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。
我在这里没有看到这种可能性，所以我添加了它，因为我尝试了答案中的方法，但几个小时后发现在iOS6/7中的XCode 5中有一种更简单的方法：使用NSLayoutConstraints。
请参见：自动布局约束-键盘
这是我的代码：
.m文件：
// Called when the UIKeyboardWillShowNotification is sent.
- (void)keyboardWillBeShown:(NSNotification*)aNotification
{
NSLog(@"keyboardWillBeShown:");
[self.PhoneNumberLabelOutlet setHidden:TRUE];
CGFloat heightOfLabel = self.PhoneNumberLabelOutlet.frame.size.height;
for( NSLayoutConstraint* thisConstraint in self.topElementsVerticalDistanceFromTopLayoutConstraint ) {
thisConstraint.constant -= heightOfLabel;
}
NSDictionary* info = [aNotification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
CGFloat oldConstant = [self.SignInYConstraint constant];
self.SignInYConstraint.constant = oldConstant + kbSize.height;
[self.view setNeedsUpdateConstraints];
NSTimeInterval duration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
[UIView animateWithDuration:duration animations:^{
[self.view layoutIfNeeded];
}];
}
.h文件：
#import <UIKit/UIKit.h>
@interface SignInViewController : UIViewController {
UITextField* _activeField;
}
- (void)signInCallback:(NSObject*)object;
@property (weak, nonatomic) IBOutlet UILabel *PhoneNumberLabelOutlet;
@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *ActivityIndicatorOutlet;
@property (weak, nonatomic) IBOutlet UITextField *UserIDTextfieldOutlet;
@property (weak, nonatomic) IBOutlet UITextField *PasswordTextfieldOutlet;
@property (weak, nonatomic) IBOutlet UIButton *SignInButton;
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *SignInYConstraint;
@property (strong, nonatomic) IBOutletCollection(NSLayoutConstraint) NSArray *topElementsVerticalDistanceFromTopLayoutConstraint;
@end
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。
有很多答案可以告诉我们这个方法。我采取了相同的方法，但实施效果不佳。
这是基本想法。我修改了keyboardWasShown方法。
{
// Obtain keyboard Info
NSDictionary* info = [notification userInfo];
CGRect keyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
// Obtain ScrollView Info w.r.t. top View
CGRect scrollViewRect = [self.view convertRect:self.scrollView.frame fromView:nil];
// Depending upon your screen Ui, Scroll View's bottom edge might be at some offset from screen's bottom
// Calculate the exact offset
int scrollViewBottomOffset = self.view.frame.size.height - (scrollViewRect.origin.y + scrollViewRect.size.height);
int heightToBeAdjusted = keyboardRect.size.height - scrollViewBottomOffset;
// We may also need to consider the Insets if already present with ScrollView. Let's keep it simple for now
// But we should store these, so that we can restore the Insets when Keyboard is gone
// origInsets = self.scrollView.contentInset;
// Set the new Insets for ScrollView
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, heightToBeAdjusted, 0.0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;
// Visible frame (not overlapped by Keyboard)
CGRect visibleFrame = self.view.frame;
visibleFrame.size.height -= keyboardRect.size.height;
// Get the Rect for Textfield w.r.t self.view
CGRect activeFieldFrame = self.activeField.frame;
activeFieldFrame = [self.view convertRect:activeFieldFrame fromView:self.scrollView];
// Check if the TextField is Visible or not
if (!CGRectContainsRect(visibleFrame, activeFieldFrame) ) {
// Scroll to make it visible but for scrolling use the activeField frame w.r.t. to scroll View
[self.scrollView scrollRectToVisible:self.activeField.frame animated:YES];
}
}
并添加此方法来初始化activeField
- (IBAction)textFieldDidBeginEditing:(UITextField *)sender
{
self.activeField = sender;
}
