iOS奇葩问题一览（持续更新）

一、初始化ViewController出错

版本

Apple Swift version 3.0.2 (swiftlang-800.0.63 clang-800.0.42.1)
Target: x86_64-apple-macosx10.9
Xcode Version 8.2.1 (8C1002)

在用如下代码初始化ViewController时

storyboard.instantiateViewController

报出如下错误信息

Unknown class JWSwiftMineEditViewController in Interface Builder file.
Could not cast value of type 'UIViewController' (0x1b0d2ff50) to 'JWBizCardNew.JWSwiftMineEditViewController' (0x100dd1ab8).
原因相当奇葩，如图：

Module为None

这是StoryBoard上出错的ViewController的属性，我们可以看到这里的Module为None，这应该是Xcode的bug。
在Module栏里用鼠标左击一下，再按回车。会变成这个样子：

Module有值

这样，问题就解决了。

二、发http请求出错

版本

Apple Swift version 3.0.2 (swiftlang-800.0.63 clang-800.0.42.1)
Target: x86_64-apple-macosx10.9
Xcode Version 8.2.1 (8C1002)

Allow Arbitrary Loads已经设为YES了，发http请求还是报如下错误：

App Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure.

试了半天，发现Allow Arbitrary Loads in Web Content与Allow Arbitrary Loads不能共存。把Allow Arbitrary Loads in Web Content删掉就好了。

三、运行时报错：This application is modifying the autolayout engine from a background thread after the engine was accessed from the main thread. This can lead to engine corruption and weird crashes.

把子线程中针对UI的更新，放到主线程中执行即可。