键盘遮挡textfield方案

- (void)keyboardWasShown:(NSNotification *)noti {
    NSDictionary *info = noti.userInfo;
    UITextField *activeField = noti.object;
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0, 0, kbSize.height, 0);
    self.originInset = self.scrollView.contentInset;
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;

    CGRect aRect = self.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, activeField.frame.origin)) {
        CGPoint scrollPoint = CGPointMake(0, activeField.frame.origin.y - kbSize.height);
        [self.scrollView setContentOffset:scrollPoint animated:YES];
    }
}

- (void)keyboardWillBeHidden:(NSNotification *)noti {
    UIEdgeInsets contentInsets = self.originInset;
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;
}