运行环境

Unity 5.3.5f1 （IL2CPP）编译IOS版本

XCode Version 7.2.1 (7C1002)

Mac OS X 10.11.3 (15D21) (Mac mini)

iPhone 5,6 ,iPad

错误信息

Could not produce class with ID

Could not produce class with ID XXX.
This could be caused by a class being stripped from the build even though it is needed. Try disabling ‘Strip Engine Code‘ in Player Settings.:<LoadWWWIEnumerator>c__Iterator99:MoveNext()

具体表现：可能是APP闪退，提示上示错误信息

解决办法

1. 在上面的错误提示中，有提示 disabling “Strip Engine Code”

所以我们要做的就是在Player Setting – Other Setting，去掉勾选 Strip Engine

如果要Strip Engine

如果要Strip Engine，那就需要把不想被strip的添加进来。

1. 新建link.xml放在Assets目录下，里面添加不想被strip的dll的名字

ID查询： https://docs.unity3d.com/Manual/ClassIDReference.html

下面是导入高通Vuforia之后，SDK中默认的link.xml的内容

<linker>    <!-- The following assemblies contain namespaces that should be fully preserved         even when assembly stripping is used. Not excluding the assemblies below from         stripping can result in crashes or various exceptions. -->    <assembly fullname="Vuforia.UnityExtensions">        <namespace fullname="Vuforia" preserve="all"/>    </assembly>    <assembly fullname="System">        <namespace fullname="System.Runtime.InteropServices" preserve="all"/>        <namespace fullname="System.Collections.Generic;" preserve="all"/>        <namespace fullname="System.Linq;" preserve="all"/>        <namespace fullname="System.Text.RegularExpressions;" preserve="all"/>        <namespace fullname="System.IO;" preserve="all"/>        <namespace fullname="System;" preserve="all"/>    </assembly></linker>

如果提示的ID的是Editor的，比如 AnimatorController(ID 91)属于Editor包里的，不能用link.xm加回来，可以在Resource下建一个空的prefab,在上面挂一个AnimatorController，打包时留下这个prefab就可以确保这个类不被strip掉了。

参考：https://forum.unity3d.com/threads/could-not-produce-class-with-id-91-ios.267548/

Unity的默认值

以Unity5.3.5为例

ios平台，默认勾选了 Strip Engine Code，且Script Background为I2CPP

android平台，默认disabled Strip Engine Code，且Script Background为Mono2x

IOS错误Could not produce class with ID