使用 iOS SDK：
我有一个带UITextField的UIView ， UITextField一个键盘。我需要它能够：
在键盘启动后，允许滚动UIScrollView的内容以查看其他文本字段
自动 “跳跃”（通过向上滚动）或缩短
我知道我需要一个UIScrollView 。我已经尝试将我的UIView的类更改为UIScrollView但我仍然无法向上或向下滚动文本框。
我是否需要UIView和UIScrollView ？一个人进去另一个吗？
需要实现什么才能自动滚动到活动文本字段？
理想情况下，尽可能多的组件设置将在 Interface Builder 中完成。我只想编写需要它的代码。
注意：我正在使用的UIView （或UIScrollView ）是由 tabbar（ UITabBar ）启动的，它需要正常运行。
编辑：我正在添加滚动条，仅用于键盘出现时。即使它不需要，我觉得它提供了更好的界面，因为用户可以滚动和更改文本框。
当键盘上下移动时我改变了UIScrollView的框架大小。我只是用：
-(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
}但是，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。
如果您现在拥有的内容不适合 iPhone 屏幕，则只需要ScrollView 。 （如果要将ScrollView添加为组件的超级视图。只是为了在键盘出现时向上滚动TextField ，那么就不需要了。）
为了显示textfields而不被键盘隐藏，标准方法是在显示键盘时向上 / 向下移动具有文本字段的视图。
以下是一些示例代码：
#define kOFFSET_FOR_KEYBOARD 80.0
-(void)keyboardWillShow {
// Animate the current view out of the way
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}
-(void)keyboardWillHide {
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
else if (self.view.frame.origin.y < 0)
{
[self setViewMovedUp:NO];
}
}
-(void)textFieldDidBeginEditing:(UITextField *)sender
{
if ([sender isEqual:mailTf])
{
//move the main view, so that the keyboard does not hide it.
if (self.view.frame.origin.y >= 0)
{
[self setViewMovedUp:YES];
}
}
}
//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3]; // if you want to slide up the view
CGRect rect = self.view.frame;
if (movedUp)
{
// 1. move the view's origin up so that the text field that will be hidden come above the keyboard
// 2. increase the size of the view so that the area behind the keyboard is covered up.
rect.origin.y -= kOFFSET_FOR_KEYBOARD;
rect.size.height += kOFFSET_FOR_KEYBOARD;
}
else
{
// revert back to the normal state.
rect.origin.y += kOFFSET_FOR_KEYBOARD;
rect.size.height -= kOFFSET_FOR_KEYBOARD;
}
self.view.frame = rect;
[UIView commitAnimations];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
// register for keyboard notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide)
name:UIKeyboardWillHideNotification
object:nil];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// unregister for keyboard notifications while not visible.
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillHideNotification
object:nil];
}我在编写多个UITextFields的UIScrollView遇到了很多问题，其中一个或多个UITextFields在编辑时会被键盘遮挡。
如果您的UIScrollView没有正确滚动，请考虑以下事项。
1）确保您的 contentSize 大于UIScrollView框架大小。理解UIScrollViews的方法是UIScrollView就像是在 contentSize 中定义的内容上的查看窗口。因此，为了使UIScrollview能够在任何地方滚动，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）现在您已经了解UIScrollView实际上是 “内容” 的窗口，确保键盘不会遮挡UIScrollView's查看 “窗口” 的方法是调整UIScrollView大小，以便在键盘存在时，将UIScrollView窗口的大小设置为原始的UIScrollView frame.size.height 减去键盘的高度。这将确保您的窗口只是那个小的可视区域。
3）这里有一个问题：当我第一次实现这个时，我想我必须得到已编辑文本字段的CGRect并调用UIScrollView's scrollRecToVisible 方法。我通过调用scrollRecToVisible方法实现了UITextFieldDelegate方法textFieldDidBeginEditing 。这实际上有一个奇怪的副作用，滚动会将UITextField 捕捉到位。在最长的时间里，我无法弄清楚它是什么。然后我注释掉了textFieldDidBeginEditing Delegate 方法，它一切正常!!（???）。事实证明，我相信UIScrollView实际上隐式地将当前编辑的UITextField隐藏到可查看窗口中。我对UITextFieldDelegate方法的实现和随后对scrollRecToVisible调用是多余的，并且是导致奇怪副作用的原因。
因此，以下是在键盘出现时将UIScrollView的UITextField正确滚动到位的步骤。
// 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;
}viewDidLoad注册键盘通知viewDidUnload的键盘 nofitications viewDidLoad设置了contentSize并且大于UIScrollView UIScrollView UIScrollView 。 UITextField都有标签时发送键盘通知，即使键盘已经存在，以避免在UIScrollView已经缩小时缩小 UIScrollView 需要注意的一点是，当您在另一个UITextField上进行选项卡时，即使键盘已经在屏幕上， UIKeyboardWillShowNotification也会触发。我通过使用 ivar 来解决这个问题，以避免在键盘已经在屏幕上时调整UIScrollView大小。当键盘已经存在时无意中调整UIScrollView大小将是灾难性的！
希望这段代码可以让你们中的一些人头疼。
实际上，最好只使用 Apple 的实现，如文档中所提供的那样。但是，他们提供的代码是错误的。替换在keyboardWasShown:找到的部分keyboardWasShown:在注释的正下方以下内容：
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];
} Apple 代码的问题是这些：（1）它们总是计算点是否在视图的框架内，但它是ScrollView ，因此它可能已经滚动，您需要考虑该偏移：
origin.y -= scrollView.contentOffset.y （2）他们将 contentOffset 移动键盘的高度，但我们想要相反（我们希望将contentOffset移动到屏幕上可见的高度，而不是不是）：
activeField.frame.origin.y-(aRect.size.height)