iOS app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.
**2016-11-1714:47:20.205913ProjectName[1512:778965]Thisapplicationismodifyingtheautolayoutenginefromabackgroundthreadaftertheenginewasaccessedfro