1. sending 'MainViewConroller *const_strong' to parameter of incompatible type ' 错误

   解决方案：http://stackoverflow.com/questions/24248825/getting-a-warning-setting-up-delegate-for-a-custom-protocol

   2.Unsupported Configuration    Scene is unreachable due to lack of entry points and  does not have an identifier for runtime access via  -instantiateViewControllerWithIdentifier:.

解决方案：http://stackoverflow.com/questions/13531035/xcode-scene-is-unreachable-due-to-lack-of-entry-points-but-cant-find-it

I am receiving the following error message: linker command failed with exit code 1 (use -v to see invocation)

This is happening with Apple's 'Your third iOS app' demo program. There are no dynamic errors displayed. The error message detail goes on to say; ld: duplicate symbol _OBJC_IVAR_$_STESimpleTextDocument._documentText in /Users/chris/Library/...

解决方案：http://stackoverflow.com/questions/10097489/xcode-linking-failure-message-what-does-it-mean

terminating with uncaught exception of type NSException

解决方案：http://stackoverflow.com/questions/17769245/terminating-with-uncaught-exception-of-type-nsexception