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。
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)
}
}
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)
}
}
我迟到了一点。您应该在viewController上添加scrollView。
您必须实现以下2种方法。
TextField委托方法。
- (void)textFieldDidBeginEditing:(UIView *)textField {
[self scrollViewForTextField:reEnterPINTextField];
}
然后在委托方法中调用以下方法。
- (void)scrollViewForTextField:(UIView *)textField {
NSInteger keyboardHeight = KEYBOARD_HEIGHT;
if ([textField UITextField.class]) {
keyboardHeight += ((UITextField *)textField).keyboardControl.activeField.inputAccessoryView.frame.size.height;
}
CGRect screenFrame = [UIScreen mainScreen].bounds;
CGRect aRect = (CGRect){0, 0, screenFrame.size.width, screenFrame.size.height - ([UIApplication sharedApplication].statusBarHidden ? 0 : [UIApplication sharedApplication].statusBarFrame.size.height)};
aRect.size.height -= keyboardHeight;
CGPoint relativeOrigin = [UIView getOriginRelativeToScreenBounds:textField];
CGPoint bottomPointOfTextField = CGPointMake(relativeOrigin.x, relativeOrigin.y + textField.frame.size.height);
if (!CGRectContainsPoint(aRect, bottomPointOfTextField) ) {
CGPoint scrollPoint = CGPointMake(0.0, bottomPointOfTextField.y -aRect.size.height);
[contentSlidingView setContentOffset:scrollPoint animated:YES];
}
}
