1. You must get a key in google developer center, and register it in below function in AppDelegate.m file.
}
2. If during start up google map have below error in debug window, need to add -ObjC to Build Settings -> Linking -> Other Linker Flags.
2015-10-24 22:56:31.761 EasyQ[2510:176045] CoreData: Failed to load optimized model at path ‘/Users/Yanliyuan/Library/Developer/CoreSimulator/Devices/DFA41111-C50F-4C9B-8D01-DAD0F38BC6B9/data/Containers/Bundle/Application/9A82A689-5B32-4828-B54A-55112EB8BE17/EasyQ.app/GoogleMaps.bundle/GMSCacheStorage.momd/Storage.omo‘
2015-10-24 22:56:31.788 EasyQ[2510:176045] CoreData: Failed to load optimized model at path ‘/Users/Yanliyuan/Library/Developer/CoreSimulator/Devices/DFA41111-C50F-4C9B-8D01-DAD0F38BC6B9/data/Containers/Bundle/Application/9A82A689-5B32-4828-B54A-55112EB8BE17/EasyQ.app/GoogleMaps.bundle/GMSCacheStorage.momd/Storage.omo‘
2015-10-24 22:56:31.805 EasyQ[2510:176045] CoreData: Failed to load optimized model at path ‘/Users/Yanliyuan/Library/Developer/CoreSimulator/Devices/DFA41111-C50F-4C9B-8D01-DAD0F38BC6B9/data/Containers/Bundle/Application/9A82A689-5B32-4828-B54A-55112EB8BE17/EasyQ.app/GoogleMaps.bundle/GMSCacheStorage.momd/Storage.omo‘
2015-10-24 22:56:31.816 EasyQ[2510:176045] CoreData: Failed to load optimized model at path ‘/Users/Yanliyuan/Library/Developer/CoreSimulator/Devices/DFA41111-C50F-4C9B-8D01-DAD0F38BC6B9/data/Containers/Bundle/Application/9A82A689-5B32-4828-B54A-55112EB8BE17/EasyQ.app/GoogleMaps.bundle/GMSCacheStorage.momd/Storage.omo‘
2015-10-24 22:56:31.842 EasyQ[2510:176045] -[GMSMapView animateToCameraPosition:]: unrecognized selector sent to instance 0x7fd3727282f0
2015-10-24 22:56:31.875 EasyQ[2510:176045] *** Terminating app due to uncaught exception ‘NSInvalidArgumentException‘, reason: ‘-[GMSMapView animateToCameraPosition:]: unrecognized selector sent to instance 0x7fd3727282f0‘
IOS App Integrate Google Map Problems and Method to solve them
原文：http://www.cnblogs.com/shengguang/p/4908044.html