使用iOS SDK：
我有一个带UITextFields的UIView，可以启动键盘。我需要它能够：
启动键盘后，允许滚动UIScrollView的内容以查看其他文本字段自动“跳转”（通过向上滚动）或缩短
我知道我需要一个UIScrollView。我已经尝试将UIView的类更改为UIScrollView，但仍然无法上下滚动文本框。
我需要UIView和UIScrollView吗？一个在另一个里面吗？
要自动滚动到活动文本字段，需要执行哪些操作？
理想情况下，尽可能多的组件设置将在Interface Builder中完成。我只想编写需要的代码。
注意：我使用的UIView（或UIScrollView）是由一个选项卡（UITabBar）启动的，它需要正常工作。
我正在添加滚动条，只为键盘出现时使用。尽管不需要它，但我觉得它提供了一个更好的界面，例如，用户可以滚动和更改文本框。
当键盘上下移动时，我可以改变UIScrollView的框架大小。我只是在使用：
-(void)textFieldDidBeginEditing:(UITextField *)textField {
//Keyboard becomes visible
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height - 215 + 50); // Resize
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
// Keyboard will hide
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height + 215 - 50); // Resize
}
然而，这不会自动“向上移动”或将可见区域中的下部文本字段居中，这是我真正想要的。
Swift 3.0版本的苹果键盘管理代码如下：以下代码中使用的FloatingTF是iOS中基于材质设计的文本字段。
import UIKit
class SignupViewController: UIViewController, UITextFieldDelegate {
//MARK: - IBOutlet:
@IBOutlet weak var emailTF: FloatingTF!
@IBOutlet weak var passwordTF: FloatingTF!
@IBOutlet weak var dobTF: FloatingTF!
@IBOutlet weak var scrollView: UIScrollView!
//MARK: - Variable:
var activeTextField: UITextField!
//MARK: - ViewController Lifecycle:
override func viewDidLoad() {
super.viewDidLoad()
emailTF.delegate = self
passwordTF.delegate = self
dobTF.delegate = self
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
registerKeyboardNotifications()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
deRegisterKeyboardNotifications()
}
//MARK: - Keyboard notification observer Methods
fileprivate func registerKeyboardNotifications() {
NotificationCenter.default.addObserver(self, selector: #selector(SignupViewController.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(SignupViewController.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
fileprivate func deRegisterKeyboardNotifications() {
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: self.view.window)
NotificationCenter.default.removeObserver(self, name: .UIKeyboardDidHide, object: self.view.window)
}
func keyboardWillShow(notification: NSNotification) {
let info: NSDictionary = notification.userInfo! as NSDictionary
let value: NSValue = info.value(forKey: UIKeyboardFrameBeginUserInfoKey) as! NSValue
let keyboardSize: CGSize = value.cgRectValue.size
let contentInsets: UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height, 0.0)
scrollView.contentInset = contentInsets
scrollView.scrollIndicatorInsets = contentInsets
// If active text field is hidden by keyboard, scroll it so it's visible
// Your app might not need or want this behavior.
var aRect: CGRect = self.view.frame
aRect.size.height -= keyboardSize.height
let activeTextFieldRect: CGRect? = activeTextField?.frame
let activeTextFieldOrigin: CGPoint? = activeTextFieldRect?.origin
if (!aRect.contains(activeTextFieldOrigin!)) {
scrollView.scrollRectToVisible(activeTextFieldRect!, animated:true)
} }
func keyboardWillHide(notification: NSNotification) {
let contentInsets: UIEdgeInsets = .zero
scrollView.contentInset = contentInsets
scrollView.scrollIndicatorInsets = contentInsets
}
//MARK: - UITextField Delegate Methods
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
if textField == emailTF {
passwordTF.becomeFirstResponder()
}
else if textField == passwordTF {
dobTF.becomeFirstResponder()
}
else {
self.view.endEditing(true)
}
return true
}
func textFieldDidBeginEditing(_ textField: UITextField) {
activeTextField = textField
scrollView.isScrollEnabled = true
}
func textFieldDidEndEditing(_ textField: UITextField) {
activeTextField = nil
scrollView.isScrollEnabled = false
}
}
我使用Swift和自动布局（但不能评论之前的Swift答案）；以下是我在没有滚动视图的情况下的操作方法：
我在IB中使用字段之间的垂直约束来布局表单，以分隔它们。我在容器视图的最顶部字段中添加了一个垂直约束，并为此创建了一个出口（下面代码中的topSpaceForFormConstraint）。所有需要的就是更新这个约束，这是我在动画块中为一个漂亮的软运动所做的。当然，高度检查是可选的，在这种情况下，我只需要对最小的屏幕尺寸进行检查。
这可以使用任何常用的textFieldDidBegginEditing或keyboardWillShow方法调用。
func setFormHeight(top: CGFloat)
{
let height = UIScreen.mainScreen().bounds.size.height
// restore text input fields for iPhone 4/4s
if (height < 568) {
UIView.animateWithDuration(0.2, delay: 0.0, options: nil, animations: {
self.topSpaceForFormConstraint.constant = top
self.view.layoutIfNeeded()
}, completion: nil)
}
}
