pod install SDK "iphoneos" can not be located

pod install 时，显示如下错误：

xcrun:_ error: SDK "iphoneos" cannot be located
xcrun: error: SDK "iphoneos" cannot be located
xcrun: error: unable to lookup item 'Path' in SDK 'iphoneos'

解决办法：

sudo xcode-select --switch /Applications/Xcode.app