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。
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];
}];
}
我发现这是最好的解决方案，请遵循以下代码：
将以下内容附加到垂直空间-底部布局指南-文本字段约束。
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *textViewBottomConst;
第二，为键盘通知添加观察员。
- (void)observeKeyboard {
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}
将此添加到您的视图DidLoad
[self observeKeyboard];
最后，处理键盘更改的方法。
- (void)keyboardWillShow:(NSNotification *)notification {
//THIS WILL MAKE SURE KEYBOARD DOESNT JUMP WHEN OPENING QUICKTYPE/EMOJI OR OTHER KEYBOARDS.
kbHeight = 0;
height = 0;
self.textViewBottomConst.constant = height;
self.btnViewBottomConst.constant = height;
NSDictionary *info = [notification userInfo];
NSValue *kbFrame = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
NSTimeInterval animationDuration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
CGRect keyboardFrame = [kbFrame CGRectValue];
CGRect finalKeyboardFrame = [self.view convertRect:keyboardFrame fromView:self.view.window];
int kbHeight = finalKeyboardFrame.size.height;
int height = kbHeight + self.textViewBottomConst.constant;
self.textViewBottomConst.constant = height;
[UIView animateWithDuration:animationDuration animations:^{
[self.view layoutIfNeeded];
}];
}
- (void)keyboardWillHide:(NSNotification *)notification {
NSDictionary *info = [notification userInfo];
NSTimeInterval animationDuration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
self.textViewBottomConst.constant = 10;
[UIView animateWithDuration:animationDuration animations:^{
[self.view layoutIfNeeded];
}];
}
实际上，最好只使用苹果的实现，正如文档中所提供的那样。然而，他们提供的代码是错误的。将keyboardWasShow:注释下方的部分替换为以下内容：
NSDictionary* info = [aNotification userInfo];
CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];
CGSize kbSize =keyPadFrame.size;
CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];
CGRect aRect = self.view.bounds;
aRect.size.height -= (kbSize.height);
CGPoint origin = activeRect.origin;
origin.y -= backScrollView.contentOffset.y;
if (!CGRectContainsPoint(aRect, origin)) {
CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));
[backScrollView setContentOffset:scrollPoint animated:YES];
}
苹果代码存在以下问题：（1） 他们总是计算该点是否在视图的框架内，但它是一个ScrollView，因此它可能已经滚动，您需要考虑该偏移：
origin.y -= scrollView.contentOffset.y
（2） 他们按键盘的高度移动contentOffset，但我们希望相反（我们希望按屏幕上可见的高度而不是不可见的高度移动contentOffset）：
activeField.frame.origin.y-(aRect.size.height)
