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。
一个更为优雅的解决方案是使用UIView子类（虽然这并不总是合适的），并在父帧更改时重新计算所有子视图（并且要聪明：只有在新帧大小发生更改时才重新计算它们，即在重写setFrame和调用[super setFrame:frame_]之前使用CGRectEqualToRect来比较新帧）。唯一的缺点是，您打算使用的UIViewController可能应该监听键盘事件（或者，您可以在UIView本身中进行监听，以方便封装）。但只有UIKeyboardWillShowNotification和UIKeyboard WillHideNotification。这只是为了让它看起来平滑（如果你等待CG调用它，你会得到一个波涛汹涌的时刻）。
无论如何，这有一个优点，那就是构建一个做正确事情的UIView子类。
天真的实现是重写drawRect:（不要），更好的方法是只使用layoutSubviews（然后在UIViewController中，或者在为显示或隐藏调用的SINGLE方法中调用[view setNeedsLayout]）。
此解决方案摆脱了硬编码键盘偏移（如果它们不在拆分等中，则会发生变化），还意味着您的视图可以是许多其他视图的子视图，并且仍然可以正确响应。
除非没有其他解决方案，否则不要硬编码这样的东西。如果你做得对，操作系统会给你足够的信息，你只需要智能地重新绘制（基于你的新帧大小）。这要干净得多，而且是你应该做的事情。（不过，可能还有更好的方法。）
干杯
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
}
}
有很多答案可以告诉我们这个方法。我采取了相同的方法，但实施效果不佳。
这是基本想法。我修改了keyboardWasShown方法。
{
// Obtain keyboard Info
NSDictionary* info = [notification userInfo];
CGRect keyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
// Obtain ScrollView Info w.r.t. top View
CGRect scrollViewRect = [self.view convertRect:self.scrollView.frame fromView:nil];
// Depending upon your screen Ui, Scroll View's bottom edge might be at some offset from screen's bottom
// Calculate the exact offset
int scrollViewBottomOffset = self.view.frame.size.height - (scrollViewRect.origin.y + scrollViewRect.size.height);
int heightToBeAdjusted = keyboardRect.size.height - scrollViewBottomOffset;
// We may also need to consider the Insets if already present with ScrollView. Let's keep it simple for now
// But we should store these, so that we can restore the Insets when Keyboard is gone
// origInsets = self.scrollView.contentInset;
// Set the new Insets for ScrollView
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, heightToBeAdjusted, 0.0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;
// Visible frame (not overlapped by Keyboard)
CGRect visibleFrame = self.view.frame;
visibleFrame.size.height -= keyboardRect.size.height;
// Get the Rect for Textfield w.r.t self.view
CGRect activeFieldFrame = self.activeField.frame;
activeFieldFrame = [self.view convertRect:activeFieldFrame fromView:self.scrollView];
// Check if the TextField is Visible or not
if (!CGRectContainsRect(visibleFrame, activeFieldFrame) ) {
// Scroll to make it visible but for scrolling use the activeField frame w.r.t. to scroll View
[self.scrollView scrollRectToVisible:self.activeField.frame animated:YES];
}
}
并添加此方法来初始化activeField
- (IBAction)textFieldDidBeginEditing:(UITextField *)sender
{
self.activeField = sender;
}
如果文本字段未完全或部分隐藏，则我们不应更改任何内容。我们应该计算隐藏的精确相交区域（键盘的框架和文本字段的框架），然后我们应该更改视图的框架。这里我给出了一个完整的例子。声明3个变量
#定义衬垫10@接口PKViewController（）@属性（非原子，赋值）CGRect-originalViewFrame//原始视图的框架@属性（非原子，强）UITextField*activeTextField；//当前文本字段@属性（非原子，赋值）CGRect keyBoardRect；//安全板覆盖面积@完
存储原始帧
- (void)viewDidLoad {
[super viewDidLoad];
_originalViewFrame = self.view.frame;
}
将视图控制器添加为键盘通知的观察者
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWasShown:)
name:UIKeyboardDidShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
}
移除观察者
- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
当键盘出现时存储键盘覆盖的区域，当键盘消失时将其设置为CGRectZero
- (void)keyboardWasShown:(NSNotification *)notification{
CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
_keyBoardRect = CGRectMake(0, _originalViewFrame.size.height - keyboardSize.height, keyboardSize.width, keyboardSize.height);
[self moveTextFieldUP];
}
- (void) keyboardWillHide:(NSNotification *)notification{
_keyBoardRect = CGRectZero;
[self setDefaultFrame];
}
存储活动文本字段
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
_activeTextField = textField;
//When keyboard is already present but the textfield is hidden. Case:When return key of keyboard makes the next textfield as first responder
if (!CGRectIsEmpty(_keyBoardRect)) {
[self moveTextFieldUP];
}
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
[textField resignFirstResponder];
return YES;
}
现在我们应该改变视图的框架
- (void)moveTextFieldUP{
CGRect virtualTextFieldRect = CGRectMake(0, self.view.frame.origin.y, _activeTextField.frame.size.width, _activeTextField.frame.origin.y+_activeTextField.frame.size.height);
if (CGRectIntersectsRect(_keyBoardRect, virtualTextFieldRect)) {
CGRect intersectRect = CGRectIntersection(_keyBoardRect, virtualTextFieldRect);
CGFloat newY = _originalViewFrame.origin.y - intersectRect.size.height;
CGFloat newHeight = _originalViewFrame.size.height + intersectRect.size.height;
CGRect newFrame = CGRectMake(0, newY-PADDING, _originalViewFrame.size.width, newHeight+PADDING);
[UIView animateWithDuration:0.3 animations:^{
[self.view setFrame:newFrame];
}];
NSLog(@"Intersect");
}
}
- (void)setDefaultFrame {
[UIView animateWithDuration:0.3 animations:^{
[self.view setFrame:_originalViewFrame];
}];
}
