Scrollview动画不流畅（Objective-C）

Question

I am trying to scroll my scroll view up when the textFieldDidBeginEditing delegate method is called. It works, but there is one buggy issue. On the FIRST call of the method (when the user taps the textview for the FIRST time, the animation is not smooth, and instantaneous jumps to the topPoint. Every animation afterwards is smooth. Why is the first animation not smooth like the other ones? Am I missing something?

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    CGPoint topPoint;
    topPoint = CGPointMake(0, 200);
    [self.scrollView setContentOffset:topPoint animated:YES];
}

Answer 1

这只发生在插入调试器时。它甚至会引起音频故障，我失去了几个小时的工作，甚至无缘无故地提交雷达：