iOS——获取键盘高度，

- (void)viewDidLoad
{
    [super viewDidLoad];

    //使用NSNotificationCenter 键盘出现时
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWasShown:)
                                                 name:UIKeyboardWillShowNotification object:nil];
    
    //使用NSNotificationCenter 键盘隐藏时
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification object:nil];
    
    [self reloadBusLine];

}

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

- (void)keyboardWillShow:(NSNotification *)notification 
{

    NSDictionary *userInfo = [notification userInfo];
    
    NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect = [aValue CGRectValue];
    keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
    
    CGFloat keyboardTop = keyboardRect.origin.y;
    CGRect newTextViewFrame = self.view.bounds;
    newTextViewFrame.size.height = keyboardTop - self.view.bounds.origin.y;
    
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];
    
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:animationDuration];
    
    textView.frame = newTextViewFrame;

    [UIView commitAnimations];
}

- (void)keyboardWillHide:(NSNotification *)notification 
{
    
    NSDictionary* userInfo = [notification userInfo];
    
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];
    
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:animationDuration];
    
    textView.frame = self.view.bounds;
    
    [UIView commitAnimations];
}