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。


当前回答

我们可以为Swift 4.1提供用户给定的代码

    let keyBoardSize = 80.0

    func keyboardWillShow() {

    if view.frame.origin.y >= 0 {
    viewMovedUp = true
     }
     else if view.frame.origin.y < 0 {
    viewMovedUp = false
   }
  }

func keyboardWillHide() {
 if view.frame.origin.y >= 0 {
    viewMovedUp = true
 }
 else if view.frame.origin.y < 0 {
    viewMovedUp = false
 }

}

func textFieldDidBeginEditing(_ textField: UITextField) {
   if sender.isEqual(mailTf) {
    //move the main view, so that the keyboard does not hide it.
    if view.frame.origin.y >= 0 {
        viewMovedUp = true
    }
  }
}

func setViewMovedUp(_ movedUp: Bool) {
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationDuration(0.3)
    // if you want to slide up the view
let rect: CGRect = view.frame
if movedUp {

    rect.origin.y -= keyBoardSize
    rect.size.height += keyBoardSize
}
else {
    // revert back to the normal state.
    rect.origin.y += keyBoardSize
    rect.size.height -= keyBoardSize
 }
 view.frame = rect
 UIView.commitAnimations()
}

func viewWillAppear(_ animated: Bool)  {
super.viewWillAppear(animated)

NotificationCenter.default.addObserver(self, selector:#selector(self.keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector:#selector(self.keyboardWillHide), name: .UIKeyboardWillHide, object: nil)
}

func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)

NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
}

其他回答

它很简单:-

在TextFieldDidBegginEditing中:-

self.view.frame=CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y-150, self.view.frame.size.width, self.view.frame.size.height);

在TextFieldShouldEndEditing中:-

self.view.frame=CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y+150, self.view.frame.size.width, self.view.frame.size.height);

对于Swift程序员:

这将为您完成所有工作,只需将这些放在视图控制器类中,并将UITextFieldDelegate实现到视图控制器,并将textField的委托设置为self

textField.delegate = self // Setting delegate of your UITextField to self

实现委托回调方法:

func textFieldDidBeginEditing(textField: UITextField) {
    animateViewMoving(true, moveValue: 100)
}

func textFieldDidEndEditing(textField: UITextField) {
    animateViewMoving(false, moveValue: 100)
}

// Lifting the view up
func animateViewMoving (up:Bool, moveValue :CGFloat){
    let movementDuration:NSTimeInterval = 0.3
    let movement:CGFloat = ( up ? -moveValue : moveValue)
    UIView.beginAnimations( "animateView", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(movementDuration )
    self.view.frame = CGRectOffset(self.view.frame, 0,  movement)
    UIView.commitAnimations()
}

对于Swift 4、4.2、5:改变

self.view.frame = CGRectOffset(self.view.frame, 0,  movement)

to

self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)

关于此实现的最后一点注意事项:如果在显示键盘时将另一个视图控制器推到堆栈上,这将产生一个错误,其中视图返回到其中心框架,但键盘偏移未重置。例如,您的键盘是nameField的第一个响应者,但随后您按下一个按钮,将帮助视图控制器推到堆栈上。若要修复偏移错误,请确保在离开视图控制器之前调用nameField.issentFirstResponder(),确保同时调用textFieldDidEndEditing委托方法。我在viewWillDisappear方法中这样做。

试试这个小把戏。

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    [self animateTextField: textField up: YES];
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    [self animateTextField: textField up: NO];
}

- (void) animateTextField: (UITextField*) textField up: (BOOL) up
{
    const int movementDistance = textField.frame.origin.y / 2; // tweak as needed
    const float movementDuration = 0.3f; // tweak as needed

    int movement = (up ? -movementDistance : movementDistance);

    [UIView beginAnimations: @"anim" context: nil];
    [UIView setAnimationBeginsFromCurrentState: YES];
    [UIView setAnimationDuration: movementDuration];
    self.view.frame = CGRectOffset(self.view.frame, 0, movement);
    [UIView commitAnimations];
}

虽然这条线索已经得到了足够的答案,但我想建议一种更简单但更通用的方法,就像苹果一样,将键盘的高度考虑在内,这在我们使用键盘顶部的自定义工具栏时非常有用。尽管苹果在这方面的做法没有什么问题。

这是我的方法(略微修改了苹果的方法)-

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;
}

对于Swift Developer,使用Swift 3,这里是回购https://github.com/jamesrochabrun/KeyboardWillShow

import UIKit

class ViewController: UIViewController {

    //1 Create a view that will hold your TEXTFIELD
    let textField: UITextField = {
        let tf = UITextField()
        tf.translatesAutoresizingMaskIntoConstraints = false
        tf.layer.borderColor = UIColor.darkGray.cgColor
        tf.layer.borderWidth = 3.0
        return tf
    }()
    //2 global variable that will hold the bottom constraint on changes
    var textfieldBottomAnchor: NSLayoutConstraint?

    override func viewDidLoad() {
        super.viewDidLoad()
        //3 add the view to your controller
        view.addSubview(textField)
        textField.heightAnchor.constraint(equalToConstant: 80).isActive = true
        textField.widthAnchor.constraint(equalToConstant: view.frame.width).isActive = true
        textField.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        textfieldBottomAnchor = textField.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        textfieldBottomAnchor?.isActive = true

        setUpKeyBoardObservers()
    }
    //4 Use NSnotificationCenter to monitor the keyboard updates
    func setUpKeyBoardObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    //5 toggle the bottom layout global variable based on the keyboard's height
    func handleKeyboardWillShow(notification: NSNotification) {

        let keyboardFrame = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect
        if let keyboardFrame = keyboardFrame {
            textfieldBottomAnchor?.constant = -keyboardFrame.height
        }
        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
        if let keyboardDuration = keyboardDuration {
            UIView.animate(withDuration: keyboardDuration, animations: {
                self.view.layoutIfNeeded()
            })
        }
    }

    func handleKeyboardWillHide(notification: NSNotification) {

        textfieldBottomAnchor?.constant = 0
        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
        if let keyboardDuration = keyboardDuration {
            UIView.animate(withDuration: keyboardDuration, animations: {
                self.view.layoutIfNeeded()
            })
        }
    }
    //6 remove the observers
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)

        NotificationCenter.default.removeObserver(self)
    }
}