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。
这是我为特定布局想出的破解方案。此解决方案与Matt Gallagher的解决方案相似，即将一个部分滚动到视图中。我还是iPhone开发的新手，不熟悉布局的工作原理。因此，这个黑客。
我的实现需要支持在字段中单击时滚动，以及用户在键盘上选择下一个时滚动。
我有一个UIView，身高775。控件基本上以3人一组的方式分布在一个大的空间中。我最终得到了以下IB布局。
UIView -> UIScrollView -> [UI Components]
黑客来了
我将UIScrollView的高度设置为比实际布局（1250）大500个单位。然后，我创建了一个数组，其中包含我需要滚动到的绝对位置，以及一个基于IB标记号获取它们的简单函数。
static NSInteger stepRange[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 140, 140, 140, 140, 140, 410
};
NSInteger getScrollPos(NSInteger i) {
if (i < TXT_FIELD_INDEX_MIN || i > TXT_FIELD_INDEX_MAX) {
return 0 ;
return stepRange[i] ;
}
现在，您需要做的就是在textFieldDidBeginEditing和textFieldShouldReturn中使用以下两行代码（如果要创建下一个字段导航，则使用后者）
CGPoint point = CGPointMake(0, getScrollPos(textField.tag)) ;
[self.scrollView setContentOffset:point animated:YES] ;
一个例子。
- (void) textFieldDidBeginEditing:(UITextField *)textField
{
CGPoint point = CGPointMake(0, getScrollPos(textField.tag)) ;
[self.scrollView setContentOffset:point animated:YES] ;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
NSInteger nextTag = textField.tag + 1;
UIResponder* nextResponder = [textField.superview viewWithTag:nextTag];
if (nextResponder) {
[nextResponder becomeFirstResponder];
CGPoint point = CGPointMake(0, getScrollPos(nextTag)) ;
[self.scrollView setContentOffset:point animated:YES] ;
}
else{
[textField resignFirstResponder];
}
return YES ;
}
此方法不像其他方法那样“向后滚动”。这不是必需的。同样，这是一个相当“高大”的UIView，我没有时间学习内部布局引擎。
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)
}
}
在这里，我找到了处理键盘的最简单的解决方案。
您只需复制粘贴到示例代码下面，然后更改文本字段或任何要向上移动的视图。
步骤-1
只需在控制器中复制粘贴以下两种方法
- (void)registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:)
name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillBeHidden:)
name:UIKeyboardWillHideNotification object:nil];
}
- (void)deregisterFromKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidHideNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
步骤-2
在视图中注册和注销键盘通知WillAppear和viewWillDisappear方法。
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self registerForKeyboardNotifications];
}
- (void)viewWillDisappear:(BOOL)animated
{
[self deregisterFromKeyboardNotifications];
[super viewWillDisappear:animated];
}
步骤-3
灵魂部分来了，只要替换你的文本字段，然后改变高度你想向上移动多少。
- (void)keyboardWasShown:(NSNotification *)notification
{
NSDictionary* info = [notification userInfo];
CGSize currentKeyboardSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
//you need replace your textfield instance here
CGPoint textFieldOrigin = self.tokenForPlaceField.frame.origin;
CGFloat textFieldHeight = self.tokenForPlaceField.frame.size.height;
CGRect visibleRect = self.view.frame;
visibleRect.size.height -= currentKeyboardSize.height;
if (!CGRectContainsPoint(visibleRect, textFieldOrigin))
{
//you can add yor desired height how much you want move keypad up, by replacing "textFieldHeight" below
CGPoint scrollPoint = CGPointMake(0.0, textFieldOrigin.y - visibleRect.size.height + textFieldHeight); //replace textFieldHeight to currentKeyboardSize.height, if you want to move up with more height
[self.scrollView setContentOffset:scrollPoint animated:YES];
}
}
- (void)keyboardWillBeHidden:(NSNotification *)notification
{
[self.scrollView setContentOffset:CGPointZero animated:YES];
}
参考：好吧，请感谢这位分享了这个漂亮的代码片段、干净的解决方案的人。
希望这对外面的人会很有帮助。
