iOS获取系统键盘的高度

1. NSNotificationCenter *defaultCenter = [NSNotificationCenter defaultCenter];  
2.     //UIKeyboardWillShowNotification键盘出现  
3.     [defaultCenter addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];  
4.   
5.     //UIKeyboardWillHideNotification 键盘隐藏  
6.     [defaultCenter addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];  
7.   
8. - (void)keyboardWillShow:(NSNotification *)aNotification  
9. {  
10.     //获取键盘的高度  
11.     NSDictionary *userInfo = [aNotification userInfo];  
12.     NSValue *aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];  
13.     CGRect keyboardRect = [aValue CGRectValue];  
14.     int height = keyboardRect.size.width;  
15. }