-(void)viewDidLoad {NSNotificationCenter *center = [NSNotificationCenter defaultCenter];        //注册键盘显示通知    [center addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];    //注册键盘隐藏通知    [center addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];}-(void)viewDidDisappear:(BOOL)animated{    //移除通知    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];}- (void) keyboardWillShow:(NSNotification *) notification{        NSDictionary *info;    CGSize kbSize;    double kbheight;    CGFloat Oversize;    double duraction;        info = notification.userInfo;    kbSize = [[info objectForKey: UIKeyboardFrameEndUserInfoKey]CGRectValue].size;    kbheight = kbSize.height;        Oversize = (self.view.frame.size.height - kbheight) - (textfield.frame.origin.y + textfield.frame.size.height+5);        duraction =  [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];        if (Oversize < 0){        [UIView animateWithDuration: duraction animations:^{            self.view.frame = CGRectMake(0.0f, Oversize, self.view.frame.size.width, self.view.frame.size.height);        }];    }}-(void) keyboardWillHide:(NSNotification *) notification{        double duraction = [[notification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];        [UIView animateWithDuration:duraction animations:^{        self.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);    }];}