboardWillShow(_:)),
name: NSNotification.Name.UIKeyboardWillShow,
object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(ScrollViewController(_:)),
name: NSNotification.Name.UIKeyboardWillHide,
object: nil)
}
func adjustInsetForKeyboardShow(_ show: Bool, notification: Notification) {
let userInfo = notification.userInfo ?? [:]
let keyboardFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let adjustmentHeight = (keyboardFrame.height + 20) * (show ? 1 : -1)
scrollView.contentInset.bottom = (contentInset! + adjustmentHeight)
scrollView.scrollIndicatorInsets.bottom = (indicatorInset! + adjustmentHeight)
}
func keyboardWillShow(_ notification: Notification) {
adjustInsetForKeyboardShow(true, notification: notification)
}
func keyboardWillHide(_ notification: Notification) {
adjustInsetForKeyboardShow(false, notification: notification)
}
//Tap gesture to dismiss the keyboard
@IBAction func hideKeyboard(_ sender: AnyObject) {
self.view.endEditing(false)
}
deinit {
NotificationCenter.default.removeObserver(self);
}
}
我已经创建了UIViewController的扩展并为scrollView创建了方法。只需要从 viewWillAppear() 和 viewDidDisappear() 调用
extension UIViewController {
func registerForKeyboradDidShowWithBlock (scrollview:UIScrollView ,block: ((CGSize?) -> Void)? = nil ){
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIKeyboardDidShow, object: nil, queue: nil) { (notification) in
if let userInfo = (notification as NSNotification).userInfo {
if let keyboarRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.findFirstResponder() != nil {
let keyboarRectNew = self.view .convert(keyboarRect, to: self.view)
let scrollViewSpace = scrollview.frame.origin.y + scrollview.contentOffset.y
let textFieldRect:CGRect = self.view.findFirstResponder()!.convert(self.view.findFirstResponder()!.bounds, to: self.view)
let textFieldSpace = textFieldRect.origin.y + textFieldRect.size.height
let remainingSpace = self.view.frame.size.height - keyboarRectNew.size.height
if scrollViewSpace + textFieldSpace > remainingSpace {
let gap = scrollViewSpace + textFieldSpace - remainingSpace
scrollview .setContentOffset(CGPoint(x: scrollview.contentOffset.x, y: gap), animated: true)
}
}
}
}
block?(CGSize.zero)
}
}
func registerForKeyboardWillHideNotificationWithBlock ( scrollview:UIScrollView ,block: ((Void) -> Void)? = nil) {
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIKeyboardWillHide, object: nil, queue: nil, using: { (notification) -> Void in
scrollview.scrollRectToVisible(CGRect(x: 0, y: 0, width: 0, height: 0), animated: true)
scrollview.contentOffset = CGPoint(x: 0, y: 0)
scrollview.contentInset = UIEdgeInsetsMake(0.0, 0.0, 0.0, 0.0)
scrollview.scrollIndicatorInsets = UIEdgeInsetsMake(0.0, 0.0, 0.0, 0.0);
block?()
})
}
func deregisterKeyboardShowAndHideNotification (){
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
self.view.findFirstResponder()?.resignFirstResponder()
}
}
我已经创建了UIView
的扩展,以在其中创建查找第一响应者方法。
extension UIView {
func findFirstResponder() -> UIView? {
if self.isFirstResponder {
return self
}
for subview: UIView in self.subviews {
let firstResponder = subview.findFirstResponder()
if nil != firstResponder {
return firstResponder
}
}
return nil
}
}
<</div>
div class="one_answers"> 创建 UIView 的扩展并记下此方法。
extension UIView {
func findFirstResponder() -> UIView? {
if self.isFirstResponder {
return self
}
for subview: UIView in self.subviews {
let firstResponder = subview.findFirstResponder()
if nil != firstResponder {
return firstResponder
}
}
return nil
}
}
他们是 Objective C 中的第三方库,用于处理具有滚动视图、集合视图和表格视图的键盘。库的名称是 tpkeyboardavoidingscrollview。如果可能,请尝试嵌入此内容。