在iOS模拟器中，在顶部的栏中，单击调试→切换慢速动画(或Xcode 10+的慢速动画)。可能是你不小心打开的。

您可以尝试关闭远程调试(Cmd-D ->停止远程JS调试)。这通常会加快速度。

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。

这不仅仅是关于慢动画。Xcode模拟器的全局性能非常低。这是苹果的漏洞。我已经通过反馈助手报告了。我已经用代码创建了演示，演示模拟器比任何旧的实际设备慢200倍。我发现JavaScript代码与日期对象执行在WKWebView是模拟器的痛苦。改变模拟器中的选项在我的情况下没有帮助。查看jsfiddle https://jsfiddle.net/kjms16cw/我希望苹果能尽快修复它!

var log = document.getElementById("log"); document.getElementById("button").onclick = function() { run(); }; function run() { var d1 = new Date(); for (var i = 0; i < 1000; i++) { var x = new Date(); x.setMilliseconds(0); x.setSeconds(0); x.setMinutes(0); } var d2 = new Date(); log.innerHTML = ((d2.getTime() - d1.getTime()) / 1000) + " seconds"; } <h3>Xcode Simulator Extremely Low Performance</h3> <p>This test runs fast (several tens milliseconds e.g. 30 ms) in any browser any device any platform including very old iOS device e.g. iPhone 5C and several years old iPad 2, BUT IN SIMULATOR IT TAKES 6000 ms (yes, 6 seconds!). Terrible!</p> <button id="button">run()</button> <div id="log"></div>

我认为你错误地按了command + T而不是command + R。

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!