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。
已经有很多答案了,但上面的解决方案仍然没有一个具备“完美”无bug、向后兼容和无闪烁动画所需的所有花哨定位功能。(在一起设置帧/边界和contentOffset动画时出错,界面方向不同,iPad分割键盘等)让我分享我的解决方案:(假设您已设置UIKeyboardWill(显示|隐藏)通知)
// Called when UIKeyboardWillShowNotification is sent
- (void)keyboardWillShow:(NSNotification*)notification
{
// if we have no view or are not visible in any window, we don't care
if (!self.isViewLoaded || !self.view.window) {
return;
}
NSDictionary *userInfo = [notification userInfo];
CGRect keyboardFrameInWindow;
[[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardFrameInWindow];
// the keyboard frame is specified in window-level coordinates. this calculates the frame as if it were a subview of our view, making it a sibling of the scroll view
CGRect keyboardFrameInView = [self.view convertRect:keyboardFrameInWindow fromView:nil];
CGRect scrollViewKeyboardIntersection = CGRectIntersection(_scrollView.frame, keyboardFrameInView);
UIEdgeInsets newContentInsets = UIEdgeInsetsMake(0, 0, scrollViewKeyboardIntersection.size.height, 0);
// this is an old animation method, but the only one that retains compaitiblity between parameters (duration, curve) and the values contained in the userInfo-Dictionary.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];
[UIView setAnimationCurve:[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
_scrollView.contentInset = newContentInsets;
_scrollView.scrollIndicatorInsets = newContentInsets;
/*
* Depending on visual layout, _focusedControl should either be the input field (UITextField,..) or another element
* that should be visible, e.g. a purchase button below an amount text field
* it makes sense to set _focusedControl in delegates like -textFieldShouldBeginEditing: if you have multiple input fields
*/
if (_focusedControl) {
CGRect controlFrameInScrollView = [_scrollView convertRect:_focusedControl.bounds fromView:_focusedControl]; // if the control is a deep in the hierarchy below the scroll view, this will calculate the frame as if it were a direct subview
controlFrameInScrollView = CGRectInset(controlFrameInScrollView, 0, -10); // replace 10 with any nice visual offset between control and keyboard or control and top of the scroll view.
CGFloat controlVisualOffsetToTopOfScrollview = controlFrameInScrollView.origin.y - _scrollView.contentOffset.y;
CGFloat controlVisualBottom = controlVisualOffsetToTopOfScrollview + controlFrameInScrollView.size.height;
// this is the visible part of the scroll view that is not hidden by the keyboard
CGFloat scrollViewVisibleHeight = _scrollView.frame.size.height - scrollViewKeyboardIntersection.size.height;
if (controlVisualBottom > scrollViewVisibleHeight) { // check if the keyboard will hide the control in question
// scroll up until the control is in place
CGPoint newContentOffset = _scrollView.contentOffset;
newContentOffset.y += (controlVisualBottom - scrollViewVisibleHeight);
// make sure we don't set an impossible offset caused by the "nice visual offset"
// if a control is at the bottom of the scroll view, it will end up just above the keyboard to eliminate scrolling inconsistencies
newContentOffset.y = MIN(newContentOffset.y, _scrollView.contentSize.height - scrollViewVisibleHeight);
[_scrollView setContentOffset:newContentOffset animated:NO]; // animated:NO because we have created our own animation context around this code
} else if (controlFrameInScrollView.origin.y < _scrollView.contentOffset.y) {
// if the control is not fully visible, make it so (useful if the user taps on a partially visible input field
CGPoint newContentOffset = _scrollView.contentOffset;
newContentOffset.y = controlFrameInScrollView.origin.y;
[_scrollView setContentOffset:newContentOffset animated:NO]; // animated:NO because we have created our own animation context around this code
}
}
[UIView commitAnimations];
}
// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillHide:(NSNotification*)notification
{
// if we have no view or are not visible in any window, we don't care
if (!self.isViewLoaded || !self.view.window) {
return;
}
NSDictionary *userInfo = notification.userInfo;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:[[userInfo valueForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];
[UIView setAnimationCurve:[[userInfo valueForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
// undo all that keyboardWillShow-magic
// the scroll view will adjust its contentOffset apropriately
_scrollView.contentInset = UIEdgeInsetsZero;
_scrollView.scrollIndicatorInsets = UIEdgeInsetsZero;
[UIView commitAnimations];
}
下面是带有文本字段的滚动视图的简单解决方案,不需要任何约束或活动文本字段等。。。
override func viewWillAppear(_ animated: Bool){
super.viewWillAppear(animated)
registerForKeyboardNotifications();
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
deregisterFromKeyboardNotifications();
}
//MARK:- KEYBOARD DELEGATE METHODS
func registerForKeyboardNotifications(){
//Adding notifies on keyboard appearing
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func deregisterFromKeyboardNotifications(){
//Removing notifies on keyboard appearing
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWasShown(notification: NSNotification){
var info = notification.userInfo!
let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
var contentInset:UIEdgeInsets = self.scrRegister.contentInset
contentInset.bottom = (keyboardSize?.height)!
scrRegister.contentInset = contentInset
}
func keyboardWillBeHidden(notification: NSNotification)
{
var contentInset:UIEdgeInsets = self.scrRegister.contentInset
contentInset.bottom = 0
scrRegister.contentInset = contentInset
}
我对UIScrollView由多个UITextField组成也有很多问题,其中一个或多个在编辑时会被键盘遮挡。
如果UIScrollView滚动不正确,请考虑以下几点。
1) 确保contentSize大于UIScrollView框架大小。理解UIScrollViews的方法是UIScrollView就像一个查看contentSize中定义的内容的窗口。因此,如果要让UIScrollview滚动到任何位置,contentSize必须大于UIScrollview。否则,不需要滚动,因为contentSize中定义的所有内容都已可见。BTW,默认contentSize=CGSizeZero。
2) 既然您已经了解到UIScrollView实际上是一个“内容”窗口,那么确保键盘不会遮挡UIScroll View的查看“窗口”的方法就是调整UIScrollView的大小,这样当键盘出现时,UIScrollView窗口的大小就等于UIScrollviewframe.size.height减去键盘的高度。这将确保您的窗口仅是那个小的可视区域。
3) 这里有一个陷阱:当我第一次实现这一点时,我想我必须获得编辑文本字段的CGRect,并调用UIScrollView的scrollRecToVisible方法。我通过调用scrollRecToVisible方法实现了UITextFieldDelegate方法textFieldDidBeginEditing。这实际上产生了一个奇怪的副作用,即滚动会将UITextField捕捉到位。在很长一段时间里,我都搞不清那是什么。然后我注释了textFieldDidBegginEditingDelegate方法,这一切都奏效了!!(???). 事实证明,我相信UIScrollView实际上隐式地将当前编辑的UITextField带入可视窗口。我对UITextFieldDelegate方法的实现以及随后对scrollRecToVisible的调用是多余的,这是产生奇怪副作用的原因。
因此,当键盘出现时,以下是在UIScrollView中正确滚动UITextField的步骤。
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
[super viewDidLoad];
// register for keyboard notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:self.view.window];
// register for keyboard notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:self.view.window];
keyboardIsShown = NO;
//make contentSize bigger than your scrollSize (you will need to figure out for your own use case)
CGSize scrollContentSize = CGSizeMake(320, 345);
self.scrollView.contentSize = scrollContentSize;
}
- (void)keyboardWillHide:(NSNotification *)n
{
NSDictionary* userInfo = [n userInfo];
// get the size of the keyboard
CGSize keyboardSize = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
// resize the scrollview
CGRect viewFrame = self.scrollView.frame;
// I'm also subtracting a constant kTabBarHeight because my UIScrollView was offset by the UITabBar so really only the portion of the keyboard that is leftover pass the UITabBar is obscuring my UIScrollView.
viewFrame.size.height += (keyboardSize.height - kTabBarHeight);
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[self.scrollView setFrame:viewFrame];
[UIView commitAnimations];
keyboardIsShown = NO;
}
- (void)keyboardWillShow:(NSNotification *)n
{
// This is an ivar I'm using to ensure that we do not do the frame size adjustment on the `UIScrollView` if the keyboard is already shown. This can happen if the user, after fixing editing a `UITextField`, scrolls the resized `UIScrollView` to another `UITextField` and attempts to edit the next `UITextField`. If we were to resize the `UIScrollView` again, it would be disastrous. NOTE: The keyboard notification will fire even when the keyboard is already shown.
if (keyboardIsShown) {
return;
}
NSDictionary* userInfo = [n userInfo];
// get the size of the keyboard
CGSize keyboardSize = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
// resize the noteView
CGRect viewFrame = self.scrollView.frame;
// I'm also subtracting a constant kTabBarHeight because my UIScrollView was offset by the UITabBar so really only the portion of the keyboard that is leftover pass the UITabBar is obscuring my UIScrollView.
viewFrame.size.height -= (keyboardSize.height - kTabBarHeight);
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[self.scrollView setFrame:viewFrame];
[UIView commitAnimations];
keyboardIsShown = YES;
}
在viewDidLoad上注册键盘通知在viewDidUnload中注销键盘nofitions确保contentSize设置为大于UIScrollView at viewDidLoad当有键盘时,缩小UIScrollView当键盘离开时,恢复UIScrollView。使用ivar来检测键盘是否已经显示在屏幕上,因为每次UITextField选项卡时都会发送键盘通知,即使键盘已经存在,以避免在UIScrollView已经缩小时缩小它
需要注意的一点是,当您单击另一个UITextField时,即使键盘已经在屏幕上,UIKeyboardWillShowNotification也会启动。当键盘已经在屏幕上时,我使用ivar来避免调整UIScrollView的大小。当键盘已经存在时,不小心调整UIScrollView的大小将是灾难性的!
希望这段代码能让你们中的一些人省去很多麻烦。
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
}
}