Question

我有UIScrollView，其中有一个UIView（基本上是一个内容视图）。在contentView中，我有UITextFields和一个UIButton。首先，元素直接位于UIScrollView内部。键盘打开时，如果UITextField在键盘下方，则滚动视图滚动以显示内容。之后，我将它们放入ContentView中，它开始没有任何作用。我究竟做错了什么？

我搜索了以下帖子，但不确定为什么我的代码不起作用。

How do I scroll the UIScrollView when the keyboard appears?

P.S：我知道社区中有很多例子，但是我不确定哪种方法最好。当这个程序工作时，这是一个简单而轻松的答案，但是不确定为什么不工作。

@objc override func keyboardWillShow(notification: NSNotification){
//Need to calculate keyboard exact size due to Apple suggestions
if let frameValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
    keyboardHeight = frameValue.cgRectValue.size.height

        let contentInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardHeight, right: 0.0)
        self.scrollView.contentInset = contentInsets
        self.scrollView.scrollIndicatorInsets = contentInsets
}
}

我如何施加约束：

contentView.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(contentView)
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
scrollView.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(scrollView)

contentView.addSubview(TextField1)
contentView.addSubview(TextField2)
contentView.addSubview(button)
scrollView.anchor(header.bottomAnchor, left: self.view.leftAnchor, bottom: self.view.bottomAnchor, right: self.view.rightAnchor, topConstant: 20, leftConstant: 0, bottomConstant: 0, rightConstant: 0, widthConstant: 0, heightConstant: 0)
TextField1.anchor(contentView.topAnchor, left: self.contentView.leftAnchor, bottom: nil, right: self.contentView.rightAnchor, topConstant: 5, leftConstant: 25, bottomConstant: 0, rightConstant: 25, widthConstant: 0, heightConstant: 70)
TextField1.widthAnchor.constraint(equalTo: self.view.widthAnchor, constant: -50).isActive = true

TextField2.anchor(TextField1.bottomAnchor, left: self.contentView.leftAnchor, bottom: nil, right: self.contentView.rightAnchor, topConstant: 5, leftConstant: 25, bottomConstant: 0, rightConstant: 25, widthConstant: 0, heightConstant: 70)
Button.anchor(TextField2.bottomAnchor, left: self.contentView.leftAnchor, bottom: self.contentView.bottomAnchor, right: self.contentView.rightAnchor, topConstant: 30, leftConstant: 25, bottomConstant: 20, rightConstant: 25, widthConstant: 0, heightConstant: 40)

编辑：我尝试了另一种方法（Apple建议）。 aRect.Contains始终返回true。

    if let frameValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
    keyboardHeight = frameValue.cgRectValue.size.height

    var contentInsets: UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardHeight, right: 0.0)
    scrollView.contentInset = contentInsets
    scrollView.scrollIndicatorInsets = contentInsets

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    //CGRect(x: 0, y: self.header.frame.maxY, width: self.view.frame.width, height: self.view.frame.height - self.header.frame.maxY)
    var aRect: CGRect = self.view.frame
    aRect.size.height -= keyboardHeight
    aRect.size.height -= header.frame.maxY
    if !aRect.contains(activeTextField.frame.origin) {
        var scrollPoint = CGPoint(x: 0.0, y: activeTextField.frame.origin.y - (keyboardHeight))
        scrollView.setContentOffset(scrollPoint, animated: true)
    }
    }

Answer 1

一个小时的工作后，我找到了解决方案。我共享答案而不是删除帖子，我的问题是因为UIScrollView不能满足整个屏幕的需求。 UIScrollView上方有一个标题和一个标签。社区中的所有答案均以UIScroll内容是否全屏为目标。

       @objc override func keyboardWillShow(notification: NSNotification){
    //Need to calculate keyboard exact size due to Apple suggestions
    if let frameValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        keyboardHeight = frameValue.cgRectValue.size.height
        let scrollViewRect: CGRect = view.convert(scrollView.frame, from: scrollView.superview)
        let hiddenScrollViewRect: CGRect = scrollViewRect.intersection(frameValue.cgRectValue)

        // Figure out where the two frames overlap, and set the content offset of the scrollview appropriately
        let contentInsets: UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: hiddenScrollViewRect.size.height, right: 0.0)
        scrollView.contentInset = contentInsets
        scrollView.scrollIndicatorInsets = contentInsets

        var visibleRect: CGRect = activeTextField.frame
        visibleRect = scrollView.convert(visibleRect, from: activeTextField.superview)
        visibleRect = visibleRect.insetBy(dx: 0.0, dy: -5.0)
        scrollView.scrollRectToVisible(visibleRect, animated: true)
    }

Answer 2

实现此目标的简单方法是使用IQKeyboardManager库。

签出链接：https://github.com/hackiftekhar/IQKeyboardManager

如果出现ContentView中的元素，则在出现键盘时ScrollView不滚动

2 个答案: