滚动视图内的文本字段仅在键盘出现后向上移动 IOS

Question

我有以下问题：我有一个

scrollView

，里面有一个

textField

。我需要当我点击

textField

时，键盘会显示出来，并且

textField

（在滚动条内）立即向上移动（同时）键盘显示。现在

textField

出现，但有延迟，就像键盘显示后几毫秒，如下所示：

更新：

我已经重写了键盘处理方法，如下所示：

override func keyboardWillShow(_ notification: Notification!) {
    guard let userInfo = notification.userInfo, let frame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
        return
    }

    // this constraint -> viewContainerButtonBottomConstraint 
    //refers to the button that must have above the keyboard 
    //when keyboard shows up.   
    self.viewContainerButtonBottomConstraint.constant = frame.height
    UIView.animate(withDuration: 0.3, animations: {
        self.view.layoutIfNeeded()
    }, completion: nil)

    let contentInset = UIEdgeInsets(top: 0, left: 0, bottom: frame.height, right: 0)
    scrollView.contentInset = contentInset
    
    if #available(iOS 11.0, *) {
        self.viewContainerButtonBottomConstraint.constant -= self.view.safeAreaInsets.bottom
    }
}

override func keyboardWillHide(_ notification: Notification!) {
    scrollView.contentInset = UIEdgeInsets.zero
    
    self.viewContainerButtonBottomConstraint.constant = 0
    
    UIView.animate(withDuration: 1, animations: {
        self.view.layoutIfNeeded()
    }, completion: nil)
} 

观察者的注册是在父类中进行的：

- (void)addNotificationKeyboard {
    if (kKeyboardNotificationsShowAvailable) {
     [[NSNotificationCenter defaultCenter] addObserver:self
                                           
     selector:@selector(keyboardWillShowNotification:)
                                                 
     name:UIKeyboardWillShowNotification
                                               object:nil];
   }
   if (kKeyboardNotificationsHideAvailable) {
     [[NSNotificationCenter defaultCenter] addObserver:self
                                             
     selector:@selector(keyboardWillHideNotification:)
                                                 
     name:UIKeyboardWillHideNotification
                                               object:nil];
}

}

方法keyboardWillShowNotification和keyboardWillHideNotification也在父类中，它们被重写，就像我上面展示的那样：

- (void)keyboardWillShowNotification:(NSNotification*)notification
{
   NSDictionary* keyboardInfo = [notification userInfo];
   NSValue* keyboardFrameBegin = [keyboardInfo 
   valueForKey:UIKeyboardFrameEndUserInfoKey];
   self.keyboardHeight = [keyboardFrameBegin CGRectValue].size.height;
}

- (void)keyboardWillHideNotification:(NSNotification*)notification
{
    if (self.view.frame.origin.y != 0) {
    if (self.tabBarController) {
        if (!(self.view.frame.origin.y == 64))
            [UIUtilities moveView:self.view newYposition:-64];
    }
    else
        [UIUtilities moveView:self.view newYposition:0];
    }
    [self.view endEditing:YES];
}

提前感谢您的回答！

Answer 1

你想要的并不难做到。在显示键盘之前会发送一个名为

UIKeyboardWillShow

的系统通知。注意这一点。它的用户信息包含有关键盘在屏幕上时的大小和位置的所有信息，以及用于将键盘移至屏幕上的动画。然后您所要做的就是立即启动匹配的动画来移动或调整您的显示。两个动画将同时运行。

Answer 2

这就是我所拥有的：

@objc func adjustForKeyboard(notification: Notification)
{
    let userInfo = notification.userInfo!
    let keyboardScreenEndFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
    let keyboardViewEndFrame = view.convert(keyboardScreenEndFrame, from: view.window)

    if notification.name == Notification.Name.UIKeyboardWillHide
    {
        self.scrollForm.contentInset = UIEdgeInsets.zero
    }
    else
    {
        self.scrollForm.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardViewEndFrame.height, right: 0)
    }
    self.scrollForm.scrollIndicatorInsets = self.scrollForm.contentInset
    //let selectedRange = self.scrollForm.selectedRange
    //self.scrollForm.scrollRangeToVisible(selectedRange)
}

并且在

viewDidLoad()

内：

    let notificationCenter = NotificationCenter.default
    notificationCenter.addObserver(self, selector: #selector(adjustForKeyboard), name: Notification.Name.UIKeyboardWillHide, object: nil)
    notificationCenter.addObserver(self, selector: #selector(adjustForKeyboard), name: Notification.Name.UIKeyboardWillChangeFrame, object: nil)

这可能与您所拥有的类似，请尝试用上面的内容替换您的覆盖。