UIKeyboardWillShowNotification

UIKeyboardWillShowNotification 通知来获得当键盘改变时，该键盘的高度和位置。 
然后调整自己相应的UI元素位置即可，示例代码如下： 
 
 
-(void)viewDidLoad{ 
   [superviewDidLoad]; 
   [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil]; 
} 
-(void)viewDidUnload{ 
   [superviewDidUnload]; 
   [[NSNotificationCenter defaultCenter]removeObserver:self]; 
} 
-(void)keyboardWillShow:(NSNotification*)notification{ 
   NSDictionary*info=[notification userInfo]; 
   CGSize kbSize=[[info objectForKey:UIKeyboardFrameEndUserInfoKey]CGRectValue].size; 
   NSLog(@"keyboard changed, keyboard width = %f, height = %f",  
          kbSize.width,kbSize.height); 
   //在这里调整UI位置 
}