iOS 第三方键盘多次回调处理

//            // 第三方键盘回调三次问题，监听仅执行最后一次
//            CGRect begin = [[[notification userInfo] objectForKey:@"UIKeyboardFrameBeginUserInfoKey"] CGRectValue];
//            CGRect end = [[[notification userInfo] objectForKey:@"UIKeyboardFrameEndUserInfoKey"] CGRectValue];
//            if(begin.size.height>0 && (begin.origin.y-end.origin.y>0)){
//                NSLog(@"contHeight is %ld", (long)contHeight);
//                NSLog(@"self.contentHeight is %ld", (long)self.contentHeight);
//                NSLog(@"duration is %f", duration);
//                
//                self.isKeyboardAnimating = YES;
//                duration = duration ? duration : 0.20;
//                
//                [UIView animateWithDuration:duration animations:^{
//                    self.frame = rect;
//                    self.contentHeight = contHeight;
//                } completion:^(BOOL finished) {
//                    _isKeyboardAnimating = NO;
//                }];
//            }