pod install没有生成workspace 的问题

新项目里面安装 CocoaPods时没有生成workspace 查找资料后发现报错: [Xcodeproj]Unknownobject version.

因为Xcode 版本和 CocoaPods 的版本不匹配,需要更新 CocoaPods. 

更新:  gem install cocoapods --pre

提示错误 : You don't have write permissions for the /usr/bin directory.

解决方法: sudo gem install cocoapods --pre -n/usr/local/bin