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。
在textFieldDidBginEditing和textFieldDidEndEditing中调用函数[self-animateTextField:textField up:YES]，如下所示：
-(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 = -130; // tweak as needed
const float movementDuration = 0.3f; // tweak as needed
int movement = (up ? movementDistance : -movementDistance);
[UIView beginAnimations: @"animateTextField" context: nil];
[UIView setAnimationBeginsFromCurrentState: YES];
[UIView setAnimationDuration: movementDuration];
self.view.frame = CGRectOffset(self.view.frame, 0, movement);
[UIView commitAnimations];
}
我希望这段代码对你有所帮助。
雨燕5
func animateTextField(textField: UITextField, up: Bool) {
let movementDistance: CGFloat = -130
let movementDuration: Double = 0.3
var movement:CGFloat = 0
if up {
movement = movementDistance
} else {
movement = -movementDistance
}
UIView.animate(withDuration: movementDuration, delay: 0, options: [.beginFromCurrentState]) {
self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)
}
}
func textFieldDidBeginEditing(_ textField: UITextField) {
animateTextField(textField: textField, up: true)
}
func textFieldDidEndEditing(_ textField: UITextField) {
animateTextField(textField: textField, up: false)
}
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];
}
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)
}
}
