大概率是xcode 路径问题
通过执行如下命令来解决：

1. $: xcrun --sdk iphoneos --show-sdk-path

   error:"unable to lookup item 'Path' in SDK 'iphoneos'"
   

2. $ xcode-select --print-path

   /Library/Developer/CommandLineTools
   

3. $ xcodebuild -showsdks

   error：tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
   

4. $ sudo xcode-select --switch

    /Applications/Xcode.app/Contents/Developer/
   

5. $ xcrun --sdk iphoneos --show-sdk-path （成功）