使用模拟器时，在调试时不小心按下了慢动画。 运行模拟器->调试->取消选中慢速动画。

简单的命令+ T将解决这个问题。

Command + T切换模拟器的慢速动画，可以在模拟器菜单下找到:Debug ->慢速动画。

React-Native用户的另一个潜在修复:

Chrome取消Javascript在任何标签中运行的优先级，而不是在前台。因此，如果启用了远程调试，请确保将调试器放在自己的窗口中。

转到模拟器的Debug菜单并选择“Toggle Slow Animations”。

更新:在Xcode 10中，它只是“慢动画”:

如果Cmd-T(慢动画)选项不适合您，并且调试->慢动画是关闭的，但您仍然有慢动画，请尝试模拟器->重置内容和设置(或可能是硬件->擦除所有内容和设置)。这里的其他答案都没用的时候，这个答案对我有用。有人知道为什么吗?

此外，附加调试器(完全)可能会使动画非常缓慢。

I don't have the rep yet to leave a comment, but I upvoted some answers here and wanted to say more. I had a problem with slow animations in the iOS Simulator, especially on rotation, and I found this post via Google. Indeed, somehow "Toggle Slow Animations" must have been on, because three shifts fixed it. At first, I didn't think this was a problem because there's no checkmark next to "Toggle Slow Animations." It turns out there's never a checkmark, or any indication from the menu whether it's on or off. So just try toggling it and see if the rotation/navigation is faster/slower.

所以，谢谢大家!