这是 FB SDK的问题，到官网看下解决方案吧。此回答整理自“应用研发平台EMAS开发者交流群”。

应用切换到到后台就报错。

解决方案
在Podfile的末尾添加以下内容：

```post_install do|installer|

解决问题一

find_and_replace("Pods/FBRetainCycleDetector/FBRetainCycleDetector/Layout/Classes/FBClassStrongLayout.mm",
"layoutCache[currentClass] = ivars;", "layoutCache[(id)currentClass] = ivars;")

解决问题二

find_and_replace("Pods/FBRetainCycleDetector/fishhook/fishhook.c",
"indirect_symbol_bindings[i] = cur->rebindings[j].replacement;", "if (i < (sizeof(indirect_symbol_bindings) /
sizeof(indirect_symbol_bindings[0]))) { \n indirect_symbol_bindings[i]=cur->rebindings[j].replacement; \n }")
end
def find_and_replace(dir, findstr, replacestr)
Dir[dir].each do |name|
FileUtils.chmod("+w",name) #add
text = File.read(name)
replace = text.gsub(findstr,replacestr)
if text != replace
puts "Fix: " + name
File.open(name, "w") { |file| file.puts replace }
STDOUT.flush
end
end
Dir[dir + '*/'].each(&method(:find_and_replace))
end
```

系统显示类似如下。

再重新执行Pod install。