如何移动UITextField以响应iOS7中出现和消失的键盘？

Question

如何在屏幕上移动UITextField，使其不在iOS7中被键盘覆盖，然后在键盘被解除后将其返回到UIView内的原始位置？

Answer 1

在Viewcontroller.h

@interface ViewController : UIViewController<UITextFieldDelegate> 
{ 
CGFloat animatedDistance; 

} 

在ViewController.M

//粘贴任何地方低于4行上的类（的方法外）

static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3; 
static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2; 
static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8; 
static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 216; 

在委托方法是

-(void)textFieldDidBeginEditing:(UITextField *)textField 
{ 
    CGRect textFieldRect = 
[self.view.window convertRect:textField.bounds fromView:textField]; 
CGRect viewRect = 
[self.view.window convertRect:self.view.bounds fromView:self.view]; 

CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height; 
CGFloat numerator = 
midline - viewRect.origin.y 
- MINIMUM_SCROLL_FRACTION * viewRect.size.height; 
CGFloat denominator = 
(MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) 
* viewRect.size.height; 
CGFloat heightFraction = numerator/denominator; 
if (heightFraction < 0.0) 
{ 
    heightFraction = 0.0; 
} 
else if (heightFraction > 1.0) 
{ 
    heightFraction = 1.0; 
} 


animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction); 

CGRect viewFrame = self.view.frame; 
viewFrame.origin.y -= animatedDistance; 

[UIView beginAnimations:nil context:NULL]; 
[UIView setAnimationBeginsFromCurrentState:YES]; 
[UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION]; 

[self.view setFrame:viewFrame]; 

[UIView commitAnimations]; 
} 

- (void)textFieldDidEndEditing:(UITextField *)textField 

{ 
CGRect viewFrame = self.view.frame; 
viewFrame.origin.y += animatedDistance; 

[UIView beginAnimations:nil context:NULL]; 
[UIView setAnimationBeginsFromCurrentState:YES]; 
[UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION]; 

[self.view setFrame:viewFrame]; 

[UIView commitAnimations]; 

} 

Answer 2

你必须赶上UIKeyboardWillShowNotification的通知，并编辑你的帧以将UITextField移动到正确的位置（例如通过使用[UIView animateWithDuration：（NSTimeInterval）动画：^（void）动画]）。

这里是一个示例...

在init，在UIKeyboardWillShowNotification添加一个观察者：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow) name:UIKeyboardWillShowNotification object:nil]; 

然后添加- keyboardWillShow方法来更新您的视图（假设_textfield是你UITextField的名称） ：

- (void)keyboardWillShow { 
    NSLog(@"Show Keyboard"); 

    [UIView animateWithDuration:.2 animations:^{ 
     [_textField setFrame:_textField.frame]; 
     [_textField setFrame:CGRectMake(_textfield.frame.origin.x, _textfield.frame.origin.y - 240, _textfield.frame.size.width, _textfield.frame.size.height)]; 
    }]; 
} 

您可以使用UIKeyboardWillShowNotification通知n来执行反向操作。

Answer 3

我推荐使用UIScrollView将内容向上移动，当显示键盘时。 另请参阅Apple discourages us使用自定义常量的键盘大小：其他语言可能有不同的大小。正确的尺寸是嵌入在通知的用户信息：

获得通知键盘变化：

[[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(keyboardWillBeShown:) 
              name:UIKeyboardWillShowNotification object:nil]; 

[[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(keyboardWillBeHidden:) 
              name:UIKeyboardWillHideNotification object:nil]; 

记住清除观察者这样的：

-(void)dealloc { 
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 
} 

这些方法处理的键盘变化：

- (void)keyboardWillBeShown:(NSNotification*)aNotification 
{ 
    NSDictionary* info = [aNotification userInfo]; 
    CGRect kbRect = [self.view.window convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.scrollView]; 
    CGSize kbSize = kbRect.size; 

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0); 
    self.scrollView.contentInset = contentInsets; 
    self.scrollView.scrollIndicatorInsets = contentInsets; 
} 

- (void)keyboardWillBeHidden:(NSNotification*)aNotification 
{ 
    NSDictionary* info = [aNotification userInfo]; 
    NSTimeInterval duration = [info[UIKeyboardAnimationDurationUserInfoKey] doubleValue]; 
    [UIView animateWithDuration:duration animations:^{ 
     UIEdgeInsets contentInsets = UIEdgeInsetsZero; 
     self.scrollView.contentInset = contentInsets; 
     self.scrollView.scrollIndicatorInsets = contentInsets; 
    }]; 
} 

当然你也可以操作fra使用这些方法的UITextView的我。